Abstract
This paper is concerned with the dynamics of mobile robots with a three-wheel cluster. The mobile robot with three-wheel cluster can travel on flat floor by rotating each wheel, and can ascend and descend stairs by rotating a wheel cluster hub. This makes the robot to be able to move around in various environment, and the control strategy would be applicable to powered wheel chairs which can ascend and descend stairs. In this paper, we consider only the dynamics of the robot in the sagittal plane. The dynamics of the mobile robot has the single-wheel mode in which the robot should be dynamically stabilized, and the double-wheel mode in which the robot is statically stable. Furthermore, switching between these modes involves collisions of a wheel and a stairstep, and the velocity jump in motion of the robot occurs. We have derived the dynamics and the switching conditions of the mobile robot with a three-wheel cluster. Furthermore, we propose a control strategy for the robot ascending and descending.
