Motion control of joystick interfaced electric wheelchair for improvement of safety and riding comfort

Nowadays powered wheelchairs are widely utilized to help people's locomotion. However, many commercialized powered wheelchairs still provide unsatisfactory ride quality, which is mainly due to not-well-designed control algorithm. To address this issue, this paper proposes a motion control algorithm that can improve the safety and riding comfort of the user and can be easily implemented on a powered wheelchair. To design the controller in an intuitive way, locomotion mode of a wheelchair is suggested at first, which consists of the longitudinal mode and the rotational mode. Then, the motion reference generator, wheelchair motion observer and control algorithms are designed in this locomotion mode. Moreover, this locomotion mode-based motion control does not require encoders, which makes the implementation of the algorithm affordable for many commercialized wheelchairs. The detail of the controller and state observer is studied, and experimental results to verify the validity of the proposed controller and the state observer are explained.