非駆動自由度軌道計画法を応用した構造可変型4輪ロボットの高速段差昇降制御

抄録

In this paper, we propose a control method of dynamic passing over steps for a wheeled robot whose center of gravity is high. We are developing a wheeled robot called a ‘variable structure type four-wheeled robot’ which, with a simple structure, has ability to pass over a step. Though this robot has only one degree of freedom for changing the body's structure, it can run on four wheels like a car or on two wheels like a wheeled inverted pendulum. We already proposed a method by combining the transfer from 4- to 2-wheeled mode and the transfer from 2- to 4-wheeled mode to perform an experiment of passing over a step whose height is larger than the radius of the wheel successfully. However, it took about 60 seconds to step up or down in this way because there were four changes of control modes in the procedure. Therefore, we propose a dynamic trajectory control method to make passing over a step speedier. We plan two kinds of dynamic trajectories throughout stepping up. One is the trajectory to realize softlanding at the exchange of the contacting wheel from rear to front. The other is the trajectory considering the collision with the step surface in landing to make stepping smoother and speedier. As the result, we have successfully realized an experiment of stepping up and down by this robot in only two seconds.