An approach to contact detection and isolation for free-floating space robots based on momentum monitoring

In this paper, contact detection and isolation problems for a free-floating space robot are addressed. An approach based on monitoring the total momentum of the system is proposed. Indeed, in free-floating mode, no force or moment acts on the base and thus the total momentum is preserved. When a contact situation arises, the components of the total momentum change, detecting the event. Moreover, translational and rotational momentum can be exploited to identify the exact contact point. Finally, a possible extension of the approach to robots with base actuation is preliminarily discussed. The performance of the proposed strategies is assessed through numerical simulations considering a free-floating robot composed of a 3 degrees-of-freedom (DOF) arm mounted on a 6DOF moving base.