Control of Space Manipulator Using Slliding Mode Control

This paper proposes a method for controlling a space manipulator with an end-effector for grasping a satellite floating in space. The previously published methods have two problems, (1) they have not dealt with the case where a satellite-manipulator-target system has translational and rotational momenta, and (2) they need much calculation when an end-effector linearly approaches a target's grasping point. We applied a sliding mode control method, and the first problem was resolved by considering momenta as external distubrances and the second problem was dealt by considering the exponential convergence of errors. And we proved a practical stability of the control which means that relative errors can be suppressed within a planned sphere in a finite time (for a case where angular velocities of the manipulator arms were controlled) . This control scheme uses observed data obtained on-board the spacecraft. Finally the practicality of the proposed method is investigated and the efliiectiveness of that is demonstrated by computer simulations.