Research On Attitude Control And Under-actuated Control Of Aerospace Vehicles

The current research in developing next generation reusable flying vehicles is focused on aerospace vehicles (ASVs). It is significant to control the aerospace vehicle's attitude system. The control system of the ASV's attitude several challenges due to the nonlinear, strongly coupled and uncertain model with uncertain disturbance and complicated conditions. In this dissertation, three relative problems, i.e. modeling of a conceptual ASV, attitude system controller design and under-actuated control system design, are studied.Firstly, based on the mechanics analysis of the ASV, establish simulation model of the ASV, which includes the whole of kinetic equations and motion equations. And write in a specific form of three-channel. It lay the foundation for the followed design.Secondly, based on the nonlinear, strongly coupled and uncertain model of the aerospace vehicle's attitude system, a global terminal sliding mode control method is proposed. Based on the feedback-linearization technique, the system is firstly decoupled into three independent SISO subsystems, and then controllers for each subsystem is designed. At last, method is proved to be correct by the Matlab. And prove the anti-interference ability of the method, with unknown disturbance condition.Finally, based on rigid spacecrafts with two flywheels, study the problems of attitude control. A new controller is designed by using the Backstepping sliding mode control method for the under-actuated systems described by (w,z) parameter, under the assumption of zero momentum for the spacecraft. And simulation results indicate the feasibility and robustness of the method presented above.