トルクセンサを用いた介助型パワーアシスト車椅子の開発

Abstract

This paper describes a power-assisted attendant-propelled wheelchair employing a model reference control algorithm based on velocity feedback control. The model equation encompasses two parameters, mass and viscous damping factor. The input of the control system is operator's force. Choosing the model mass less than the real value enables the operator to move the wheelchair with less effort. The goal is to realize functionality where the operator would always feel as though he/ she were propelling a lighter wheelchair on level ground.In order to measure the operator' s force we developed a propelling force sensing mechanism utilizing magnetostrictive torque sensors. The control circuit uses a16-bit single chip microcomputer and DC motor driver boards. The model parameters were chosen through experiments on surfaces indoors. Test drives with dummy weight(65kg)on surfaces indoors and slopes to buildings, and so on were conducted. Both young adults and elderly people took part in the tests. The results shown by the subjects indicate that they started the wheelchair with less than half of the force required when they operated a normal wheelchair. Adaptations of the parameters to the operator' s characteristics and to situations such as quick start or slow stop are to be solved.