The Study Of Containment Control Methods For Micro-satellite Cluster Under Complex Information Topology

With the devolopment of space technology,large space missions,such as deep space exploration which consists of tens or up to hundreds of micro-satellites,are performed through information interaction and coordinated control of members.Parts of space missions do not require precise formation configuration for micro-satellite cluster,relative orbit and relaive attitude only need to be kept within a specific range for information links and energy transfer.For large-scale micro-satellite cluster system,multiple leaders are often adopted to ensure the ability to control cluster members.The information topology structure has significant influnce on control performance,proper information topology structure design is needed to achieve desired control performance with less energy.For the aforementioned problems,containment control of micro-satellite cluster is taken as the research background of this thesis,orbital and attitude containment control of micro-satellite cluster is studied in depth by using algebraic graph theory.The main research contents are as follows:Aiming at the mission scenarios don’t require precise attitude coordination,such as expanding observation field or searching observation target in earth observation of micro-satellite cluster.Event-triggered control strategy was introduced into attitude containment control problem.Under directed fixed topology,an event-triggered attitude containment control algorithm based on disturbance estimator is proposed in the existence of inertia uncertainties and external disturbances with known vibration frequency,triggering condition consisting of state-dependent and time-dependent function is designed to adjust control period and avoid the Zeno behaviour.The proposed attitude containment control algorithm and triggering condition could make the attitude of followers converges to the orientation formed by the leaders’ orientations.Based on the sliding mode controller’s insensitivity to external disturbances and model parameter changes,event-triggered distributed adaptive sliding mode control algorithm is designed,and sufficient and necessary conditions for the followers to enter into the orientation formed by the leaders are given.On this basis,in view of the fact that the relative angular velocity is difficult to measure,an event-triggered adaptive sliding mode control algorithm without relative angular velocity feedback is presented,so that the follower could converge to the convex hull formed by the leaders’ orientations.The simulation results show that the event-triggered attitude containment control algorithm can effectively reduce execution frequency of control tasks,as well as ensuring the follower converges to the orientation formed by the leaders.For mission scenarios such as collision avoidance in deep space exploration of micro-satellite system,distributed orbital containment control algorithm is given to control the cluster satellites to enter into the safe area formed by the leaders,the necessary and sufficient conditions for the system to exponentially converge into the safe region formed by multiple leaders are derived.Then the influence of control gain coefficients on convergence rate under undirected topology are analyzed in the case of absence of relative velocity feedback and absence of absolute velocity feedback.Specifically,the control gains which achieve maximal convergence rate are derived,the study will provide theoretical reference for how to obtain a satisfactory convergence rate using less control force and simpler information topology design for micro-satellite cluster system.Finally,graph theory is employed to investigate the influence of information topology on steady state distribution of followers,which provides theoretical basis for collision avoidance of followers with each other while converging to the safe area.For space missions with power and energy constraints such as asteroid exploration of micro-satellite cluster,event-triggered orbital containment control algorithms are proposed to reduce execution frequency of control tasks and energy cost.Firstly,centralized-triggered orbital containment control algorithm is proposed so that followers are triggered synchronously,control law is recalculated synchronously,then followers asymptotically converge to the target area formed by the leaders.Considering that the centralized-triggered control method will bring great pressure to micro-satellite cluster system,distributed-triggered orbital containment control algorithm is proposed,then followers asymtotically converge to the target area formed by the leaders.A sliding mode adaptive orbital containment control algorithm is proposed in the presence of external disturbances and mass uncertainties,so that the followers could asymptotically converge to the safe area formed by the leaders.For multiple dynamic leaders,a sliding mode adaptive orbital containment control algorithm based on desired velocity estimation is proposed to make the followers converge to the dynamic convex hull formed by the leaders.The simulation results show that the event-triggered orbital containment control algorithm can not only ensure the asymptotic convergence of the followerto the target area formed by the leaders,but also reduce the computation and energy consumption effectively.