Disturbance Attenuation Control for Power-Assist Wheelchair Operation on Slopes

This paper proposes a practical and effective disturbance attenuation control algorithm to support the safe and comfortable operation of power-assist wheelchairs. The power-assist wheelchair is an option for mobility that can be propelled by the user´s arm while also providing additional assisting torque based on the measured user torque to relieve the user´s propulsion effort. The control algorithm proposed in this paper detects external forces other than the applied human torque and attenuates the effect of the external force to improve safety and ease of use. The proposed 2-D disturbance attenuation control can reduce the effect of external force in the longitudinal direction and the rotational direction respectively. Gravity on slopes is considered the major disturbance, and the effectiveness of the proposed controller on slopes is verified by experiments.