Relative position and attitude coupled control based on modified twisting algorithm

Abstract:

The relative position and attitude coupled second-order sliding mode controller is proposed by combining twisting algorithm with linear compensator for on-orbit servicing to a non-cooperative target spacecraft. On the basis of a coupled relative motion model between docking ports on two spacecrafts, the modified twisting controllers with linear compensation items are designed by using two different sliding surfaces. A strict Lyapunov function is proposed to prove that the modified twisting controllers have the property of finite time convergence for bounded perturbations and the upper bound for the time convergence is estimated. Simulation results are presented to validate strong robustness of the proposed second-order controllers for model uncertainties and limited perturbations with the comparison with the standard twisting algorithm. The chattering alleviation and attenuation is also achieved in actuating mechanism.