Autonomous Step Climbing Strategy Using a Wheelchair and Care Robot

This report describes a cooperative step climbing strategy using an electric wheelchair and autonomous robot. The robot, which was developed by our research group, has a wheeled travel mechanism and dual manipulators. The wheelchair is a commercially available model modified with added sensors, circuits, and batteries. When the wheelchair and robot encounter a step, the robot grasps the wheelchair and they help each other to ascend the step. In the step climbing process, the wheelchair front wheels are lifted using the difference between the wheelchair and robot velocities, and the front wheels are placed on the step. To make the rear wheels of the wheelchair climb the step, the robot upper arms push against the back of the wheelchair, which is like the motion of man pushing a wheelchair up the step. Similarly, the robot front and rear wheels climb the step using assistance from the wheelchair. We developed an automatic control system that realizes the cooperative step climbing of the wheelchair and robot and also simplifies the operation of both vehicles. An experiment was conducted to demonstrate that the wheelchair and robot can successfully maneuver up a step.