Human riding experiments on soft front wheel raising of robotic wheelchair with inverse pendulum control

Wheelchair bound persons need assistance since there are many steps in roadways or walkways. Therefore, we are proposing a robotic Wheelchair which enables a wheelchair bound person to climb over steps of up to about 8 [cm] in height without assistance. By using the proposed robotic wheelchair, a user can maintain inverse pendulum control after raising its front wheels. Then, a user can move forward to the step maintaining the inverse pendulum control, and can climb over the step using the DC motor force of rear wheel shafts. We have presented previously the front wheel raising scheme using rear wheel shaft movement. The inverse pendulum control has been conducted successfully. However, a rider on the robotic wheelchair felt a small shock since the front wheels were raised quickly. A new front wheel raising and lowering scheme is proposed in order to raise and lower the front wheels gently. The proposed scheme utilizes the rider's seat movement. The raising speed could be slowed down, and the overshoot could be decreased.