A Cluster-Like Rigid-Flexible Spacecraft Model And Inverse System-Based Attitude Control

As a consequence of the increasing demand for high performance positioning and rapid maneuvering in space missions, research works have focused considerable attention on the modeling and control of the rigid-flexible coupling spacecraft in last twenty years. Especially, the spacecraft whose configuration is composed of the central rigid body and some fixed or hinged flexible appendages is excessively paid attention to. Therefore,the dissertation is based on the pre-research defense project"Research of the intelligent adaptive inverse control for flexible satellite"of the National 10th five-year plan and the National Natural Science Foundation of China"Research and application of intelligent adaptive inverse control for a class of complex system". Dynamic model, kinetic model and beam vibration model of a cluster-like rigid-flexible spacecraft are given and analyzed. Inverse system method is studied in detail, and inverse system's analytic construction is presented. Inverse system method and internal mode principle are used to attitude control design for a spacecraft with actuators and without actuators, and simulations are done. Research contents are followed:Firstly, attitude dynamic model of a cluster-like rigid-flexible spacecraft and Euler-Bernoulli beam vibration model are established. Newton-Euler method is used to derivate attitude dynamic model, and kinetic mode is described in the form of Euler angle. Tiny element method is used to derivate vibration model, and vibration equations are solved by using fixed-free standard modes. The influence that spacecraft's maneuvers impose on the flexible beam and its counterpart are analyzed based on kinematic equations, dynamic equations and vibration equations. Numerical calculation of environment moments is done.Secondly, Inverse system method is studied from two ways-state equations and differential equations. Improvement of Interactor algorithm is presented in order to construct analytic inverse system. Construction of generalized inverse system is discussed in detail. Stabilization and non-idealization for pseudo-linear system are analyzed, and pole assignment and internal model principle are applied to the closed-loop system. Robustness of the multiplex controller which is composed of inverse system and internal model controller is proved. Inverse system method is applied to spacecraft attitude control. Performance difference between pole assignment and internal control which acts as the closed-loop controller is compared. Simulation result shows that the latter has strong robustness in spacecraft attitude control, and added pre-filter reduce control value.Inverse system method is also applied to attitude control of the spacecraft with flywheels. A MIMO dynamic simulation model is established via the machine- electricity equations, Dahl friction model and air resistance model, and effect that friction has on the flywheel is evaluated. It is presented that voltage compensator, which is based on a state observer, is designed at low speed and high speed. Spacecraft attitude controller integrates inverse system and internal controller. Simulation result shows the attitude controller is feasible. Because a hysteresis essential nonlinearity is a part of the spacecraft with PWPF modulation, inverse system method can't be used. Lyapunov function-based control law is presented, and its stability is analyzed. Simulation result shows the attitude controller is validate.Finally, the inverse system method is applied to the attitude control of the flexible spacecraft. Inverse system of the plant is individually obtained by using Analytic construction and neural network construction. Internal controller is used as the closed-loop controller. Simulation result shows the attitude controller is validate.