A tip-over and slippage stability criterion for stair-climbing of a wheelchair robot with Variable Geometry Single Tracked Mechanism

This paper introduces an originally designed wheelchair robot equipped with a novel type of Variable Geometry Single Tracked Mechanism (VGSTM) that can actively control the robot shape and the track tension. So it becomes possible to improve the obstacle clearing capability of the robot by adapting the robot shape for the obstacle. Tip-over and slippage for track typed mobile robots are intractable problems especially in stair-climbing, which is the most fundamental obstacle clearing performance of the wheelchair robot, because of the complex track-stair interaction. In this paper, a tip-over and slippage stability criterion is derived based on the geometric model, the static model, and the track-stair interaction analysis. The stability state of the wheelchair robot during stair-climbing is obtained by simulation.