Publisher：MDPI AG  

<jats:p>With the aging society in Japan, the number of elderly people residing in elderly facilities is increasing. In previous study, we developed a transfer assistive device designed to aid the elderly in transferring from the bedroom to the bathroom. Additionally, the device assists the elderly with standing and sitting to facilitate independent toileting activities. We verified that, throughout the entire transfer movement, the lumbar burden on caregivers remained below 3400 N. In this study, based on quantitative evaluation indices of transfer movements, the relationship between the lumbar burden on caregivers and factors such as psychological anxiety or cognitive impairment in the elderly during the use of a transfer assistive device was elucidated through motion analysis. We developed a control algorithm for the human–machine collaborative transfer system with the aim of alleviating the strain on the caregiver’s lower back while ensuring the elderly can use the device with peace of mind. The practicality of the control algorithm was verified.</jats:p>

DOI： 10.3390/act13030096

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Publisher：MDPI AG  

<jats:p>A thorough safety assessment of an automated driving system (ADS) is necessary before its introduction into the market and practical application. Scenario-based assessments have received significant attention in research. However, identifying sufficient critical scenarios for ADSs is a major challenge, especially for complex urban environments with a variety of road geometries, traffic rules, and traffic participants. To identify the critical scenarios in this complex environment, it is essential to understand the environmental factors that lead to safety-critical events (e.g., accidents and near-miss incidents). Thus, this study proposes a method for identification of critical scenario components by analyzing near-miss incident data and extracting environmental factors that induce driver errors. In this study, we applied the proposed method to a scenario, in which an ego vehicle makes a right turn at a signalized intersection with an oncoming vehicle approaching the intersection in left-hand traffic, as a case study. The proposed method identified two components (dynamic occlusion caused by oncoming right-turn vehicles and change in traffic lights) that were both critical and challenging for ADSs. The case study results showed the usefulness of the identified components and the validity of the proposed method, which can extract critical scenario components explicitly.</jats:p>

DOI： 10.3390/app131910770

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Language：English   Publisher：Fuji Technology Press Ltd.  

During the autonomous navigation of personal mobility vehicles (PMVs) in pedestrian spaces, avoiding collisions with pedestrians walking nearby is necessary. The avoidance paths of PMVs are affected by the behaviors of the pedestrians, which may also affect passenger comfort. Herein, a local path-planning method that considers passenger comfort to realize comfortable pedestrian avoidance during the autonomous navigation of PMVs in pedestrian spaces is proposed. First, the avoidance path and pedestrian behavior parameters affecting passenger comfort are investigated by evaluating passenger comfort in scenarios with different avoidance paths and pedestrian behaviors. Next, the requirements of a pedestrian avoidance method that considers passenger comfort are set based on the parameters affecting passenger comfort. Finally, a novel path-planning method that satisfies the requirements is proposed. The method is shown to generate comfortable paths in pedestrian spaces via a numerical simulation and participant experiment.

DOI： 10.20965/jrm.2023.p0231

DOI： 10.20965/jrm.2023.p1562_references_DOI_L9BzZvUrZQE1QYCaUobpaWoQ2Vs

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I032772209

Language：English   Publishing type：Research paper (scientific journal)  

AIM: Healthy older drivers may be at high risk of fatal traffic accidents. Our recent study showed that volumetric alterations in gray matter in the brain regions within the dorsal attention network (DAN) were strongly related to the risk of unsafe driving in healthy older people. However, the relationship between white matter (WM) structural connectivity and driving ability in healthy older people is still unclear. METHODS: We used diffusion tensor imaging to examine the association between microstructural alterations in the DAN and the risk of unsafe driving among healthy older people. We enrolled 32 healthy older individuals aged over 65 years and screened unsafe drivers using an on-road driving test. We then determined the pattern of WM aberrations in unsafe drivers using tract-based spatial statistics. RESULTS: The analysis demonstrated that unsafe drivers had significantly higher axial diffusivity values in nine WM clusters compared with safe drivers. These results were primarily observed bilaterally in the dorsal superior longitudinal fasciculus, which is involved in the DAN. Furthermore, correlation analyses showed that higher axial diffusivity values in the superior longitudinal fasciculus were associated with lower Trail Making Test A scores within unsafe drivers. This result suggests that functionally, WM microstructural alterations in the DAN are associated with attention problems, which may contribute to the risk of unsafe driving among healthy older people. CONCLUSION: Our findings may elucidate the neurobiological mechanisms underlying the increased risk of unsafe driving in healthy older people, potentially facilitating the development of new interventions to prevent fatal accidents.

DOI： 10.1002/pcn5.45

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Language：English   Publisher：Society of Automotive Engineers of Japan, INC  

Indoor temperature affects the arousal level and thermal comfort of drivers. In this study, we aim to prevent the drowsy state and to improve the thermal comfort of drivers in driving for a long time using changes in ambient temperature in cabin. Targeting the scene of driving for 90 minutes, the hypothesis that repeated thermal stimulation to the driver can prevent the decrease of arousal level and thermal comfort of the driver was tested. We investigated the drowsiness level, thermal comfort based on subjective evaluation, and physiological parameters of the driver in the condition of repeated thermal stimulation for 90 min with driving in a simulator. As a result, the drowsiness level with a scale from 0 (alert) to 4 (extremely drowsy) was kept below 1 (slightly drowsy), and the comfort sensation with a scale from -3 (very uncomfortable) to 0 (comfortable) was maintained above -1 (slightly uncomfortable). These results suggest that repeated thermal stimulation is valid to prevent the decrease of arousal level and thermal comfort of the driver.

DOI： 10.20485/jsaeijae.13.2_83

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In Japan, the aging population is expected to increase the number of elderly people in the future. The purpose of this study was to develop a hip lift transfer assistive system to improve the QOL of elderly living and to prevent back pain for caregivers. We extracted the impediment factor and the necessary scene for the assistance, decided on the transfer process from the wheelchair in the toilet, and considered the reduction method of the burden based on the quantitative evaluation of the caregiver's lumbar burden and developed the device. Then we proposed the algorithm of the system by grasping the behavior and lumbar burden characteristics at the time of using the hip lift transfer assistive system by the developed device in which the proposed support algorithm of standing seating assistance operation is implemented in the actual use environment. Through the assistive movement evaluation experiment and the actual operation in the toilet, we have verified that the use of this device can reduce the caregivers' lumbar burden below the standard value (3400 N) and have proved the effectiveness of the proposed transfer assistive system.

DOI： 10.3390/s21227548

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Publisher：Elsevier BV  

Abstract An automated mobility scooter is expected to provide convenient and safe transportation for users in their living area. However, there is limited research on user comfort compared to that on user safety for the automated driving of mobility scooters. Because the user does not perform driving tasks in automated driving, the visual information from the peripheral environment and visual behavior is expected to closely affect the psychological comfort of the user. This study clarifies the effects of factors related to the automated driving of mobility scooters and the peripheral environment on the visual behavior and psychological comfort of the user. Effects of driving velocity and pedestrian density on the visual behavior and psychophysiological responses of users were investigated via a driving simulator. The results showed that automated driving in an environment with a high pedestrian density can result in a decrease in fixation duration, deactivation of visual processing, sympathetic activation, and feeling of negative emotion. This implies that the assessment of visual behaviors of users is important for the design of automated mobility scooters to improve user comfort.

DOI： 10.1016/j.trf.2021.07.011

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Detection of traversable areas is essential to navigation of autonomous personal mobility systems in unknown pedestrian environments. However, traffic rules may recommend or require driving in specified areas, such as sidewalks, in environments where roadways and sidewalks coexist. Therefore, it is necessary for such autonomous mobility systems to estimate the areas that are mechanically traversable and recommended by traffic rules and to navigate based on this estimation. In this paper, we propose a method for weakly-supervised recommended traversable area segmentation in environments with no edges using automatically labeled images based on paths selected by humans. This approach is based on the idea that a human-selected driving path more accurately reflects both mechanical traversability and human understanding of traffic rules and visual information. In addition, we propose a data augmentation method and a loss weighting method for detecting the appropriate recommended traversable area from a single human-selected path. Evaluation of the results showed that the proposed learning methods are effective for recommended traversable area detection and found that weakly-supervised semantic segmentation using human-selected path information is useful for recommended area detection in environments with no edges.

DOI： 10.3390/s21020437

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AIM: In Japan, fatal traffic accidents due to older drivers are on the rise. Considering that approximately half the older drivers who have caused fatal accidents are cognitively normal healthy people, it has been required to detect older drivers who are cognitively normal but at high risk of having fatal traffic accidents. However, a standardized method for assessing the driving ability of older drivers has not yet been established. We thus aimed to identify a new sensing method for the evaluation of the on-road driving ability of healthy older people on the basis of vehicle behaviors. METHODS: We enrolled 33 healthy older individuals aged over 65 years and utilized a machine-learning approach to dissociate unsafe drivers from safe drivers based on cognitive assessments and a functional visual acuity test. RESULTS: The linear support vector machine classifier successfully dissociated unsafe drivers from safe drivers with accuracy of 84.8% (sensitivity of 66.7% and specificity of 95.2%). Five clinical parameters, namely age, the first trial of the Rey Auditory Verbal Learning Test immediate recall, the delayed recall of the Rey-Osterrieth Complex Figure Test, the result of the free-drawn Clock Drawing Test, and maximal visual acuity, were consistently selected as essential features for the best classification model. CONCLUSION: Our findings improve our understanding of clinical risk factors leading to unsafe driving and may provide insight into a new intervention that prevents fatal traffic accidents caused by healthy older people.

DOI： 10.1111/pcn.13084

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Language：English   Publishing type：Research paper (scientific journal)  

Individuals with severe physical impairments have difficulties operating electric wheelchairs (EWs), especially in situations where fine steering abilities are required. Automatic driving partly solves the problem, although excessive reliance on automatic driving is not conducive to maintaining their residual physical functions and may cause more serious diseases in the future. The objective of this study was to develop a shared control system that can be adapted to different environments by completely utilizing the operating ability of the user while maintaining the motivation of the user to drive. The operating characteristics of individuals with severe physical impairments were first analyzed to understand their difficulties when operating EWs. Subsequently, a novel reinforcement learning-based shared control method was proposed to adjust the control weight between the user and the machine to meet the requirements of fully exploiting the operating abilities of the users while assisting them when necessary. Experimental results showed that the proposed shared control system gradually adjusted the control weights between the user and the machine, providing safe operation of the EW while ensuring full use of the control signals from the user. It was also found that the shared control results were deeply affected by the types of users.

DOI： 10.3390/ijerph17155502

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Language：English   Publisher：Fuji Technology Press Ltd.  

In this study, we proposed an autonomous motion planning method for improving passenger comfort while ensuring safety, particularly with respect to mobility scooters used by elderly people. We proposed a trajectory planner for restricting vehicle behaviors with large accelerations and jerks by selecting a safe trajectory from a set of preset trajectories. Then, based on this trajectory planner, we developed an autonomous motion planning method with four different driving modes, and evaluated the effectiveness of the method through a numerical simulation. The simulation results demonstrated that the proposed method increased comfort without compromising on safety.

DOI： 10.20965/jrm.2020.p0580

DOI： 10.20965/jrm.2023.p0231_references_DOI_1cWmMhNmcDQNTEVHG9APlLkMfN4

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I030459521

Publisher：Springer Science and Business Media LLC  

<jats:title>Abstract</jats:title><jats:p>The wheelchair is the major means of transport for elderly and physically disabled people in their daily lives. However it cannot overcome architectural barriers such as curbs and stairs. In this study, we developed an inverted-pendulum-type robotic wheelchair for climbing stairs. This wheelchair has a seat slider and two rotary links between the front and rear wheels on each side. When climbing stairs, the wheelchair rotates the rotary links while maintaining an inverted state of a mobile body by controlling the position of the center of gravity using a seat slider. In previous research, we confirmed that the wheelchair can climb by applying the control method consisting of a center-of-gravity control phase and rotary link control phase. However, it took approximately 15 s to rotate the rotary links during climbing because faster climbing causes the movement of wheels and the wheelchair to fall. This paper focuses on a control method to restrain the movement of the wheels when the stair climbing speed is increased. We realized that the movement was caused by forces acting on the pitch angle, such as the inertial force and the reaction of the driving force. We proposed the method considering the dynamic equilibrium of the pitch angle and confirmed the effect of the restraining wheels’ movement when the proposed method was applied.</jats:p>

DOI： 10.1186/s40648-020-00171-4

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Publisher：MDPI AG  

<jats:p>Drowsy driving is one of the main causes of traffic accidents. To reduce such accidents, early detection of drowsy driving is needed. In previous studies, it was shown that driver drowsiness affected driving performance, behavioral indices, and physiological indices. The purpose of this study is to investigate the feasibility of classification of the alert states of drivers, particularly the slightly drowsy state, based on hybrid sensing of vehicle-based, behavioral, and physiological indicators with consideration for the implementation of these identifications into a detection system. First, we measured the drowsiness level, driving performance, physiological signals (from electroencephalogram and electrocardiogram results), and behavioral indices of a driver using a driving simulator and driver monitoring system. Next, driver alert and drowsy states were identified by machine learning algorithms, and a dataset was constructed from the extracted indices over a period of 10 s. Finally, ensemble algorithms were used for classification. The results showed that the ensemble algorithm can obtain 82.4% classification accuracy using hybrid methods to identify the alert and slightly drowsy states, and 95.4% accuracy classifying the alert and moderately drowsy states. Additionally, the results show that the random forest algorithm can obtain 78.7% accuracy when classifying the alert vs. slightly drowsy states if physiological indicators are excluded and can obtain 89.8% accuracy when classifying the alert vs. moderately drowsy states. These results represent the feasibility of highly accurate early detection of driver drowsiness and the feasibility of implementing a driver drowsiness detection system based on hybrid sensing using non-contact sensors.</jats:p>

DOI： 10.3390/app10082890

DOI： 10.20485/jsaeijae.13.2_83_references_DOI_KWIosAsSGMZqkJSIOJlF4NvSlDh

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Towards reduction of right-turn accidents at intersections involving pedestrians, we investigated the influence of traffic environments on rightturn driving behavior. Aiming to apply the driving behavior indices, which we proposed in our previous study, to right turns at intersections on public roads, we investigated the relationship between the indices and traffic environment using Naturalistic Driving Study (NDS) data. Analysis results of NDS data revealed that presence of stop signs and traffic signals, width of both intersections’ entrance and exit roads and crossing angle of the intersection are traffic environment elements that need to be considered when assessing collision risk with the driving behavior indices.

DOI： 10.11351/jsaeronbun.51.333

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In developed countries, the number of traffic accidents caused by older drivers is increasing. Approximately half of the older drivers who cause fatal accidents are cognitively normal. Thus, it is important to identify older drivers who are cognitively normal but at high risk of causing fatal traffic accidents. However, no standardized method for assessing the driving ability of older drivers has been established. We aimed to establish an objective assessment of driving ability and to clarify the neural basis of unsafe driving in healthy older people. We enrolled 32 healthy older individuals aged over 65 years and classified unsafe drivers using an on-road driving test. We then utilized a machine learning approach to distinguish unsafe drivers from safe drivers based on clinical features and gray matter volume data. Twenty-one participants were classified as safe drivers and 11 participants as unsafe drivers. A linear support vector machine classifier successfully distinguished unsafe drivers from safe drivers with 87.5% accuracy (sensitivity of 63.6% and specificity of 100%). Five parameters (age and gray matter volume in four cortical regions, including the left superior part of the precentral sulcus, the left sulcus intermedius primus [of Jensen], the right orbital part of the inferior frontal gyrus, and the right superior frontal sulcus), were consistently selected as features for the final classification model. Our findings indicate that the cortical regions implicated in voluntary orienting of attention, decision making, and working memory may constitute the essential neural basis of driving behavior.

DOI： 10.3389/fnagi.2020.592979

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In recent years, the number of traffic accidents caused by elderly drivers have been increasing. In order to develop driver assistance system, it is necessary to analysis driver’s driving behavior to extract unsafe driving behavior. In this paper, we propose a method that estimate face pose and leaning forward posture by using on-board camera image. We discuss the safety of driving behavior of expert drivers using leaning forward posture.

DOI： 10.11351/jsaeronbun.51.161

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Publisher：SAGE Publications  

DOI： 10.3233/tad-190225

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Publisher：MDPI AG  

<jats:p>Thermal factors not only affect the thermal comfort sensation of occupants, but also affect their arousal level, productivity, and health. Therefore, it is necessary to control thermal factors appropriately. In this study, we aim to design a thermal environment that improves both the arousal level and thermal comfort of the occupants. To this end, we investigated the relationships between the physiological indices, subjective evaluation values, and task performance under several conditions of changes in the indoor ambient temperature. In particular, we asked subjects to perform a mathematical task and subjective evaluation related to their thermal comfort sensation and drowsiness levels. Simultaneously, we measured their physiological parameters, such as skin temperature, respiration rate, electroencephalography, and electrocardiography, continuously. We investigated the relationship between the comfort sensation and drowsiness level of occupants, and the physiological indices. From the results, it was confirmed that changes in the indoor ambient temperature can improve both the thermal comfort and the arousal levels of occupants. Moreover, we proposed the evaluation indices of the thermal comfort and the drowsiness level of occupants using physiological indices.</jats:p>

DOI： 10.3390/app9050899

DOI： 10.20485/jsaeijae.13.2_83_references_DOI_3V5dHsRqTURIOroA72lVxuaZOJb

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Changes in indoor temperature affect arousal level and thermal comfort of driver. In this research, we aim to prevent the drowsy driving of drivers and to improve the thermal comfort. We evaluate the effect of the changing pattern of indoor temperature on the arousal level and thermal comfort of driver based on subjective evaluations, physiological parameters and driving performance utilizing driving simulator. As a result, the arousal level increased and maintained at an alert state, corresponding to the changes in the thermal comfort sensation due to decreasing of indoor temperature, and then it was maintained at a high state, although the indoor temperature rose and the drivers felt comfortable. These results showed that it is possible to improve both the arousal level and thermal comfort of the drivers by control the changing patterns in indoor temperature.

DOI： 10.11351/jsaeronbun.50.1446

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I030058821

Language：English   Publisher：Society of Automotive Engineers of Japan, INC  

The objective of this study was to develop indices for detecting a driver’s state that consider the driver’s judgment process in various circumstances using a naturalistic driving behavior database. The deceleration timing when a driver approaches a non-signalized intersection was considered, and a deceleration strategy for the approach to an intersection was formulated based on a naturalistic driving behavior database compiled from the real world. A deviated state detection method that incorporates the formulated strategy is proposed, and the validity of the method was examined.

DOI： 10.20485/jsaeijae.10.1_106

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Towards reduction of right-turn accidents at intersections involving pedestrians, we investigated whether change in driving behavior is effective to reduce collision risk against crossing pedestrians. Using a driving simulator, we conducted an experiment changing the driving behavior of participants intentionally by applying operation intervention methods while drivers made right turns at intersections. Experiment results revealed that collision risk against crossing pedestrians can be reduced by the change of drivers’ behavior in accordance with driving behavior indices which can evaluate pedestrian-collision-risk of right-turn maneuvers at intersections.

DOI： 10.11351/jsaeronbun.50.480

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I029595253

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Towards prevention of traffic accidents involving pedestrians, the objective of this study is to construct a pedestrian collision risk assessment method of right-turns at intersections based on driving behavior indices related to drivers’ risk anticipation for driver-assistance systems. In this paper, first, environmental elements that affect driving behavior was selected based on naturalistic driving data. Next, the influence of the environmental elements was examined by a risk-scene reproducing experiment. Results showed that road width affects collision risk assessment and collision risk of different road width conditions could possibly be evaluated by additional consideration of vehicle position and direction.

DOI： 10.11351/jsaeronbun.49.372

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I028916886

Language：English   Publisher：Society of Automotive Engineers of Japan, INC  

Driving comfort and driving safety are essential factors for drivers. As the environment of vehicle affects the comfort sensation and the arousal level of the drivers, it is necessary to contemplate the way to design of environmental factors inside vehicle. In this study, we focus on the thermal factors inside vehicle, and we aim to design a thermal environment which can improve both the thermal comfort and the arousal level of drivers. In our previous research, we showed that the changes in indoor temperature have possibility to improve both the comfort sensation and the arousal level of driver by analyzing the subjective parameters. To clarify the design requirements, it is needed to evaluate the thermal comfort and the arousal level of drivers continuously, quantitatively and separately. So, we focused on the physiological parameters which can be measured continuously, we investigated the relationship between the thermal comfort sensation, the arousal level of drivers based on facial expression and the physiological parameters, such as Electroencephalogram (EEG) and Electrocardiogram (ECG) when the indoor temperature changed. As a result, we showed that it is possible to evaluate the thermal comfort sensation and the arousal level of drivers quantitatively, continuously and separately by using those physiological parameters.

DOI： 10.20485/jsaeijae.9.2_86

DOI： 10.20485/jsaeijae.12.2_32_references_DOI_GxrYG67ahBTmbKSOxMbyFUqN8uC

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan, INC  

Our research aims to investigate the relation between the driving behavior in the actual environment and the cognitive ability for elderly drivers. To examine the planning process during driving, we analyzed the driving behavior of passing through an intersection with a stop sign and lane changing during driving. As a result of the analysis, about 70% of elderly drivers didn’t drive safely just like driving instructors. Moreover, it was found that elderly drivers of Mild Cognitive Impairment (MCI) group had lower divided attention and alternating attention than that of non-MCI group. The drivers of MCI group were more difficult to decide a task during driving than that of non-MCI group.

DOI： 10.20485/jsaeijae.9.3_138

DOI： 10.3389/fnagi.2020.592979_references_DOI_OQHJhYSaM5ekhE0H49jBbvohhka

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16H03130/

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

In this study, we aim to design a thermal environment that improves both the arousal level and the thermal comfort of the drivers. We conducted experiments using driving simulator, in order to investigate the effects of changes in indoor temperature on the arousal level and the thermal comfort of the drivers, and the driving performance due to the changes in the arousal level. As a result, the arousal level increased and maintained at an alert state, corresponding to the fall in indoor temperature, and then it was maintained at a high state, although the indoor temperature rose and the drivers felt comfortable after the temperature fell and the arousal level rose. These results showed that it is possible to improve both the arousal level and thermal comfort of the drivers by periodic changes in indoor temperature.

DOI： 10.11351/jsaeronbun.49.365

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I028916850

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

The significant problem for active safety system and ADAS (Advanced Driving Assistance System) is how to recognize driver behavior such as where driver look in a scene or what driver aware of their environment. In order to recognize the driver behavior, it is necessary to estimate gaze direction and gaze region in forward environments. In this paper, we propose a method that estimate gaze direction and extract driver’s gaze region in forward image using estimated head pose from in-vehicle cameras.

DOI： 10.11351/jsaeronbun.48.1113

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I028581452

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Reducing workload during ingress/egress is important to improve the usability of automotive for elderly users. In this study, we analyzed the relationships between motion features and physical features of elderly people. The muscular loads during their ingress were measured and the sitting motion, putting down pelvis to seat, caused dominant workload in ingress. The vertical axial velocity of pelvis during sitting motion was extracted as the load factor. Based on evaluation results, we proposed a new interior design and confirmed that it decreased workload and improved comfort of ingress to a certain extent.

DOI： 10.11351/jsaeronbun.48.477

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Language：English   Publishing type：Research paper (scientific journal)  

Persons with severe Duchenne Muscular Dystrophy (DMD) usually have difficult in operating electric wheelchairs (EW) using standard input device due to the lack of muscular power and the deformation of their hands. This paper proposed a novel one dimensional two degree of freedom (1D2F) input device based on the quantitative evaluation of hand function which consists of fingertip force and active range of motion. The validity and the operating features of this device are demonstrated by experiments.

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Towards prevention of traffic accidents involving pedestrians, the objective of this study is to construct a pedestrian collision risk assessment method of right turns at intersections for driver assistance systems based on driving behavior indices related to drivers’ risk anticipation. In this paper, we focused on 2 typical right-turn pedestrian collision scenes, one with no other traffic participants and the other with oncoming vehicles, and extracted risk assessment indices based on near-miss incident analysis. The extracted indices were validated through a risk scene reproducing experiment using the JARI-ARV and driving behavior features affecting collision risk were examined based on the results.

DOI： 10.11351/jsaeronbun.48.921

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

This study proposes an avoidance method of crossing collision of micro electric vehicles (MEV) based on the prediction of collision forms. Avoidable space is considered in the method and the avoidable space is influenced by the intersection shape and the behavior of crossing vehicles when they avoid the other vehicles by accelerating, decelerating and steering. In this paper, the authors made such articles clear for this method as the MEV’s braking level, the decelerating crossing vehicle into an intersection and the effect by a cross angle of the intersection.

DOI： 10.11351/jsaeronbun.48.867

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Language：English   Publishing type：Research paper (scientific journal)  

Electric powered wheelchairs (EPWs) are essential devices for people with disabilities as aids for mobility and quality of life improvement. However, the design of currently available common EPWs is still limited and makes it challenging for the users to drive in both indoor and outdoor environments such as uneven surfaces, steep hills, or cross slopes, making EPWs susceptible to loss of stability and at risk for falls. An alternative wheel-legged robotic wheelchair, "MEBot", was designed to improve the safety and mobility of EPW users in both indoor and outdoor environments. MEBot is able to elevate its six wheels using pneumatic actuators, as well to detect changes in the seat angle using a gyroscope and accelerometer. This capability enables MEBot to provide sensing for a dynamic self-leveling seat application that can maintain the center of mass within the boundaries of the wheelchair, thereby, improving EPW safety. To verify the effectiveness of the application, MEBot was tested on a motion platform with six degrees of freedom to simulate different slopes that could be experienced by the EPW in outdoor environments. The results demonstrate the robustness of the application to maintain the wheelchair seat in a horizontal reference against changes in the ground angle.

DOI： 10.1016/j.medengphy.2015.12.007

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In a bathing environment, it is needed to evaluate an emotional effect quantitatively and continuously at stage of the product design for improving stress-relaxation effect. This study aimed to propose an index which can evaluate the comfort quantitatively and continuously on bathing. To search the physiological indices correlated to the comfortable feeling, we measured subjective evaluation of comfortable feeling in one-minute increments, with continuous measurement of physiological parameter before bathing, on bathing, after bathing. We analyzed the relationship between time-series data of the subjective evaluation and the physiological parameter. As a result, we proposed the evaluation index of comfortable feeling by using HF content obtained from spectral analysis of heart rate variability, and confirmed that the evaluation index can evaluate comfortable feeling quantitatively and continuously including the effect of personal preferences related to bathing.

DOI： 10.1299/transjsme.16-00092

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Critical situations with pedestrians while driving on non-intersection road are happen not only hidden pedestrians behind obstructions but also visible pedestrians on a sidewalk. It was one of a feature of critical situation at non-intersection road in previous studies. In this study, we hypothesize that one of the cause is driver's prediction for a pedestrians who will / will not be crossing the road. Therefore, we took an experiment in a test field to confirm the effect of the prediction to pedestrians and analysed vehicle speed and driver's eye movement.

DOI： 10.11351/jsaeronbun.47.543

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Observing the driver's behavior by reproducing traffic accidents and conflict situations are effective in investigating the causes of accidents. Therefore, JARI-ARV was developed to reproduce realistic traffic accident and conflict scenarios without putting the driver at risk of an actual collision. JARI-ARV was equipped with three Liquid - Crystal - Displays (LCD) and three video cameras in front of the driver. However, there are some differences between JARI-ARV and standard vehicle. One of the most grately different portion is visual information. Drivers use three dimensional visual information in a standard vehicle, but two dimensional information is used in driving JARI-ARV. It is need to confirm some differences between JARI-ARV and standard vehicle. In this paper, we confirmed drivers' maneuver (gas pedal off, brake pedal on, steering, gas pedal on) and vehicle behavior (deceleration, lateral acceleration, yaw rate, acceleration) in a right turn at an intersection, by comparing JARI-ARV with a standard vehicle. As a result, drivers' maneuver and vehicle behavior in right turns were almost the same between JARI-ARV and standard vehicle.

DOI： 10.11351/jsaeronbun.46.665

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Publisher：SAGE Publications  

Persons with severe Duchenne muscular dystrophy (DMD) cannot operate electric wheelchairs through standard joysticks because they lack muscular power and are affected by deformation of the hands. To address this difficulty, first the authors determined the requirements of input devices based on a survey of the daily life of persons with DMD and the authors developed new joysticks for an electric wheelchair considering the characteristics of the hand functions of persons with DMD. These devices were based on a quantitative evaluation of the hand functions of persons with severe DMD, which consists of fingertip force and range of motion of the fingers. Two new joysticks were developed, considering hand function, posture, and hand shape of two persons with severe DMD. Thus, the devices can be operated using slight force and movement of the fingers. Furthermore, the authors examined the shape of the hands of persons with severe DMD to determine the shape of the devices.

DOI： 10.3233/tad-140412

DOI： 10.15748/jasse.7.300_references_DOI_BPSdkMu5ZeFuyRH33CY4yu2yJeJ

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Publisher：Springer Science and Business Media LLC  

The objective of this study is to propose the indices which detect the deviated state of drivers while driving by considering drivers’ judgment process and using road environment and naturalistic driving behavior database. To realize this objective, drivers’ speed choice behavior around curve situations was focused and the speed choice process was formulated. Moreover, a deviated state detection method considering the formulated speed choice process around curve situations was proposed and the validity of the method was examined.

DOI： 10.1007/s12239-014-0078-7

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

The relationship between near-miss incidents, as a substitute characteristic for traffic accidents, and driver behavior indexes was made clear in order to develop a method of quantitatively assessing safe driver behavior based on accident risk. Several driver behavior indexes were first formulated from actual accident circumstances, focusing on crossing-path accidents at stop sign intersections, which frequently occur in Japan. Using a naturalistic driving database, driver behavior indexes correlated with near-miss incidents were then identified. The indexes were then validated by conducting driving tests in a proving ground to clarify the respective mechanism leading from such driver behavior to near-miss incidents.

DOI： 10.11351/jsaeronbun.45.717

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I025744478

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: This paper describes the development of a mobile base for the Personal Mobility and Manipulation Appliance Generation II (PerMMA Gen II robotic wheelchair), an obstacle-climbing wheelchair able to move in structured and unstructured environments, and to climb over curbs as high as 8 inches. The mechanical, electrical, and software systems of the mobile base are presented in detail, and similar devices such as the iBOT mobility system, TopChair, and 6X6 Explorer are described. FINDINGS: The mobile base of PerMMA Gen II has two operating modes: "advanced driving mode" on flat and uneven terrain, and "automatic climbing mode" during stair climbing. The different operating modes are triggered either by local and dynamic conditions or by external commands from users. A step-climbing sequence, up to 0.2 m, is under development and to be evaluated via simulation. The mathematical model of the mobile base is introduced. A feedback and a feed-forward controller have been developed to maintain the posture of the passenger when driving over uneven surfaces or slopes. The effectiveness of the controller has been evaluated by simulation using the open dynamics engine tool. CONCLUSION: Future work for PerMMA Gen II mobile base is implementation of the simulation and control on a real system and evaluation of the system via further experimental tests.

DOI： 10.1179/2045772313Y.0000000094

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Traffic accidents involving elderly drivers are major concerns in Japan. Age-related decline in cognitive function is said to be one of the causes of these accidents, so it is important to propose driving support system considering cognitive ability to reduce these accidents. It is necessary to clarify the relation between cognitive ability and driving behavior of elderly drivers. We measured cognitive characteristics of elderly drivers and proposed a method to classify elderly drivers based on cognitive characteristics and examined the relation between cognitive ability and unsafe driving behavior.

DOI： 10.1299/kikaic.78.3362

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23300207/

Language：English   Publishing type：Research paper (scientific journal)  

The Personal Mobility and Manipulation Appliance (PerMMA) is a recently developed personal assistance robot developed to provide people with disabilities and older adults enhanced assistance in both mobility and manipulation, which are two fundamental components for independently activities of daily life performing, community participation, and quality of life. Technologies to assist with mobility and manipulation are among the most important tools for clinicians, end users and caregivers; however, there are currently few systems that provide practical and coordinated assistance with mobility and manipulation tasks. The PerMMA was not only developed and evaluated to provide users and caregivers enhanced mobility and manipulation options, but also as a clinical tool as well as research platform. The development and evaluation of PerMMA are presented in the paper.

DOI： 10.1109/EMBC.2012.6346676

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Language：Japanese   Publisher：京都 : ヒューマンインタフェース学会  

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Language：Japanese   Publisher：Human Interface Society  

The purpose of this research is to assist older persons confused in using information devices by giving appropriate guidance. First, we describe a model of cognition-action interaction in using information devices. Second, we report an experiment that investigated the relationship between behavior of users and their confused states. We found that the task completion times and vertical and horizontal scanpath lengths were found to be related to confused state. Third, we suggest a recognition method of the confused state. At last we report an experiment that investigated the effect of the recognition method and the classified confused state.

DOI： 10.11184/his.13.2_147

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Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The automobile has an important impact on the daily lives of elderly people and their ability to participate in society. However, the deterioration of physical skills caused by aging is also a cause of vehicular accidents. In this paper, we conduct research into the cognitive function on driving ability, and propose a method to evaluate the driving ability of elderly drivers. The proposed system that the system is a computer simulator rather than an actual on-road driving experiment evaluates the ability to follow a road, the ability to avoid obstacles, and the ability to escape from unexpected dangers. To identify the operating characteristics and define an assessment index, 102 people over the age of 65 were surveyed on their driving attitudes. The investigation showed that the tasks and assessment index, and based on this system, another 92 elderly people participated in evaluation tests. The results showed there was a significant difference between elderly and younger drivers in terms of road-following and obstacle-avoidance ability. In addition, an assessment index with a five-level rating system, based on the characteristics of elderly drivers, was proposed.

DOI： 10.1299/kikaic.77.4591

DOI： 10.1002/ecj.12049_references_DOI_3VyYylft8uucjwVdtNJZW5B4ZwT

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23300207/

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Although understanding the risk factors with suitable evaluation indices is useful in order to improve the safety of vehicle driving, there is no evaluation index for low-speed vehicles on pedestrian spaces. Because the characteristics of pedestrian spaces as driving environment is different from that of roadway for automobiles, we do not directly use the existing evaluation indices proposed in research field of automobiles. Therefore, we constructed an evaluation index for low-speed vehicles driving on pedestrian spaces. At first, we compared the characteristics of the driving situations of existing indices to that of our target situation, and proposed the evaluation index “Ellipse-Mapped Relative Risk”. Next, we confirmed the characteristics of proposed index by simulation and experiment. From the results of simulation, EMRR’s ability to evaluate the apparent risk in various driving situations was confirmed. On the other hand, from the results of experiment, consistency for the risk perception of the drivers was confirmed. At last, with the proposed evaluation index, a risk effect of pedestrians was partly confirmed as the first step of understanding the risk mechanisms.

DOI： 10.1299/jmtl.4.24

DOI： 10.1299/mej.14-00568_references_DOI_KzADBJ8amfzP5QUijXlQKdMv1sw

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10J08623/

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

We propose an entirely new model of the electric wheelchair that consists of the castors and the main body. The equations of motion about the castors and the main body are derived by the physical law. In particular, the dynamics of the castor is considered in this study. In order to confirm the validity of the constructed electric wheelchair model, the comparison between the experimental result and the simulation result about the castor behavior is performed. Then, we examine the parameter of the electric wheelchair to suppress the disturbance (for example, the behavior of the castor and the road gradient) as an application of the proposed model.

DOI： 10.1299/kikaic.76.682

DOI： 10.1299/transjsme.20-00009_references_DOI_TO0V3nKgGoocOJ85IzqmD3rxK7P

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I10637504

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In Japan, snow removal requires a detailed understanding of the particular type of climates, the road configuration, and road surface condition on sidewalk. The sidewalk is always changed by unexpected several operation condition, such as road condition and movement of several maneuver obstacles. Snow removing operation on sidewalk depends on operator's experience and physical ability. The goal of this research is mainly to clarify a strategy for designing the operation assistance system to improve safety and task performance by analyzing information processing ability of each operator during operation. This paper proposes a quantitative evaluation method of operator's information processing ability during operation actions and verifies the effectiveness of the method by using simulator.

DOI： 10.1299/kikaic.76.407

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I10599817

Language：English   Publisher：The Japan Society of Mechanical Engineers  

This paper describes the construction of a driver model of a powered wheelchair operation for the understanding of the characteristics of the driver. The main targets of existing researches about driver models are the operation of the automobiles and motorcycles, not a low-speed vehicle such as powered wheelchairs. Therefore, we started by verifying the possibility of modeling the turning operation at a corner of a corridor. At first, we conducted an experiment on a daily powered wheelchair user by using his vehicle. High reproducibility of driving and the driving characteristics for the construction of a driver model were both confirmed from the result of the experiment. Next, experiments with driving simulators were conducted for the collection of quantitative driving data. The parameters of the proposed driver model were identified from experimental results. From the simulations with the proposed driver model and identified parameters, the characteristics of the proposed driver model were analyzed.

DOI： 10.1299/jmtl.3.380

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Language：English   Publisher：The Japan Society of Mechanical Engineers  

The purpose of a powered wheelchair driving simulator is to decrease the time and effort in the process of clinic, research and development. In this paper, the design concepts of our driving simulator for research and development use are explained. To design the simulator's software and hardware, two following experiments were conducted. 1: The driver's horizontal field of view was measured. While making a right turn at a corner of a corridor, the movement of the driver's gazing point was measured. From this result, the maximum and minimum values of gazing point movement were analyzed to design the simulator's angle of view. 2: Motion cues such as acceleration and vibration were measured. The characteristics of these motion cues were analyzed to design the motion system. From the experiment results, a driving simulator of a powered wheelchair was developed. To evaluate the driving simulator, the experiment for comparing with a real powered wheelchair driving was conducted. Evaluations improved by the components which were specially designed for the driving simulator.

DOI： 10.1299/jmtl.2.90

DOI： 10.1299/jmtl.3.380_references_DOI_ZWjPzNZqKHnuUB5DuAJzWwoRaji

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Increasing number of traffic accident in stopping at intersection caused by the aged drivers has become one of the traffic accident characteristics. This paper aims to propose an information assistance system for elderly drivers who show the unsafe behavior in stopping at intersection. The goal of this research is mainly to clarify a strategy for designing the information assistance method by analyzing the perception and recognition performance of each driver during driving. Finally, this paper demonstrates the effectiveness on enhancing the safe behavior in stopping at intersection by using driving simulator and real vehicle.

DOI： 10.11351/jsaeronbun.40.1605

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I10466705

Publisher：Informa UK Limited  

In a previous study, we developed a force-detecting interface to operate an electric wheelchair for persons with muscular dystrophy. However, the force input method of the interface tends to be directly influenced with respect to disturbance caused by road surface conditions. We proposed a disturbance removal method to detect users’ intentions using experimental results on the roads, where shocks or vibrations are experienced. Moreover, because of the structure of the electric wheelchair, the vehicle behaviour may easily become unstable due to disturbances such as the caster behaviour and the shape of the road (bumps and slopes). When an user's intended input differs from the vehicle's behaviour (brought about by these disturbances), the user has the burden of revising the command to the wheelchair. We proposed the longitudinal stability control system for the wheelchair utilising an in-wheel-motor system to improve the vehicle stability with respect to environmental disturbance.

DOI： 10.1080/00423110801958584

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

An evaluation method is difficult to design a vehicle demension in order to improve the usability of ingress-egress. In this paper, from movement of the waist and hip joint in egress and ingress, the characteristics of physical workload of the pelvis-circumference are clarified. The authors have proposed an evaluation method by estimation the each part o joint moment in place of the evaluation of measuring the muscles of the pelvis-circumference. The experiments are carried out using mock-up of passenger car to verify the effectiveness of the proposed method of workload estimation in egress and ingress from vehicle dimensions.

DOI： 10.11351/jsaeronbun.39.4_147

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I9601707

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

The study aims to classify aged drivers into several groups based on their driving characteristics. Such categorizing will be useful both for development of driver assistance syatems and for driver education. We classified them depending on their driving behavior nad background(physical and lifestyle) data. We also proposed quantitative classification method using driving parameters gained through driving simulator. Linear discriminant analysis showed it is possible to classify them into four groups with correct rete 79%. After varification of the method, the paper tried to apply it to driver assistance systems as one of examples using driving simulator.

DOI： 10.11351/jsaeronbun.39.4_141

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I9601699

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

In recent years, the number of traffic accident shows gradual decreasing in severe injuries, whereas increasing the total number of accidents. It is necessary to investigate the drivers' behaviors in intersections since many traffic accidents occur in the area. During yellow light at signalized intersections, drivers occasionally fall into dilemma either passing through the intersection or stopping at stop-line. In this paper, using the drive recorder equipped vehicle, many incident data that occurred during yellow light has been investigated. Using the collected data, actual dangerous zone during yellow light is extracted. Because the zone is one of the targets for accident prevention, the obtained understandings are useful in considering measures for enhancing safety.

DOI： 10.11351/jsaeronbun.39.6_277

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I9741330

Language：Japanese   Publisher：Society of Biomechanisms  

This paper describes development of a brain-computer interface for severe ALS patients. The BCI has high potential to make useful communication aids for the severe ALS patients who don’t have any motor functions. However, these are few products in practical use for the ALS patients because most of the developments of the BCI system are based on technical seeds and interest. In this project, interview investigations were conducted with the ALS patients at the first stage of the development. According to the result of these investigations, a concept of the BCI system was built as P300 based interface using audible stimulation with Japanese letters. This system allow us to select a letter from Japanese 50 hiragana letters with three steps by choosing one letter from five letters. Experiments with able-bodied people and ALS patients showed possibilities that this system can be practical for communication with the severe ALS patients.

DOI： 10.3951/biomechanisms.19.197

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Publisher：MDPI AG  

<jats:p>This article describes the scope of vehicle dynamics control application on micro-scale electric vehicle for enhancing its active safety. The use of in-wheel-motor control in various control objectives as active safety devices are stated in the paper. In the first half of the paper, the control systems for enhancing vehicle dynamics are described. The active front steering by using steer-by-wire mechanism for improving vehicle handling and stability is mainly presented. The latter half of the paper presents the control system designed for driving assist system. The lane keeping control with torque distribution strategy is described. The theoretical controller design and experimental validation are shown in the paper</jats:p>

DOI： 10.3390/wevj1010244

DOI： 10.20965/jrm.2015.p0005_references_DOI_8zz1Iki7Z4hrustQT7vLLHaLj89

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Language：Japanese   Publisher：東京 : 自動車技術会  

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I8908451

Publisher：Springer Berlin Heidelberg  

Even if some adjustment is provided, it is still harder for disabled people to use the joystick to operate the wheelchair although they can move their bodies. There is considerable difference in disabled characteristics among individuals. To deal with this difficulty, clarifying each person's characteristics and understanding one's individual characteristics are important issues for the proposal of their operation systems. This paper aims to propose the new operation interface, which generates no stress in operation, considering the physical characteristics among those who feel difficulty in operating with joystick. The subject for system validation is set to be a man who has Becker's muscular dystrophy as patient.

DOI： 10.1007/978-3-540-73333-1_38

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Publisher：SAE International  

DOI： 10.4271/2006-01-1186

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Language：Japanese   Publisher：東京 : 自動車技術会  

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Publisher：Informa UK Limited  

This article presents the alternative lane keeping control strategy with direct yaw moment control (DYC) that utilizes the transverse driving torque distribution. With the sophisticated structure of today's electric vehicle, the small-size motor can be placed into each driving wheel so that the DYC input can be easily and precisely achieved by controlling the in-wheel-motors independently. The information of road position is acquired by vision system via CCD camera and on-board image processing system. As a feature of the proposed system, the lateral deviation detected by CCD camera is converted into the desired yaw rate for tracing the desired lane. Then, the yaw moment control input is theoretically determined to achieve the desired yaw rate from the viewpoint of vehicle dynamics. This article presents the theoretical analysis of lane keeping control characteristics using linear vehicle model on planar motion, and experimental study using micro-scale electric vehicle to verify the effectiveness of the proposed strategy.

DOI： 10.1080/00423110600870006

DOI： 10.9746/jcmsi.13.23_references_DOI_1vak0p94tg1lhJdAxKbc75eKG8W

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

This paper examines the feasibility of Direct Yaw-moment Control (DYC) in the context of lane keeping system. The DYC, which is generated by differential traction force distribution, is designed with consideration of the road image information to assist the driver's steering maneuver for lane keeping task. Consequently, the controller is designed to regulate the lateral deviation based on the lane marker position acquired via CCD camera with on-board image processing system. The effectiveness of the proposed control system was verified by actual driving test with micro electric vehicle equipped with two independent in-wheel-motors for generating DYC.

DOI： 10.1299/kikaic.72.795

DOI： 10.1299/kikaic.77.114_references_DOI_Zsm8mbKnAaCxSWHkHPyQjPTlk6e

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

For reducing traffic accidents by aged drivers, researches on active and passive safety technologies and driver characteristics have been carried out. however, several research achievements are not so effective for aged drivers since the characteristics of aged drivers are distinguished from normal drivers and difficult to analyze. In order to clarify the distinguished factor of aged drivers, this report is based on the assumption that aged drivers' driving characteristics are strongly related to both their lifestyle and physical characteristics. The driving characteristics, the lifestyle, the physical characteristics are investigated from several questionnaire surveys followed by experiments, by using reaction test and actual driving test. The evaluation method of aged drivers' driving performance is proposed based on lifestyle and physical characteristics, and this method provides useful suggestions for understanding the aged drivers' driving characteristics.

DOI： 10.1299/kikaic.71.2790

DOI： 10.1002/ecj.12049_references_DOI_GTBeCugutX8ImfcWNhFpGupslsf

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The disabled can acquire driving licenses, if they have physical ability to transfer from wheelchair to car seat, and also to drive it with steering wheel, even if it requires any special supporting devices. However, transferring to a vehicle and driving with a steering wheel are very difficult tasks for people with severe disabilities such as damage on the cervical vertebrae, and therefore they are not able to acquire driving licenses. As a result, they do not have any mobility tools other than powered wheelchairs, which means their traveling ranges are limited. If they use automobiles that they can get on easily from their wheelchairs, and they can drive by joystick instead of steering wheel, it is greatly expected that their quality of life must be raised. This paper proposes such type of vehicle named EVD, and design of prototype and examines its feasibility and effectiveness.

DOI： 10.1299/kikaic.70.2435

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I7076774

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Powered wheelchair is a useful mobility tool for severely disabled people. However, due to its limited maximum speed of 6 km/h, life style of such people as well as their activity area are limited to close area of their residence. If they use automobiles that they can get on easily from their wheelchairs, and they can drive by joystick instead of steering wheel, it is greatly expected that their quality of life must be raised. This paper discusses on the development of the control system, which aims to make the disabled manipulate vehicle more safely, based on the concept of our past studies dealing with joystick driving. In order to lower the price of the newly developed vehicle, the design of one-person-ride motorcycle class proto-car is presented here. Among these topics, however, the design method of manipulating system is mainly discussed in this paper.

DOI： 10.1299/kikaic.70.2940

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I7131872

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

This study proposes new control systems to improve running stability of micro scale electric vehicle by using electric motor. Electric motor has the following merits : fast response compared with both an engine and a hydro-mechanical actuator, easy controllability of torque and formulation of torque characteristic, small and high power. These merits make it more feasible to implement traction control system on electric vehicles than conventional vehicle powered by engines. In this paper, traction control system based on LQI control theory is proposed for electric vehicles. The controller is designed with the objective to follow the disired relative velocity between the wheel and the vehicle body, instead of slip ratio as the conventional method. Finally, the effectiveness of the proposed controller is verified by the computer simulation and experiment that uses small scale electric vehicle with in whell-motors.

DOI： 10.1299/kikaic.70.1680

DOI： 10.1541/ieejias.130.430_references_DOI_GBTuaoN7WJCA3ZCl9M6FLlITUZ4

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DOI： 10.1016/s0389-4304(03)00044-4

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Because of the current air pollution problems in large cities, it is expected that low emission vehicles (LEV) such as electric vehicles or hybrid vehicles will be popularized. However, the following facts are impeding the popularization of LEV : (1) the vehicle cost is very high, and (2) it is not always clear how to control the traction force to achieve the best performance of the power unit. As a way to reduce the development cost, this study proposes a virtual running environment simulator, instead of chassis dynamometer, to evaluate the total indoor performance of LEV (including HEV). A parallel hybrid electric vehicle is considered in this paper, and a model matching method is used for the traction force controller design which compensates the slow response of the gasoline engine by controlling the electric motor effectively. Computer simulation and the Hardware-in-the-Loop simulator based on full vehicle model are carried out to verify the control effect on driving performance as well as the effectiveness of the controller.

DOI： 10.1299/kikaic.67.3829

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Because of the current air pollution problems in large cities, it is hoped that low emission vehicles such as electric vehicles or hybrid vehicles can be popularized. There are two main types of hybrid vehicles, series and parallel. The series type is basically an electric vehicle which uses an internal combustion engine to charge the battery for the electric motor. By using both a gas-powered engine and an electric motor is increased substantially to the point where comparatively little gasoline is required to run the gas-powered engine. The paralles type vehicle is different from the series type in that it uses the gas-powered engine as well as the electric motor to drive the vehicle. In this case it is important to effectively use both the electric motor and gas-powered engine to drive the vehicle. In this research a model matching control is used to effectively control both the traction forces. The effect of using this controller on the engine running performance and effectiveness are studied.

DOI： 10.1299/kikaic.66.1116

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Language：Japanese   Publisher：Institute of Industrial Science The University of Tokyo  

The infrastructure-cooperative automated driving systems has garnered significant interest as a potential avenue for the expeditious social deployment of Level4 automated driving. While demonstration tests have been conducted for cooperative automated driving in limited situations, the development of comprehensive guidelines for the evaluation of the entire cooperative system is a crucial step towards its implementation in a wide range of regions. Once the impact of the integration of diverse functions and the variability in the performance of each function within a cooperative system is fully definite, it will be possible to devise a cooperative system that should be implemented and to set the ODD for cooperative automated driving. This study presents the methodology along with the case example.

DOI： 10.11188/seisankenkyu.77.59

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Publisher：SCITEPRESS  

DOI： 10.5220/0013389400003912

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Publisher：IEEE  

DOI： 10.1109/sii58957.2024.10417174

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Publisher：IEEE  

DOI： 10.1109/sii58957.2024.10417710

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Publisher：Springer Science and Business Media LLC  

<title>Abstract</title> There are high expectations for autonomous personal mobility vehicles (PMVs) to support the mobility of older people. Autonomous navigation systems are being developed to assist mobility in public areas with mixed pedestrian traffic, such as airports and shopping malls. For autonomous navigation of PMVs, achieving both efficiency and comfort is important. In this study, we focused on the characteristic of passenger tolerance, in which a passenger’s discomfort is relatively small concerning an approaching pedestrian. The objective was to propose an efficient and comfortable autonomous navigation method considering the characteristics of passenger tolerance. First, the passenger tolerance characteristics were clarified through data analysis of a previous study’s dataset and a newly collected dataset. Next, a path planning method considering the characteristics was proposed, and the proposed method was evaluated by numerical simulations. The evaluation results showed that the proposed method can achieve efficient and comfortable autonomous navigation, especially in crowded environments.

DOI： 10.21203/rs.3.rs-3825758/v1

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Language：Japanese   Publisher：公益財団法人 国際交通安全学会  

DOI： 10.24572/iatssreview.49.1_78

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Publisher：IEEE  

DOI： 10.1109/smc53992.2023.10394392

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Language：Japanese   Publisher：International Association of Traffic and Safety Sciences  

DOI： 10.24572/iatssreview.48.1_4

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Publisher：SCITEPRESS - Science and Technology Publications  

DOI： 10.5220/0011802800003417

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DOI： 10.5220/0011804900003417

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DOI： 10.5220/0011698200003417

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-22K12284/

Language：Japanese   Publisher：Institute of Industrial Science The University of Tokyo  

Inactivation and decline of the rural or suburban areas by aging and depopulation have been clearer in the current Japan, which has become a super aging society. It is said that it is partly because inconvenience of short-range mobility causes the situation. The authors show that micro-EV (electric vehicle) cars are convenient for the daily short-range use in such areas shown above. We brought several micro-EV cars into a rural area near Tokyo, and we will show the situation and results with them. Theoretical conditions that make the micro-EV’s installed without problems are shown at the same time.

DOI： 10.11188/seisankenkyu.75.105

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Smooth navigation, which is consisted of efficiency and comfort, is important for autonomous mobility scooters. Efficiency can be regarded as the shortness of time the vehicle requires to reach the destination. In a previous work, the theory of situation awareness was applied to the passenger’s comfort recognition. Based on the theory, the passenger was considered to recognize comfort according to not only the recognition of the current situation, for example, the distance between the vehicle and the nearest pedestrian, but also the prediction of the future status. In this paper, passenger’s tolerance was considered as relatively smaller discomfort against close pedestrians. The characteristics of this tolerance was investigated by analyzing data of the previous work and conducting a participant experiment. The results revealed situations that the vehicle can refrain from avoiding approaching pedestrians. Based on the results, design requirements of a path planning method for smooth autonomous navigation were set.

DOI： 10.1299/jsmermd.2023.2a1-c24

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DOI： 10.5220/0012474600003660

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DOI： 10.5220/0010849700003124

DOI： 10.20965/jrm.2024.p0918_references_DOI_17dZiGgpUbKB0MU6iPWaYsUNLzS

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Language：English   Publisher：Society of Automotive Engineers of Japan, INC  

In this study, the influence of traffic environment on collision risk assessed by driving behavior indices of right turns at intersections were investigated. A driving simulator (DS) experiment and a risk simulation using the data obtained in the DS experiment were performed to investigate the influence. As a result of the investigation, the influence of the traffic environment on the relationship between the driving behavior indices and collision risk was clarified. Moreover, factors related to the influence, and a solution to consider the influence in risk assessment methods were discussed.

DOI： 10.20485/jsaeijae.13.1_21

DOI： 10.20485/jsaeijae.14.1_1_references_DOI_K1AVI94Qn4wy6FclYyyaE41vZcN

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In order for autonomous personal mobility (PM) and pedestrians to coexist in the same pedestrian space, it is important for pedestrians to accept the PM when avoiding and passing each other. When passing each other, pedestrians decide their actions based on the behavior of the PM. Therefore, in this study, the avoidance behavior of pedestrians was investigated by experiments in cases against a pedestrian and a PM. The relation between pedestrians’ behavior and pedestrians’ acceptability was also investigated by the experiments. Results showed that avoidance-starting distance and passing interval affect pedestrians’ acceptability. Based on the results, requirements of a path planning method considering pedestrians’ acceptability was set.

DOI： 10.1299/jsmermd.2022.1p1-e04

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Passenger comfort needs to be considered in the autonomous navigation of mobility scooters in pedestrian space. Previous works have shown that passenger comfort is affected by vehicle vibration and acceleration, and there are methods considering them. However, pedestrians are expected to exist continuously in large-scale facilities such as shopping malls, and it is not clear what factors may affect comfort in such space. Therefore, manual driving paths of mobility scooters were focused on in this study as paths comfortable for the passenger. The characteristics of the paths were investigated by analyzing paths collected with a driving simulator. Analysis results showed that scooter users tend to move in a free direction with no pedestrians, and paths with this characteristic was comfortable for the passengers. Based on the results, a design requirement of a path planning method for autonomous navigation in pedestrian space considering passenger comfort was set.

DOI： 10.1299/jsmermd.2022.1p1-e05

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

This study investigates an autonomous navigation method for personal mobility vehicles that is comfortable for passengers and can be used in crowded pedestrian spaces such as airports and shopping malls. Requirements for comfortable autonomous navigation were defined based on the characteristics of situation awareness related to comfort examined in our previous study, and a comfortable autonomous navigation method considering these requirements was proposed. The proposed method was evaluated by a numerical simulation and an experiment using a VR simulator to evaluate passenger comfort during autonomous navigation. The simulation and experiment results showed that the proposed method satisfies the requirements and can improve passenger comfort during autonomous navigation.

DOI： 10.1299/jsmermd.2022.1p1-e06

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Autonomous wheelchairs are expected to help older people to transport. A previous research about autonomous driving on rough terrain, which is one of the road environments where wheelchairs are used, could not jugde traversability accurately. On the other hand, though rough terrain was not examined in any detail, another research developed a motion planning method based on traversability judgement, considering the vehicle model and road surface that causes fatal accidents during the use of wheelchairs. The purpose of this research is to develop a road surface map generation method for motion planning of autonomous wheelchairs on rough terrain. In this paper, we used visual odometry method for self-localization, and found that road surface map generated has a large error when meandering on rough terrain. By correcting self-localization based on visual odometry method with the use of IMU and vehicle speed, the error of the road surface map reduced.

DOI： 10.1299/jsmermd.2022.2p2-l09

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Publisher：IEEE  

DOI： 10.1109/robio54168.2021.9739581

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Publisher：MDPI AG  

<jats:p>In Japan, the aging population is expected to increase the number of elderly people in the future. The purpose of this study was to develop a hip lift transfer assistive system to improve the QOL of elderly living and to prevent back pain for caregivers. We extracted the impediment factor and the necessary scene for the assistance, decided on the transfer process from the wheelchair in the toilet, and considered the reduction method of the burden based on the quantitative evaluation of the caregiver’s lumbar burden and developed the device. Then we proposed the algorithm of the system by grasping the behavior and lumbar burden characteristics at the time of using the hip lift transfer assistive system by the developed device in which the proposed support algorithm of standing seating assistance operation is implemented in the actual use environment. Through the assistive movement evaluation experiment and the actual operation in the toilet, we have verified that the use of this device can reduce the caregivers’ lumbar burden below the standard value (3400 N) and have proved the effectiveness of the proposed transfer assistive system.</jats:p>

DOI： 10.3390/s21227548

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20J10461/

Publisher：ACM  

Autonomous navigation systems for powered wheelchairs are drawing attention to support older adults in moving outdoors. It is important to evaluate how the users behave and feel when they experience autonomous navigation for their development. VR-based simulators are used to evaluate user's behavior and subjective assessment in various scenarios without putting anybody at risk. However, it is difficult to reproduce realistic motion feedback in the simulator using motion platforms. Moreover, this physical feedback influences user's perception of self-motion, which affects their behavior and feeling. In this paper, we proposed a novel simulator that gives real motion feedback while simulating various scenarios by combining a virtual reality headset and a real powered wheelchair. Experiment results showed that subjective assessment of comfort during autonomous navigation differed between the proposed simulator and a simulator without motion feedback, indicating that perception of the wheelchair's behavior was enhanced by real motion feedback.

DOI： 10.1145/3473682.3480257

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Publisher：IEEE  

Driving behavior modeling (DBM) is widely used in the intelligent vehicle field to prevent accidents, which predicts actions that vehicles should take to optimize safe driving behaviors. According to some statistics, accidents easily happen at un-signalized intersections. Modeling driving behavior at such places is of great importance. However, current inverse reinforcement learning-based DBM methods fail to predict proper behaviors at the un-signalized intersections in the aspects of smoothness and stopping behavior by just using a single Markov decision process (MDP). We propose a novel sequential MDPs approach to model the driving behavior at the un-signalized intersections to solve the problems. Our approach decomposes the target behavior through the un-signalized intersections into three parts and models each decomposition's driving behaviors with appropriate time durations by a stopping-time-interval distribution through dynamic programming. Experiments on real driving data show that the proposed method achieved a better result and successfully improved the smoothness and stopping awareness of the planned driving path compared to the baselines.

DOI： 10.1109/iv48863.2021.9575851

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Publisher：Research Square Platform LLC  

<jats:title>Abstract</jats:title> <jats:p>During the autonomous locomotion of personal mobility vehicles (PMVs) in pedestrian space, it is necessary to avoid collisions with pedestrians walking nearby. The avoidance paths of the PMVs are affected by the behavior of the pedestrians, which may also affect passenger comfort. In this study, a local path planning method considering passenger comfort is proposed to design comfortable pedestrian avoidance strategies during autonomous locomotion of PMVs in pedestrian space. First, pedestrian behaviors that affect passenger comfort are investigated by evaluating the comfort in pedestrian avoidance scenarios with different avoidance methods and pedestrian behavior. Next, requirements for a pedestrian avoidance method considering comfort are set based on the behaviors affecting passenger comfort. Finally, a novel path planning method satisfying the requirements is proposed. It is confirmed that the proposed method can generate comfortable paths in pedestrian space, and the validity of the proposed method is examined by a subject experiment.</jats:p>

DOI： 10.21203/rs.3.rs-298102/v1

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Publisher：IEEE  

Autonomous driving of a personal mobility vehicle such as a wheelchair in a walking space is crucial as a means of transportation for the elderly and the physically handicapped. To realize this, accurate pedestrian detection is indispensable. As existing 3D object detection methods are trained with a roadway dataset, they are widely used for object detection in roadways. These methods have two major drawbacks as regards the detection of objects in walking spaces. The first is that they largely depend on the different LIDAR models. To eliminate this issue, we propose a 3D object detection method, CosPointPillars, that does not take the reflection intensities of the LIDAR point cloud, which causes a sensor model dependency, as input. The second drawback is that networks trained with a roadway dataset cannot sufficiently detect pedestrians (who are major traffic participants in walking spaces) located within a short distance; this is because the roadway dataset hardly includes nearby pedestrians. To solve this issue, we generated a new walking space dataset called SimDataset, which includes nearby pedestrians as a training dataset in the simulations. An experiment on a real walking space showed that SimDataset is suitable for use in pedestrian detection.

DOI： 10.1109/icpr48806.2021.9413329

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Publisher：MDPI AG  

<jats:p>Detection of traversable areas is essential to navigation of autonomous personal mobility systems in unknown pedestrian environments. However, traffic rules may recommend or require driving in specified areas, such as sidewalks, in environments where roadways and sidewalks coexist. Therefore, it is necessary for such autonomous mobility systems to estimate the areas that are mechanically traversable and recommended by traffic rules and to navigate based on this estimation. In this paper, we propose a method for weakly-supervised recommended traversable area segmentation in environments with no edges using automatically labeled images based on paths selected by humans. This approach is based on the idea that a human-selected driving path more accurately reflects both mechanical traversability and human understanding of traffic rules and visual information. In addition, we propose a data augmentation method and a loss weighting method for detecting the appropriate recommended traversable area from a single human-selected path. Evaluation of the results showed that the proposed learning methods are effective for recommended traversable area detection and found that weakly-supervised semantic segmentation using human-selected path information is useful for recommended area detection in environments with no edges.</jats:p>

DOI： 10.3390/s21020437

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DOI： 10.5220/0010348800890100

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetld.2021.30.ps2-9

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Japan has been a super-aging society since 2007. The authors proposed a small four-wheeled vehicle along a concept called “NNC” suitable for such a society as Japan. The abbreviation “NNC” is after the initials of the following words, Narrow, Near and Current. A vehicle along the concept is about up to 1m wide and 2.5m long, tandem for two passengers, only for neighborhood business and can join the road traffic flow of ordinary cars. Vehicles by the NNC concept will be a new mobility device not a car nor a bicycle, which can be helpful for elderly drivers, mothers in childcare and can improve the structures of urban cities and rural areas.

DOI： 10.1299/transjsme.21-00090

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The objective of this research is to develop autonomous mobility adaptable to the pedestrian environment with indistinct road boundaries using a recommended traversable area detection system. In previous research, we proposed a learning method for weakly-supervised semantic segmentation, which was effective in improving the performance of detecting recommended traversable areas. In this paper, we developed an autonomous navigation system based on a driving recommendation map using a recommended traversable area detection system. By setting appropriate weights to consider recommended traversable areas, generating paths in the direction of right and left turns while suppressing path generation to non-recommended areas was achieved. Also, by adding a new class of driving trajectory and sidewalk area, the system can selectively enter sidewalks in scenes where physical features and edges cannot be taken. Finally, the usefulness of the developed system in a real environment with indistinct road boundaries was verified.

DOI： 10.1299/jsmermd.2021.2p1-b13

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

We have been developing an inverted pendulum type robotic wheelchair with the ability to climb stairs. This wheelchair has a seat slider and two rotary links between the front and rear wheels on each side. It is controled by a linear-quadratic regulator consisting of a center of gravity control mode and a rotary link control mode. In this paper, we focus on how to estimate the modeling errors in using this system and how to suppress the wheel motion, because modeling errors caused by payloads can cause the wheelchair to fall. We found that modeling errors cause wheel movement due to errors of the slider position and changes of the mass of the passenger. We proposed a method for estimating the slider position error and mass change, and confirmed that the method can be applied to correct the error.

DOI： 10.1299/jsmermd.2021.2p1-j11

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In order for autonomous personal mobility(PM) and pedestrians to coexist in a pedestrian space, it is important for them to be able to avoid and pass each other smoothly. Studies suggest that it might be possible for PM and pedestrians to pass each other within a short time without compromising comfort by understanding how pedestrians react to the behavior of PM and use it in the autonomous locomotion. Therefore, in this study, the avoidance behavioral characteristics of pedestrians was investigated by experiments, and a path planning method that enables smooth passing was developed based on these characteristics. Result shows that by using the characteristics of pedestrians’ cognition against PM it was able to develop a smooth autonomous locomotion.

DOI： 10.21203/rs.3.rs-1215934/v1

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Publisher：IEEE  

The wheelchair is the major means of transport for elderly and physically disabled people in their daily lives. However it cannot overcome architectural barriers such as curbs and stairs. In this study, we developed an inverted-pendulum-type robotic wheelchair for climbing stairs. The wheelchair has a seat slider and two rotary links between the front and rear wheels on each side. When climbing up stairs, the wheelchair rotates the rotary links while maintaining an inverted state of a movable body by controlling the position of the center of gravity using the seat slider. In previous research, we proposed the control method for climbing up stairs using the rotary links and seat slider, confirming a period of approximately 5 s to rotate the rotary links. In this paper, we propose a control method for going down stairs, and experimentally verify the control effectiveness and stability.

DOI： 10.1109/iros45743.2020.9341242

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Publisher：IEEE  

Automated driving technology enhanced with automated mobility scooter is expected as a transport support for vulnerable elderly and disabled people. It is necessary to have a mobility strategy that can improve the safety, comfort, and acceptability of users for social implementation of automated mobility scooters. In this study, we specifically focus on the comfort of users. The hypotheses that the velocity of mobility scooters and the density of peripheral pedestrians will affect the comfort of users in automated driving and that it can be quantitatively evaluated by using their physiological responses were tested. The environment in which the mobility scooters and pedestrians move around together was reproduced using a driving simulator. The psychological and physiological responses of users during automated driving were investigated and recorded. The results showed that density of pedestrian affect the valence of users, and suggested that the possibility of quantitative evaluation of the user’s affect by using physiological measures.

DOI： 10.1109/itsc45102.2020.9294542

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Publisher：MDPI AG  

<jats:p>Individuals with severe physical impairments have difficulties operating electric wheelchairs (EWs), especially in situations where fine steering abilities are required. Automatic driving partly solves the problem, although excessive reliance on automatic driving is not conducive to maintaining their residual physical functions and may cause more serious diseases in the future. The objective of this study was to develop a shared control system that can be adapted to different environments by completely utilizing the operating ability of the user while maintaining the motivation of the user to drive. The operating characteristics of individuals with severe physical impairments were first analyzed to understand their difficulties when operating EWs. Subsequently, a novel reinforcement learning-based shared control method was proposed to adjust the control weight between the user and the machine to meet the requirements of fully exploiting the operating abilities of the users while assisting them when necessary. Experimental results showed that the proposed shared control system gradually adjusted the control weights between the user and the machine, providing safe operation of the EW while ensuring full use of the control signals from the user. It was also found that the shared control results were deeply affected by the types of users.</jats:p>

DOI： 10.3390/ijerph17155502

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DOI： 10.5220/0008966201620169

DOI： 10.13140/rg.2.2.11190.24648

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

This paper proposes a new mechanism for an inverted pendulum type robotic wheelchair with the ability to climb stairs. This mechanism is developed to improve occupant safety and comfort. First, physical analysis confirmed that the proposed method met the purpose of ensuring the safety of the occupants. Next, the dimensional requirements necessary to develop the mechanism were clarified , and the mechanism was actually designed and manufactured. Finally, the operation was actually confirmed using the manufactured mechanism ,and problem were extracted

DOI： 10.1299/jsmermd.2020.2a1-n04

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

One of the problems in a super-aging society is to secure transportation for the elderly. To solve the issues, the authors focused on electric mobility scooters that is one of the personal mobility. The purpose of this research is to develop the autonomous driving system of electric mobility scooters for realizing safe transportation and new mobility services. This paper describes the introduction of traversable area judge methods in the walking environment the authors proposed. And, demonstration experiment field that simulated the walking environment prepared is also described.

DOI： 10.1299/jsmermd.2020.2a1-a12

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

During autonomous locomotion of personal mobility (PM) in pedestrian space, it is necessary to avoid collisions with pedestrians walking nearby. Avoidance paths of the PM is affected by the behavior of the pedestrians, which may also affect the comfort of the passengers. Therefore, in this study, the behavior of pedestrians affecting the comfort of the passengers during autonomous locomotion was investigated by experiments, and a path planning method for pedestrian avoidance considering comfort was proposed considering the behavior of pedestrians. Simulation results showed that comfortable paths that avoid uncomfortable situations can be generated, and the possibility of improving the comfort of passengers was shown by subject experiments.

DOI： 10.1299/jsmermd.2020.1p2-c13

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Language：English   Publisher：Japan Society for Simulation Technology  

Individuals with severe disabilities typically suffer from lack of muscle power and deformation of their hands. This significantly affects their ability to operate an Electric Wheelchair (EW) especially when using joystick controllers because one operation of a joystick affects both the straight and turning motions of an EW. Thus, individuals with severe disabilities typically exhibit difficulties in operating an EW, especially in the cases that require fine steering capabilities. In contrast to autonomous driving, the study proposes a novel shared control method using reinforcement learning considering utilizing users' residual physical functions. With the use of online learning, the shared controller provides proper assistance based on the driving environments and each user's input characteristics. The effectiveness and the characteristics of the novel shared controller are discussed via simulations.

DOI： 10.15748/jasse.7.300

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Language：Japanese   Publisher：公益財団法人 国際交通安全学会  

DOI： 10.24572/iatssreview.43.3_125

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Publisher：The University of Iowa  

The objective of this study is to clarify the relationship between the speed anticipation characteristic with optical flow derived from self-motion and driver behavior of older drivers for future driver assessment. We focused on speed anticipation with optical flow because anticipated speed is assumed to influence behavior at unsignalized intersections with limited visibility, which is an accidentprone situation for the older drivers in Japan. To assess the characteristic, we constructed a novel test by revising a similar test. We conducted an experiment with older drivers that consisted of the novel test and an on-road driving test. The experiment results showed that the speed anticipation characteristic with optical flow had a significant effect on older drivers’ behavior at intersections and drivers who anticipated speed faster drove slower and safer.

DOI： 10.17077/drivingassessment.1708

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

We have been developing an inverted pendulum type robotic wheelchair with the ability to climb stairs. This wheelchair has a seat slider and two rotary links between the front and rear wheels on each side. It is controled by a linear-quadratic regulator consisting of a center of gravity control mode and a rotary link control mode. This paper focuses on a method for restraining movement of wheels when it climbs stairs more quickly because this movement causes fall of the wheelchair. We grasped that the movement was caused by forces acting on pitch angle, such as inertial force and reaction of driving force. We proposed a control method considering dynamic equilibrium of the attitude and confirmed the effect of restraining wheels’ movement by applying the method.

DOI： 10.1299/jsmermd.2019.2p1-a15

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In recent years, there has been a several number of researches in the field of self-driving system using electric wheelchairs. However, in most researches it must need to construct maps in advance for navigation. Therefore, we proposed an automated driving system for mobility scooter without mapping in advance. In this paper, we use semantic segmentation to classify traversable area on forward camera images into three classes based on human’s judgements, and apply the images to the system that can classify them online using SegNet. By matching a classified image and point clouds from the stereo camera and updating the cells of the map using binary bayes filter, it generates a traveling recommendation degree map of road surface for mobility scooter. To navigate the mobility scooter, we use Hybrid-State A* Search to search a drivable route based on the traveling recommendation degree map, and use Dynamic Window Approach to calculate the actions for following the planned path. The experimental results showed that the proposed system achieved autonomous navigation.

DOI： 10.1299/jsmetld.2019.28.2016

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Publisher：IEEE  

As the aging society in Japan intensifies, the demand for caregiver is also increasing, but many back pain problems have been reported which should be solved during the transferring. In order to improve the QOL of elderly people in elderly welfare facilities and prevent back pain of nursing care workers, we aimed to develop a kind of transfer assist equipment depend on the investigated elderly facilities and extracted requirements. In addition, we focused on the burden on waist and upper limbs during human assistance transfer, devised a method to reduce the burden based on quantitative evaluation and developed the equipment. On the other hand, fixation of the knee joint of the care recipient, assist equipment that can carry out raising and lowering of the seating surface according to the intention of the caregiver was developed, and the effect of reducing the burden on the waist of the transfer operation by using the transfer assist equipment was verified.

DOI： 10.1109/robio.2018.8665301

DOI： 10.3390/s21227548_references_DOI_5wzeKQXdiBOLW9PyxUIe6BlJuWk

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Publisher：Elsevier BV  

Traffic accident statistics in Japan show the necessity of preventing vehicle-on-pedestrian accidents. If the risk of a vehicle colliding with pedestrians could be evaluated in advance, driver-assistance systems would be able to support drivers to avoid potential collisions. Here, features of driving behavior and methods for assessing the risk of collision were investigated for a right turn at an intersection in left-hand traffic, which is a typical vehicle-on-pedestrian accident scenario. The results showed that pedestrian-collision risk can be evaluated from how the driver slows the vehicle and where the driver looks while turning during the maneuver. Moreover, pedestrian-collision risk could be predicted based on driving behavior upon commencement of steering when making an across-traffic turn. Keywords: Risk assessment, Driving behavior, Pedestrian collision, Across-traffic turn

DOI： 10.1016/j.iatssr.2018.02.001

DOI： 10.20485/jsaeijae.13.1_21_references_DOI_9uRhgLjWvfDIGeRGGfTxM2GZk5k

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Publisher：IEEE  

Driver drowsiness is one of the most causes of traffic accidents worldwide. To prevent such accidents, it is necessary to detect driver drowsiness as early as possible. In previous studies, it was confirmed that decreasing arousal levels affect physiological indices, behavioral indices, and driving performance. The goal of this study is to classify the alert states of drivers, particularly the slightly drowsy state, based on physiological indices, behavioral measures, and driving performance. First, the relationship between the arousal level of a driver, physiological signals, such as electroencephalogram and electrocardiogram signals, behavioral measures, and driving performance is investigated based on analysis of data measured by a driving simulator (DS) and driver monitoring system. Next, to classify the alert and the slightly drowsy states utilizing machine learning algorithms, a total of 32 features are extracted from the measured data over a period of 10 seconds. Four machine learning algorithms, namely logistic regression, support vector machines, the k-nearest neighbor classifier, and random forest (RF), are utilized for the classification of driver drowsiness in this study. As a result, it is confirmed that the RF method can obtain up to 81.4% accuracy when distinguishing between alert and slightly drowsy states. This result demonstrates the feasibility of driver drowsiness detection based on hybrid measures over a 10-second time period with high accuracy.

DOI： 10.1109/itsc.2018.8569493

DOI： 10.20485/jsaeijae.13.2_83_references_DOI_XDnXA3ZAzm8wgjOqKZVYqrVvjpd

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Publisher：IEEE  

Persons with severe disabilities experience difficulties in operating an Electric Wheelchair (EW) due to their lack of muscle power and the deformation of their hands. Even special input devices are developed to meet their physical limits, there is no guarantee that they can operate the EW correctly as they intend. To deal with this, EW needs to add more or less intelligence. Unlike autonomous driving, shared control can not only improve the operation but also keep users’ residual physical function and improve their enthusiasm. However, it is always a difficult problem to decide the control weights between user and machine to meet the requirements that making full use of users’ operating abilities and giving assistance when necessary. In this paper, we propose a novel online learning shared central system that can adjust the central weights considering users' motivation, safety and social adaptabilities by online evaluating users’ operating ability. Simulation results show the validity of the proposed method.

DOI： 10.1109/hfr.2018.8633469

DOI： 10.15748/jasse.7.300_references_DOI_Otqd88SMwDAfWRH5dTGrA0BhUtW

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Language：Japanese   Publisher：東京 : 三井住友海上福祉財団  

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

We are studying an inverted pendulum type robotic wheelchair with the ability of climbing stairs. The structure of the wheelchair consists of a seat slider and two rotary links between the front and rear wheels on either side. As the control, we used a linear-quadratic regulator consisting of a center of gravity control mode and a rotary link control mode. This work is focused on method for restraining movement of wheels when it climbs stairs, which causes fall of wheel chair. We grasp the mechanism the movement is caused by mutual interference behavior between wheel and rotary links in climbing stairs. We proposed two methods for decreasing interference behavior by changing the target track of rotary links and confirmed the effect of restraining movement of wheels.

DOI： 10.1299/jsmermd.2018.1p2-g06

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Population of elderly people are growing in Japan and maintaining their independent living is an important issue. The number of mobility scooters, which supports short-distance locomotion of the elderly and help them maintain their independence, are increasing and becoming more common. However, traffic accidents involving mobility scooters are occurring and the accidents include fatal accidents. Therefore, we aim to construct a low-speed mobility system which secures safe locomotion of the elderly with an autonomous locomotion function installed in a mobility scooter. Mobility scooters can travel inside pedestrian space, because they are regarded as pedestrians. For autonomous locomotion in pedestrian space, safety which can be interpreted as no collisions with the surrounding pedestrians, is one of the most important factors to be considered. However, riding comfort and time required for locomotion are also important factors. In this research, we examined an autonomous motion planning method which improves comfort and smoothness of locomotion respectively while ensuring safety, mainly for mobility scooters used by elderly people. For improvement of comfort, we proposed a trajectory planning method which restricts vehicle behavior with large acceleration and jerk. For improvement of smoothness, we proposed a method which enables the vehicle to follow other pedestrians. Considering the two proposed methods, we constructed an autonomous motion planning method and evaluated the effectiveness with numerical simulation. The simulation results revealed that each proposed method increased riding comfort and smoothness of locomotion respectively without decrease in safety.

DOI： 10.1299/jsmetld.2018.27.1111

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

This report describes a modeling method for predicting a pedestrian walking route in stochastic manner. In our previous research, we derived probability distribution functions of walking speed and angle at local area based on the walking experiment. However, it seems that a pedestrian determines own avoidance route using the information on the distance to the obstacle. The avoidance angle is one of the most important parameters. In this report, the avoidance angle is modelled as a function of distance L. As a result, it made easy to estimate the avoidance angle at an arbitrary location. The effectiveness of the method is examined by comparing the predicted locus with real walking one.

DOI： 10.1299/jsmermd.2018.1p2-b08

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Publisher：IEEE  

The aim of this study was to estimate the road surface shape in a grassy area in order to judge whether a mobility scooter can drive without accidents. For drivability evaluation, a road surface shape map is needed and it is constructed by a laser range finder (LRF). In order to make an accurate road surface shape map, it is necessary to obtain distance information of the road surface accurately. An experiment was conducted to understand characteristics when acquiring distance information in a grassy area. It was found that the distance information obtained from the LRF in a grassy area may include the information of the road surface. Therefore, we proposed a new road surface shape map expressed by the probability of being a road surface. An experiment was carried out to verify the validity of the proposed road surface shape map. It was found that the accuracy was sufficient for drivability evaluation.

DOI： 10.1109/sii.2017.8279299

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

To prevent fall accident that occur when elders use mobility devices in pedestrian space, a driving assistance system is required. The objective of this research is to clarify the requirements for such system and construct a driving assist system based on requirements. First, we extracted environmental elements which causes fall accident from mobility scooter’s drive recorders and recorded the driving environment and user’s operation. Among the environmental elements, we especially focused uneven roads which cause failure in prospecting vehicle motion for users. We propose a driving fall risk evaluation method based on prospecting vehicle motion at prospective waypoint by calculating positions of the wheels using an elevation map. We verified the effectiveness of the proposed method in uneven road using a mobility scooter.

DOI： 10.1299/jsmetld.2017.26.1203

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Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Towards prevention of traffic accidents involving pedestrians, the objective of this study is to construct a pedestrian collision risk assessment method of right turn at intersections for driver assistance systems based on driving behavior indices related to drivers’ risk anticipation. In this paper, we first clarified traffic environment elements affecting right turn driving behavior and classified typical patterns of pedestrian collision scenes. Next, we focused on car-following right turn scenes as a case study and examined driving behavior indices regarding drivers’ risk anticipation and validated the indices through a risk scene reproducing experiment using the JARI-ARV.

DOI： 10.11351/jsaeronbun.48.915

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This paper describes a modeling method for predicting a walking route of a pedestrian in a stochastic manner. We consider one of the most typical situations where a pedestrian walks along to a sidewalk, and then some obstacle exists in front of the pedestrian. To represent the walking route of the pedestrian during the avoidance action, a stochastic model is suitable than deterministic one. The stochastic model is derived from the walking experiment where a pedestrian avoids some obstacle in natural walking. Based on the loci obtained from the experiment, the pedestrians walking speed and walking direction at any local area was approximated by Gaussian and Beta distribution function, respectively. As a result the walking route of a pedestrian can be represented in a stochastic manner. The estimated output of the model is examined by comparing with two real walking loci that were obtained from near-miss incident database. One examination scene is avoidance of a parked vehicle, and the other is of parked bicycle on the roadside. By the numerical simulation, we obtained the results that the both real walking routes are included within the 3-sigma ranges of the estimated output of 500 trials.

DOI： 10.1299/transjsme.17-00224

DOI： 10.1299/mej.23-00490_references_DOI_MRh2o4543PnH2pcdMgHOQPmWTjG

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This report proposes a modeling method for predicting a pedestrian walking route in stochastic manner. To represent pedestrian motion in naturally, a stochastic model is suitable than deterministic one. The stochastic model is derived from the walking experiment where a pedestrian avoids some obstacle in natural walking. Using the loci obtained from the experiment, we first represent the walking speed and walking direction at local region in the form of histogram. Then we approximate the histogram by continuous distributions. As a result, we obtain the stochastic model representing the natural motion of a pedestrian. The effectiveness of the proposed method is examined by comparing the predicted locus with real walking one.

DOI： 10.1299/jsmermd.2017.2p2-d11

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Language：Japanese   Publisher：Japanese Association for an Inclusive Society  

DOI： 10.18975/jais.19.1_55

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetld.2017.26.3003

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In the development of an automatic driving system of mobility scooters, a traversable area detection method in the range of about 10m where position accuracy can not be guaranteed by GPS is important. We propose a traversable area detection method that can perform advanced traversable area recognition using semantic segmentation. Semantic segmentation classifies images into several meaningful classes on a pixel by pixel basis. Therefore, we make data set classified objects on the forward image into three classes based on the judgment criteria of traveling recommendation, and constructed a system that can classify objects online using SegNet. By matching a classified image with point cloud of a stereo camera and updating a cell of the traversable recommendation degree map by bayesian filter, it is calculated how much traveling is recommended for mobility scooters on road surface. We tested the system in a road scene. As a result, it was found that plausible traversable area can be obtained by the proposed method.

DOI： 10.1299/jsmetld.2017.26.3007

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

We are studying an inverted pendulum type robotic wheelchair with the ability of climbing stairs. The structure of the wheelchair consists of a seat slider and two rotary links between the front and rear wheels on either side. As the control, we used a linear-quadratic regulator consisting of a center of gravity control mode and a rotary link control mode. This work is focused on method for preventing fall of wheelchair when it contacts with the step. We grasp the mechanism that the fall is caused by the external force received from the side of step. We proposed a method to compensate for the attitude angle moment by the command value of the rotary link torque and confirm the effect of preventing the fall.

DOI： 10.1299/jsmermd.2017.1p2-e10

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Control of thermal factors is needed to improve the conditions of occupants, because the thermal factors affect the conditions of occupants such as the comfort sensation, arousal level which is related to task performance. To determine the control method of thermal factors for improving the comfort sensation and the arousal level, indices which can evaluate the comfort sensation and the arousal level quantitatively and continuously are necessary. In this study, we focused on the physiological indices such as EEG (Electroencephalogram) which reflects the activity of central nervous system and ECG (Electrocardiogram) which reflects the activity of autonomic nervous system, and aimed to clarify the relations among the arousal level, thermal comfort and the parameters of EEG and ECG. We recorded the EEG, the ECG, the subjective feelings of thermal comfort and facial expression for evaluating arousal level of 14 healthy young males while they performed arithmetic tasks in environmental conditions that room temperature changed. From the results, among the parameters of EEG, there are indices that reflect the changes in arousal level only and other indices that reflect the changes in both arousal level and thermal comfort. On the other hand, among the parameters of ECG, there are indices that reflect the changes in both arousal level and thermal comfort.

DOI： 10.1299/transjsme.16-00516

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Language：Japanese  

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Language：Japanese   Publisher：[東京] : タカタ財団  

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I028389079

Publisher：IEEE  

Indoor thermal quality affects not only a person's perception of comfort, but also their level of arousal, work performance and health. Therefore, it is important that thermal factors are controlled and that a thermal environment is designed in accordance with its purpose. In this study, we aim to design a thermal environment that improves both the arousal level and thermal comfort of the occupants. In order to confirm the possibility that changes in thermal factors can improve both the arousal level and thermal comfort, we investigated the relationships between the physiological parameters, subjective sensation, and the performance of tasks. Specifically, we directed participants to perform a mathematical task and an evaluation of subjective sensation relating to their comfort level and arousal level. Simultaneously, the physiological indices of the participants such as their skin temperature and respiration rate were measured, and tests such as electroencephalography (EEG) and electrocardiography (ECG) were conducted throughout several conditions of changes in the thermal factors. Through the results of our study, we confirm that the relationship between comfort sensation and arousal level corresponds to changes in the thermal factors, we carried out a quantitative and continuous evaluation of a person's comfort sensation and arousal level using physiological indices.

DOI： 10.1109/smc.2015.169

DOI： 10.1299/transjsme.16-00516_references_DOI_Tk1n0A1id7831EWbMcfe1aHMblh

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This paper shows posture control strategy of an inverted pendulum type wheelchair on undulations such as small step or wave shape road. That wheelchair equipped with a seat slider, two wheel linkage and four wheels and its structure enable it to climb stair automatically. To keep seat in a horizontal position, based on road surface shape measuring with laser range sensor, desired slider displacement is set to maintain body pitch posture angle and desired each side wheel linkage angle are set to maintain body roll posture angle. To realize desired parameter, two degree of freedom control which consist of feed forward input and feedback input is constructed. Feed forward input is decided based on the kinematic equation calculated by the 3 dimension rigid body link model of wheelchair. Feedback gain change depending on wheel linkage angle and calculated by linear quadratic regulator (LQR) method. The effect of proposed posture control is demonstrated by comparing it with control without feed forward on a physical dynamic simulation.

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

When people go out with those babies, they use baby carriages. However, when handling the baby carriage, the baby riding on the baby carriage is affected badly by vibration excited by roads, and parents operating the baby carriage also feel uncomfortable and tired because of vibration. In this paper, it was investigated whether the vibration, which was a problem for babies and parents from the point of view of frequency and mode shape, can be excited, and reduction methods of vibration excited at the seat of baby carriages were suggested. It was revealed that resonance frequency agrees with the frequency which affects babies at the seat, and it was inferred that the vibration of the handle was caused by the one of the baby carriage whole. The reduction methods of vibration were also suggested. The best method of vibration reduction of the seat was guessed to connect the top of the seat to the point which hardly vibrates.

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

This study proposes a collision avoidance tactics for micro vehicles (MV) at medium or small-sized intersections which are not controlled with traffic signals. An empty space would be found in this tactics based on the geometric shape at the intersection and it moves MV into the space to avoid a crossing vehicle. The avoidable speed of the MV will be calculated based on the estimation of the existence of crossing vehicles before the crossing vehicle is not detected.

DOI： 10.1299/jsmetld.2015.24._1415-1_

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Publisher：IEEE  

The authors describe a mechanical design and control strategy for an inverted pendulum type robotic wheelchair. The structure of the wheelchair consists of a seat slider and two rotary links between the wheels and tires on either side. In addition, the integrated control is based on a linear-quadratic regulator consisting of a gravity-center control stage and a wheel-linkage control stage for climbing stairs. The authors verified the effectiveness of the control system and the mechanical structure on a physical dynamic simulation. The authors present an overview of the kinematic structure and control strategy for climbing stairs.

DOI： 10.1109/arso.2014.7020991

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Age-related decline in cognitive function is one of the causes of traffic accidents of scooter. Therefore, it is important to develop an education system considering cognitive ability of scooter users for reducing the occurrence of such accidents. It is necessary to clarify the relationship between cognitive ability and driving behavior of elderly drivers for developing said education system. This paper proposes a new user coaching system using touch panel screen device based on a naturalistic driving behavior database stored by drive recorder. We found the possibility that elderly scooter users can drive safely by improving the abilities of risk-compensation strategies.

DOI： 10.1299/jsmetld.2014.23.221

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Some commercial types of the pure electric vehicle (PEV) have been on the market of Japan a couple of years before. It, however, is found some insufficient points in the time of battery charge and its cruising range, etc. on the current PEV which can get the customers decline their purchase. This presentation will show a new chart called "Charge boundary chart" which can be used to consider the uses and charge performance of PEV at the same time.

DOI： 10.1299/jsmetld.2014.23.219

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To prevent accidents with road crossing pedestrians, we analyzed the road crossing behavior of pedestrians using the near-miss videos and data. Thus we extract that the pedestrians are not aware of the approaching vehicles as a factor of dangerous crossing. To evaluate the possibility of collision, we modeled the crossing scene and organized the conditions that the collision could not be avoided by braking of the vehicle when the pedestrian unaware of approaching vehicles crossing. In such a condition that it is difficult for the vehicle to avoid the collision, we proposed informing the approach of the vehicle to pedestrians as one measure of collision avoidance.

DOI： 10.1299/jsmetld.2013.22.191

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In this study, we reveal the fact that the passenger's movement on the vehicle inverted pendulum in going up and down stairs cause the movement of wheels and the overturning happens. To avoid the overturning, we add the slider control depending on the passenger's mass position to the controller. In case the new controller is insufficient in safety, we suggest the additional ways. One way is the append of new actuator which prevent wheels from moving. The other way is the change of the gain on feedback control in accordance with the passenger's mass velocity and acceleration. Additionally, we consider the method of ascending and descending stairs to fulfill the safety and comfort.

DOI： 10.1299/jsmermd.2013._2p1-r18_1

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Based on the analysis of elderly driver's actual driving behavior, we classified unsafe driving behavior into 4 categories by focusing the consciousness and the intent. By extracting the causes of unsafe driving behavior, we develop quantitative index to discriminate the consciousness and the intent at an intersection where vehicles must stop temporarily on entering. Results of the experiments show the clarified that the maximum velocity and uneven reaction speed are selected as the quantitative index. Moreover, it is verified that 76.6% of the driving behavior about the consciousness and the intent were discriminated by the index.

DOI： 10.1299/jsmetld.2013.22.223

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Publisher：University of Iowa  

The objective of this study is to propose indices that detect deviated states of drivers during driving considering their judgment process and using a road environment and natural driving behavior database. To this end, the authors focus on curved roads because as road curvature changes continuously drivers need to adapt their behavior to not go wide of the lane or the road. The drivers’ speed choice behavior around curve situations was focused upon, and a speed choice process was formulated. Moreover, the validity of the formulated speed choice behavior in curve situations was examined using the real vehicle and the simulator.

DOI： 10.17077/drivingassessment.1475

DOI： 10.20485/jsaeijae.10.1_106_references_DOI_LKsELEPSlz0hmm6Fz1yBq8fCggW

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Language：Japanese   Publisher：Society of Biomechanisms  

Some assistive technologies for persons with dementia have been developed to facilitate awareness of information by providing the information visually. However, these technologies have been evaluated by subjective assessment and learning process, and their effectiveness in daily life has not become clear yet. The purpose of this study is to investigate the effectiveness of such assistive technology including the process of familiarization and utilization for a person with dementia. A four month clinical evaluation of a daily-plan indicator was conducted using the field-based method. Results of a user’s speech and behavior analysis showed that the ratio of information awareness was increased from 50 to 97 after six week of use and 100% after four months of use respectively. The ratio of independence in information awareness had also increased from 0 to 57%. The use of vivid colors was found to be helpful for increasing the use of the indicator.

DOI： 10.3951/sobim.37.58

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Various micro-electric vehicles (EV) have been made by a lot of manufacturers in the world since approximately two decades before. Few numbers of such small cars, however, have come into use in Japan. This is mainly because the proper utilities have not been considered sufficiently while the micro-EV's would not be substitutes for the ordinary cars including "Kei (Light)" class cars in Japan. The micro-EV's can be very useful transfer method when their characteristics or their essentials are considered enough. Several kinds of prototypes of micro-EV's made by the authors are shown in this paper and the prototypes have various utilities as maintenance service in the woods in the suburban areas, picking-up a member of a family to hospital and mothers' transfer with children more than one, etc. The benefit of such prototypes is verified at the same time that the functions of them are not provided for the ordinary cars.

DOI： 10.1299/jsmetld.2013.22.233

DOI： 10.1299/transjsme.21-00090_references_DOI_8YRpdsHJ3VecgivzCAU1CYPtBh8

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Publisher：IEEE  

In this paper, we describe the motion control for a personal mobility robot (PMR) that is a wheeled inverted pendulum vehicle. The structure of the PMR consists of a seat slider and two independent leg wheels attached on either side; this enables the driver to mount the PMR by changing the vehicle's height from the squatting position to the standing position. In addition, this structure can control the roll posture of the vehicle and thus prevent the PMR from toppling over because of a short tread. The seat slider facilitates a stable pitch posture with suitable control. We present an overview of the kinematic structure, three-dimensional dynamics model, and control method based on the linear-quadratic regulator (LQR), in order to achieve stable control of the PMR.

DOI： 10.1109/iros.2012.6385572

DOI： 10.1109/roman.2014.6926221_references_DOI_WnAajbLhT9gpJjDybK6ChuPcei7

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Based on the analysis of elderly driver's real driving behavior, we classified unsafe driving behavior 4 categories by focusing the consciousness and the intent. By extracting the causes of unsafe driving behavior, we propose two effective education methods. One is the method to have students grasp their own driving behavior objectively. The other is the method to raise their safe driving consciousness. We verified the effect of these education methods. To classify the characteristics about an elderly driver's educational, we made an experiment that compares the educational effect of the elderly drivers and the young drivers.

DOI： 10.1299/jsmetld.2012.21.257

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To evaluate the possibility of collision in the driving environment of handle type electric wheelchairs, we suggested the collision predictive index based on the analysis of the video image data of driving handle type electric wheelchairs and examined the validity of it in comparison with the risk perception data obtained from expert sales persons. By using this index, we can quantitatively evaluate the possibility of collisions with pedestrians, bicycles and the rushing out from blind spots. As a result of examination of validity, we found that the collision predictive index could correctly identify 63% of objects within the range of the scenes we analyzed.

DOI： 10.1299/jsmetld.2012.21.237

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Publisher：IEEE  

Gaze estimation is a key technology to understand a person's interests and intents, and it is becoming more popular in daily situations such as driving scenarios. Wearable gaze estimation devices are use for long periods of time, therefore non-active sources are not desirable from a safety point of view. Gaze estimation that does not rely on active source, is performed by locating iris position. To estimate the iris position accurately, most studies use ellipse fitting in which the ellipse is defined by 5 parameters(position (x,y), rotation angle, semi-major axis and semi-minor axis). We claim that, for iris position estimation, 5 parameters are redundant because they might be influenced by non-iris edges. Therefore, we propose to use 2 parameters(position) introducing a 3D eye model(the transformation between eye and camera coordinate and eyeball/iris size). Given 3D eye model, projected ellipse that represents iris shape can be specified only by position under weak-perspective approximation. We quantitatively evaluate our method on both iris position and gaze estimation. Our results show that our method outperforms other state-of-the-art's iris estimation and is competitive to commercial product that use infrared ray with respect to both accuracy and robustness.

DOI： 10.1109/iccvw.2011.6130505

DOI： 10.1109/tvcg.2015.2391857_references_DOI_DilMIWE5HuEwn3CsoHXs0HNUkDX

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Publisher：Springer Berlin Heidelberg  

In an aged society, easy-to-use information devices are necessary. In order to develop information devices which elderly adults can use easily, it is important to bring out characteristics of elderly adults in using information devices based on their cognitive functions. In this study, the authors focus on a relation between memory function and exploration behavior in a hierarchical menu while learning process. An experiment is conducted with eight elderly adults and eight young adults. In this experiment, a hierarchical menu composed based on the library classification, not actual hierarchical menus, is used in order to eliminate differences of knowledge about information devices between elderly and young adults. As a result, it seems that decrease of episodic memory increases a possibility of improper selections in the hierarchical menu when doing the same operations as previous operations.

DOI： 10.1007/978-3-642-21741-8_10

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Traffic accidents involving elderly drivers are major concerns in Japan. Age-related decline in cognitive function is said to be one of the causes of these accidents, so it is important to propose driving support system considering cognitive ability to reduce these accidents. It is necessary to clarify the relation between cognitive ability and driving behavior of elderly drivers for developing driving support system. We recorded the driving acts of elderly drivers and examined the relation between cognitive ability and unsafe driving act.

DOI： 10.1299/jsmetld.2011.20.39

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In Japan, nearly 5,000 people have been dead by traffic accident in a year. Especially, the number of traffic accident for pedestrians resulting in death is the highest. Thus, active safety technologies to ensure the safety for pedestrians are strongly required. In this study, main cause and accident induced mechanism of pedestrian to vehicle collision at signalized intersections are investigated utilizing incident database. In general, a signalized intersection is relatively safe area when both pedestrian and driver obey rule coordinated by traffic signals. However, the incident analysis shows that the number of near-miss at signalized intersection is still high. A characteristic data analysis which defines pedestrians' disobedience action to signal gives instructive result for near-miss induced mechanism at signalized intersections.

DOI： 10.1299/jsmetld.2011.20.15

DOI： 10.1299/transjsme.18-00419_references_DOI_Ou8e9v9Tgc8Zo0jDYcB7JFsce21

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In this study, the detection of the inattentiveness state is discussed. If this detection becomes possible, and a driver assistance system which leads a driver to normal state from deviated inattentiveness state is realized, it could prevent the unsafe driving behavior and consequently prevent traffic accidents as well. To propose the indices to detect the inattentiveness state, we focus on the eye movement while driving. The objective of this paper is to extract the feature of the eye movement in the inattentiveness state while driving in the urban area. Especially, we analyzed the relationship between the road environment and the eye movement while driving with the inattentiveness state by using driving simulator and actual vehicle. The result showed that the driver eye movement with the inattentiveness state influences the gazing time and the gazing object.

DOI： 10.1299/jsmetld.2011.20.277

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