Spacecraft Rendezvous And Attitude Control System By Bounded Linear Feedback

Spacecraft is the carrier of human exploration of the universe and the execution of space missions.The study of spacecraft dynamics and control contributes to the stable and reliable operation of spacecraft in space and plays a key role in the development of space technology.As part of spacecraft dynamics and control,the success of spacecraft rendezvous is the precondition of many space missions and attitude control systems directly affect the stability of the spacecraft in orbit.With the diversification of space missions,spacecrafts meet many problems,such as extreme space environments,increasingly complex structures,bounded inputs,time delays,and time-varying features.Insufficient knowledge of these issues can lead to performance degradation and even instability of the spacecraft control system.Therefore,the research on spacecraft rendezvous and attitude control based on these problems has received more and more attention.Spacecraft system meet several important features,for example,saturation nonlinearity and time-varying parameters.The global stabilization problem of the spacecraft rendezvous by delayed and bounded linear feedback and the spacecraft attitude control problem by bounded and time-varying controls are addressed.A general problem of the global stabilization of neutral stable linear periodic system by bounded linear feedback is also considered.The following main results are given.1.The global stabilization problem of the circular orbit rendezvous system with input saturation and time-delay is investigated.By decomposing the linearized relative motion equations into a cascade of neutral stable linear systems,linear state feedback controllers are proposed in the presence of both input saturation and/or time-delay.The global stability of the closed-loop system is proved.Optimal feedback gain is also obtained in the delay-free case.2.A general problem of the global stabilization of neutral stable linear periodic system subject to bounded control is considered.By using solutions to some periodic Lyapunov matrix equations associated with the open-loop system,the global stabilization of discrete-time linear periodic system with bounded control is solved by state feedback and observer based output feedback and applied to the spacecraft magnetic attitude control system.The global stability of the closed-loop system is proved by constructing explicit Lyapunov functions.A function observer based output feedback controller for the continuous periodic system by bounded control is presented and the global stability of the closed-loop system is proved.3.The three-axis magnetic attitude control of small spacecraft with momentum bias configuration by bounded linear feedback is addressed.Based on Jordan form approach,necessary and sufficient conditions are derived to guarantee that the linearized dynamics and kinematics are neutral stable(in the Lyapunov sense).The classical criterion by analyzing the characteristic equation is improved,the repeated poles on the imaginary axis in the characteristic equation are compulsively ignored.Explicit solutions to some Lyapunov equations associated with the considered open-loop system are obtained.Based on the explicit solutions to the Lyapunov equation,both explicit bounded linear state feedback magnetic attitude stabilizing controller and function observer based output feedback magnetic attitude stabilizing controller are designed.Globally asymptotic stability of the closed-loop systems is proved by constructing explicit Lyapunov functions.4.The three-axis attitude stabilization of the axisymmetric spacecraft with bounded inputs is studied.By constructing some novel state transformations,bounded linear state feedback controllers are constructed for the considered attitude control system.By constructing suitable quadratic plus integral Lyapunov functions,the global stability of the closed-loop systems is proved if the feedback gain parameters satisfy some explicit conditions.By solving some min-max optimization problems,a global optimal feedback gain for the underactuated attitude stabilization system is proposed such that the convergence rate of the linearized closed-loop system is maximized.The attitude stabilization of the inertially symmetric spacecraft subject to bounded inputs is revisited.Bounded linear state feedback controllers are constructed to guarantee that the considered system is globally stabilized.Optimal linear feedback gain is also obtained.