Global Terminal Sliding Mode Control of Tethered Satellites Formation with Chattering Reduction Via PID Laws

This paper researches a novel global terminal slid- ing mode control(GTSMC) on a tethered satellites system(TSS) under outer disturbances, and the effect of PI/PD compensation in restraining chattering on sliding surface is appended. By taking advantage of the finite-time convergence of traditional terminal sliding surface, the sliding surface with global and terminal sliding motion is proposed, and the convergent time by GTSMC is qualitatively evaluated by the sliding surface. Then the integral/derivative function of the low-pass filtered switching control is appended in GTSMC. By virtue of the accuracy of integral and the damping of derivative, respectively, the persisting on sliding surface is eliminated, such that the chattering effect of the controlled system on the surface is restrained consequently. Finally, simulations of the proposed control on TSS is shown to validate the theoretical analyses.