Adaptive Terminal Sliding Mode Control of Space Manipulators Actuated by Control Moment Gyroscopes

An adaptive nonsingular terminal sliding mode (ANTSM) control method is proposed for trajectory tracking control of space manipulators actuated by scissoredpair control moment gyroscopes (CMGs). Equations of motion are derived by means of recursive algorithms based on Kane’s equations. The nonsingular terminal sliding surface with the tracking error as the variable is constructed to ensure that the tracking error converges to zero in finite time on the sliding surface. The adaptive laws are also proposed for the control gain’s adjustment on account of the uncertainties of the system quality characteristic parameters and unknown disturbances. The control method does not need to know the upper bounds of the uncertainties and the closed loop system is uniformly ultimately bounded. Simulation results verify the effectiveness of the proposed controller combined with the accuracy of tracking expected trajectory and the robustness on the inertia parameter uncertainties and disturbance torque of joints.