Adaptive Sliding Mode Control Law for Tethered Space Robot with Saturated Tension and Thruster Torque

Abstract

This paper presents a sliding mode control for the motion control of tethered space robot. The input saturation of tension and thrusters is well taken into account, which is dealt with by a modified adaptive law to aid the expression of ideal control input in Lyapunov-based stability analysis. The adaptive law is designed to be naturally bounded such that the boundary of adaptive law is calculable and fixed to make the ideal input bounded, which satisfies the condition of the partial expression of the ideal input. For reducing the effect from disturbance and uncertainties, the relay-type control law combined with the adaptive law is used to drive the system states onto the sliding surface although the saturation occurs. Numerical simulation illustrate the results of deployment process to verify the effectiveness of the stability analysis.