An Approach For Reusable Booster Vehicle Robust Attitude Control Based On Disturbance Rejection

Reusable Booster Vehicle is a feasible project to reduce the cost of space transportation and improve the efficiency of space launch system at present. It could be able to complete a variety of space transportation task with different kinds of upper stages and lay the foundation for the realization of fully reusable space launch vehicle system. Reusable Booster Vehicle adopts Bank-to-Turn maneuvering, which leads to strong coupling and nonlinear dynamics with fast time-varying parameters and much uncertainty and disturbance, making attitude control system design an essential topic. To this end, this dissertation focuses on the approach for robust attitude control system design. The main contents and results of this research are as follows:The kinematic and dynamic equations of the position and attitude motion of Reusable Booster Vehicle are established. According to the flight characteristics, taking angle of attack, sideslip angle and roll angle as control variables, the equation model of Bank-to-Turn attitude motion in three channels with coupling is derived in detail with simplification and assumptions.A control design method based on equivalent-input-disturbance and generalized extended state observer is proposed. The method regards the uncertainty and disturbance as a lumped disturbance applied in the input channel, decoupling and linearizing the model in three channels. The uncertainty and disturbance is compensated through the estimation of generalized extended state observer and linear state feedback. Meanwhile, closed-loop stability of the method is also proved. There is no need for system transformation, exact plant model or any information about uncertainty and disturbance, and only single measured output is necessary in the method, which extremely reduces the complexity of control system design. A Reusable Booster Vehicle engineering example is taken as the object. The method is applied to the control system design for angle of attack, sideslip angle and roll angle tracking control. The feasibility of the method is illustrated by the satisfactory performance through the simulation.The application of gain scheduling PID control and sliding mode dynamic inverse control to control system design of the Reusable Booster Vehicle engineering example is conducted. The time is adopted as the scheduling variable in gain scheduling, and the optimization and design of the PID controller is carried through genetic algorithm and engineering principles. Single dynamic inverse structure and high gain sliding mode with saturation function is used in sliding mode dynamic inverse control application. Comparison of the three controllers is implemented through normal and bias simulation in different cases of significant uncertainty and disturbance. Both gain scheduling PID controller and sliding mode dynamic inverse controller fails under certain uncertainty and disturbance, while the results of the proposed controller show excellent performance with high accuracy, fast response and nearly no time-delay. The effect of the considerable uncertainty and disturbance is successfully attenuated and rejected, where the effectiveness and the robustness of the proposed method is demonstrated and validated.To conclude, this dissertation has a systematic approach on the issue of Reusable Booster Vehicle robust attitude control system design. This research could offer theoretical support and provide engineering realization for high accuracy flight control system design, and is also an essential reference and a meaningful study topic to robust control system design and disturbance rejection methodology.