Passivity-Based Tracking Control of a Planetary Rover With Robotic Arm

Kurzfassung

Nowadays, rovers play an important role in the exploration of our nearest celestial bodies. These planetary exploration missions include both locomotion and manipulation tasks, involving physical contact situations in an unstructured environment. The requirement of increasingly autonomous task execution promotes task-space control, particularly robust and reactive control approaches. Therefore, we propose a passivity-based whole-body tracking control law for a wheeled planetary exploration rover equipped with a robotic manipulator. The control approach achieves compliant trajectory tracking at the end-effector. At the same time, a corresponding platform trajectory is computed along with the torque control law, which enables whole-body reactive behavior and obviates the need for dedicated platform trajectory planning. Moreover, an extension of the control law to the regulation of a static configuration of the end-effector at the end of the trajectory is proposed. We validate the presented control approach with experiments on a prototype of a planetary exploration rover. The results show that the total tracking error at the end-effector is about 2.2 times smaller using the platform velocity controller than using platform torque control.