The Attitude Tracking Control For Spacecraft And Coordination Control Based On Terminal Sliding Mode

With the high-speed development of space, China has been spending more andmore energy on the spacecraft’s control technology. In this field, attitude controlgets more and more attention. The on-orbit spacecrafts in space would be affectedby all kinds of disturbance torques, which affect the precision of tracking.Designing a control law with good performance for the system is the most important.In recent years, the technology of Satellite formation has attracted the attention ofmany countries and it has been got great development. Spacecraft formation flying(SFF) is expected to be an applicable technology for many space missions such asmonitoring of the Earth and its surrounding atmosphere, geodesy, deep spaceimaging and exploration, and on-orbit service and maintenance of spacecraft. Theconcept of SFF is to replace a large spacecraft with a group of smaller,less-expensive, and cooperative spacecraft. In particular the major advantage of SFFlies in flexibility and modularity. In view of the spacecraft attitude tracking as wellas the spacecraft formation flying, this paper mainly designed its control law.Firstly, The Euler Angle, quaternion and rotation matrix description methodswere given for the motion model of the satellite. This paper studied attitude trackingof satellite and quaternion was mainly used to describe the attitude of satellite. Theattitude tracking model was deduced. Then the model of the Spacecraft formationflying was deduced.Secondly, the terminal sliding mode surface is designed based on the terminalsliding mode theory, and then the corresponding controller was given. However,when it comes to the terminal sliding mode, we have to consider the singular of theproblem. So a non-singular terminal sliding mode was designed. Finally, asimulation experiment was given.Thirdly, based on the previous research, the uncertainty of the moment ofinertia was considered. Therefore adaptive method was adopted for this problem. ALyapunov function was chosen to prove the convergence of the systems. Numericalsimulations were used to prove the controller.Finally, the problem of distributed attitude coordination control for spacecraftformation flying was considered. A terminal sliding mode control law was proposedto cope with this problem. Numerical simulations were used to illustrate theproposed controller.