On on-orbit passive object handling by cooperating space robotic servicers

Space exploitation will require efficient techniques for manipulating passive objects on-orbit. This work presents a manipulation technique that utilizes both on-off thrusters and manipulator proportional forces to handle passive objects on orbit, canceling the effect of limit cycles on the objects. The system dynamics including the unilateral constraints and the on-off thrusting are discussed. Using a two-layer optimization process, a planning strategy for the trajectory tracking motion of a passive object including optimal end-effector contact point selection, is developed. The manipulation strategy is illustrated using a 3D scenario. A model-based controller adapted to the special characteristics of the system is presented and its response is discussed. The performance of the proposed manipulation system is shown to be promising, while it reduces excessive thruster fuel consumption.