Autonomous Stair Ascending and Descending by Quadruped Wheelchairs

Wheelchairs are an important means of transportation for people with disabilities. However, because wheelchairs move on wheels, it is impossible for wheelchair users to move along paths such as stairs that cannot be covered by wheels, thus imposing significant limitations on their mobility. Although some wheelchairs are now available with crawler mechanisms, they cannot handle spiral staircases, in which the length of the tread differs between the inside and outside of the staircase. This paper proposes a quadruped wheelchair that can be used on all types of stairs. The proposed quadruped wheelchair is a fusion of a quadruped robot and a wheelchair, and has the potential to achieve high mobility on both plain and uneven terrain. On the other hand, it is very complicated to carry a person on the wheelchair. In this paper, we show that a quadruped wheelchair with a person on board can ascend and descend stairs using a simulator and reinforcement learning, which is a milestone toward the realization of a quadruped wheelchair.