Variable Geometry Tracked Unmanned Grounded Vehicle - Model, Stability and Experiments

This paper introduces an originally designed tracked robot. This robot belongs to the VGSTV (Variable Geometry Single Tracked Vehicle) category. It is equipped with two tracks mounted on an actuated chassis. The first joint is used to articulate the chassis and the second one to keep the tracks tightened. By controlling the chassis joint it becomes possible to adapt the shape of the tracks to the ground and even to release the tracks in order to pass through specific obstacles. A prototype has been build ; technical specifications and dynamic model are presented in this paper. Tele-operated experiments have been conducted and have shown that the stability of the robot have to be addressed. We experimented and compared two classical criterions based on the center of mass and on the zero moment point technique. Experimental results are discussed in the case of a staircase clearing.