Distributed Coordinated Tracking And Configuration Keeping Control For Satellite Formation Flying

With the development of space technology, satellite performance requirements gradually increase so that the volume, weight, and cost of one single satellite increase obviously. Satellite formation flying could not only improve the system reliability but also reduce the cost of development and maintenance. Therefore it has attracted more and more attention. This dissertation surveys recent results of satellite formation flying and investigates the distributed coordinated tracking and configuration keeping control for satellite formation systems with external disturbances and model uncertainties. Under the constraint that only part of followers can obtain the information of the dynamic leader, distributed coordinated algorithms are proposed under a directed communication topology by using Lyapunov stability theory. The main contributions of this dissertation are as follows:Three distributed coordinated tracking and configuration keeping controllers are proposed. 1) A finite-time distributed coordinated control using nonsingular terminal sliding mode scheme is proposed. It improves the robustness of the system and speeds up the convergence performance. 2) In order to reduce the chatting phenomenon, a controller is proposed, which make the closed-loop system asymptotically stable. By introducing an auxiliary variable, the discontinuous sign function is included in the first derivative of the control law. Thus, the control law obtained by integral operation is continuous. 3) A high order finite-time terminal sliding mode controller is proposed to reduce the chatting to further enhance the performance of the satellite formation system. An adaptive law is used to estimate the upper bound of system uncertainties.By considering the communication time delay problem, two finite-time distributed coordinated tracking and configuration keeping controllers are developed. A kind of distributed adaptive estimation strategy based on neural network is proposed. Another adaptive law is used to compensate the upper bound of the estimation error. Three cases of the leader are considered for the first controller: 1) static leader; 2) dynamic leader; 3) dynamic leader with a constant velocity. When the leader has a constant velocity, a distributed time delay estimator is proposed. Considering the practice environment and in order to obtain some satisfactory performances, the error constrained control is utilized. By introducing an auxiliary variable related to the constrained synchronization errors, a distributed adaptive cooperation control law by considering communication time delay is proposed.