Discrete Gain Scheduling Control Design For Spacecraft Elliptical Orbit Rendezvous System With Actuator Saturation

Spacecraft elliptical orbit rendezvous has been recognized as an important mission in aerospace engineering such as space stations,space laboratories,space communication and remote sensing platforms.Successful rendezvous is a precondition for many space missions,including interception,rescue,repair,docking,large-scale structure assembly and so on.During the past few decades,many spacecraft elliptical orbit rendezvous control problems have been studied based on linear time-invariant Hill-Clohessy-Wiltshire(H-C-W)equations.However,results on linear time-varying Tschauner-Hempel(T-H)equations are rare.This is mainly because T-H equations have the time varying features such that the spacecraft elliptical orbit rendezvous control problems are much more complicated.Thus,this is the main motivation of this dissertation.This dissertation mainly studies the design problems of discrete gain scheduling control for spacecraft rendezvous system with actuator saturation.The main content of this dissertation includes the following aspects:Chapter 1 includes the research background and significance of the topic,the current development of the spacecraft elliptical orbit rendezvous system with constraint control and gain scheduling control approaches,as well as the main innovation points of this dissertation.Chapter 2 establishes the spacecraft elliptical orbit rendezvous system with actuator saturation and gives the preliminary knowledge required in this dissertation.Chapter 3 investigates the design problem of discrete gain scheduling state feedback control for spacecraft elliptical orbit rendezvous system with actuator saturation.Due to the presence of actuator saturation,the dynamic performance of the spacecraft elliptical orbit rendezvous system with actuator saturation degrades significantly.In order to improve the dynamic performance of the spacecraft elliptical orbit rendezvous system with actuator saturation,Lyapunov function method and rotation(reflection)transformation technique are adopted to construct a group of time-invariant ellipsoidal invariant sets,which can be used to determine the switching points of the discrete gain scheduling control.By appropriately choosing some discrete parameter values,the discrete gain scheduling control is obtained from a solution of a periodic Riccati matrix differential equation.Under the control obtained,the dynamic performance of the spacecraft elliptical orbit rendezvous system with actuator saturation is much improved while accomplishing successfully the rendezvous mission of the spacecraft.Finally,numerical simulation is given to show the effectiveness of the proposed control design approach.Chapter 4 investigates the design problem of discrete gain scheduling output feedback control for spacecraft elliptical orbit rendezvous system with actuator saturation.Due to environmental factors or limitations of technical equipment,the state of the control system is not easy to measure in practical problems.Therefore,in many cases,it is impossible to directly obtain all the state variables of the system,making it difficult to achieve state feedback control.Thus,based on invariant set theory and periodic Riccati matrix differential equation,a discrete gain scheduling output feedback control based on state observer is designed.Under the control obtained,the dynamic performance of the spacecraft elliptical orbit rendezvous system with actuator saturation is much improved while accomplishing successfully the rendezvous mission of the spacecraft.Finally,numerical simulation is given to show the effectiveness of the proposed control design approach.Chapter 5 summarizes the main work of this dissertation and puts forward further research ideas.