Stability Analysis and Control of Tethered Space-Tug System

Space debris is the space junk produced with the launch of human spaceflight, which poses a great threat to the safety and reliability of space environment. In order to curb the growth of space debris and maintain the stability of space environment around the earth, active debris removal is the only choice. Among all techniques proposed for active debris removal, the tethered space-tug (TST) concept may be one of the most promising techniques with advantages of light weight, high flexibility, simplicity in controller design, and tolerance to debris shape. In this study, the space debris TST system is taken as the research object. In combination with engineering practice, the space debris is towed to the grave orbit by constant tension. The dynamics model of TST system was established, and the system stability is proved by Lyapunov method, the attitude nutation of space debris is restrained by using the constant tension switching control law, the control law based on phase plane control principle is proposed to stabilize in-plane and out-plane swing of tethered combination, the simulation results show that the control law can achieve the expected control effect.