Capacitor regenerative braking control of power-assisted wheelchair for safety downhill road driving

This paper describes a capacitor regenerative braking control scheme of electric power-assisted wheelchairs for safety driving on downhill roads. The “electric power assisted wheelchair” which assists the driving force by electric motors is expected to be widely used as a mobility support system for elderly people and disabled people; however, it has no braking system to suppress the wheelchair´s velocity and brings the dangerous and fearful driving especially on downhill roads. Therefore this paper proposes a novel safety and efficient driving control scheme based on the capacitor regenerative braking system. This study applies the regenerative braking system with the step-up/down chopper circuit with additional resistance and realizes the velocity feedback control with the variable duty ratio so that it tracks the smooth velocity based on Minimum Jerk Model. In addition, the reference velocity is flexibly designed according to the declined angle. Some driving experiments on the practical downhill roads show the effectiveness of the proposed control system.