Passive Add-On Mechanism with Rotational Dampers for Step-Down Support in Electric Wheelchairs.

This study proposes a damped add-on mechanism to mitigate the impact of an electric wheelchair on a step-down. A rotational damper is mounted on the add-on mechanism to reduce the velocity of wheel fall, thereby mitigating the impact. By selecting the damper based on a mechanical model of the wheelchair and the rider, the impact can be effectively mitigated for users with different body weights. Performance evaluation experiments confirmed that the damper could reduce the peak acceleration of the wheelchair seat when the rear wheels landed on the ground to 27% of that without the damper. In addition, nonimpaired participants in the experiment confirmed that they could climb up and down a 23 cm step and that the perceived impact was reduced. These results indicate that the damper is effective in mitigating the impact.Clinical relevance This work proposes a novel mechanism for impact mitigation during wheelchair stepdown by wheelchair end-users.