Attitude And Position Control Algorithms Based On Terminal Sliding Theory Research For Satellite

Satellite Formation flying is a key technology for the space missions of the future, as aformation of a satellite will be doing the job as a single satellite with high precision andflexibility. It can complete many space and Earth science missions, such as distributedaperture radar, enhanced stellar and extension planet detection optical interferometry,virtual coobservation and stereo-imaging platforms for space science, and Earthobserving. The challenge this technology facing is in controlling the position andorientation of a different satellite with respect to a satellite which is the known as themaster satellite of the formation of satellites. There are a lot of interference coupledwith satellite’s own uncertainty which increases the difficulty of attitude and positioncontrol. In this dissertation, the attitude and position control algorithms are deeplystudied for the problem of relative attitude and position in satellites formation.Firstly, we study the motion model of the satellite, in order to study better thecontrol of relative attitude in satellites formation, the single satellite model is built, onthat basis the relative attitude motion model for Leader-follower satellite formationflying is derived, at last nonlinear relative dynamics to model the follower relativemotion with respect to the leader is obtained.Secondly, a terminal sliding mode attitude controller for single satellite is proposed.A new sliding mode is developed, make a deep analysis for the singular problem, and anonsingular terminal sliding mode is brought to avoid singular. Numerical simulationsfor proposed control algorithms are performed for proving the designed controller’srobustness under the system interference and uncertainty.Thirdly, we use the nonlinear relative attitude dynamics to model the followerrelative motion with respect to the leader. Terminal sliding mode controller for leaderand follower are designed, in particular, the control algorithm for follower is obtainedon the base of relative attitude motion model. Each algorithm, analyzed by Lyapunovstability theory, can achieve the desired attitude tracking in finite time.Finally, aiming at the problem of maintaining the relative position of satelliteformation, the nonsingular terminal sliding mode control law is designed. A nonsingularand fast terminal sliding is brought to solve the slow-convergence problem of theexisting nonsingular terminal sliding mode control. Numerical simulations for proposedcontrol algorithms are performed for proving the designed controller’s validity andfeasibility.