Abstract
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.
