Model-based chassis control system for an over-actuated planetary exploration rover

摘要

In planetary exploration, wheeled mobile robots (rovers) are popular for extending action range compared to a lander. Despite their success, they continue to struggle with soft grounds which shows in high sinkage and can lead to an immobilization in the worst case. Rovers usually are over-actuated due to individual wheel drives and steering, which is rarely made use of in current missions. Some work optimizing the resulting degrees of freedom exists but often does not use all available model knowledge. In this work, the rover is consequently modeled with the subsystems rigid body dynamics, kinematics and wheel/ground dynamics. Feedback linearization is used for the rigid body and the underlying wheel/ground controllers on individual wheel level. The control allocation of the forces is done via the pseudo-inverse and a base of the null-space to extract the available degrees of freedom. A verification of the approach is shown in a co-simulation with a high-fidelity model of the ExoMars rover.