Attitude Control Algorithms Research For Three-Axis Stabilized Satellite

Satellite attitude control system is the important part of the satellite system, the accuracy of attitude control system depends not only on the performance of the hardware of the measurement, but also on the attitude control algorithm. In this dissertation, the attitude control algorithms are deeply studied theoretically and practically for the attitude control of the three-axis stabilized satellite. The main contents of this dissertation consist of the following parts:The mathematical model is founded. All the control schemes are designed on the basis of the dynamic equation and kinematic equation given in Chapter 2, and Modified Rodrigues Parameter (MRP) is adopted to describe satellite attitude in view of its combination with its Shadow Set can implement global nonsingular representation. This dissertation designs corresponding control algorithms to solve several practical problems that do exist in satellite attitude control by using Lyapunov-based nonlinear control methods.To solve the problem of control saturation, in the case of knowing the attitude and angular velocities of satellite, a full state feedback algorithm which performs attitude regulation and tracking is designed. First, attitude algorithms are designed under limited disturbance, which can guarantee the global asymptotic stability and control constraints of closed-loop when control parameters design meet specified conditions. And the scheme is model-independent which does not rely on the inertia moment of the satellite. Linear saturation function is introduced into attitude regulation and tracking control algorithm, in which both control constraints and angular velocity constraints are considered. At last, by utilizing the property of hyperbolic tangent saturation function and MRP, the attitude regulation and tracking control algorithms are designed. To solve the tracking problem, considering the uncertainty of inertial moment parameters, both non-adaptive and adaptive control schemes are designed separately. And an optimized control scheme based on genetic algorithms (GAs) is addressed.Aiming at the output feedback control problem and assuming the attitude can be measured, the algorithms of attitude regulation and tracking are designed by constructing dynamic filter to perform the output feedback control needless angular velocity signal, which is to adopt attitude described by MRP and state-feedback of filter to perform the output feedback control. Because of having adopted hyperbolic tangent saturation function and general saturation function, partial output-feedback scheme can handle the problems of limited control torques. Each algorithm, analyzed by Lyapunov stability theory, can guarantee global asymptotic stability of closed-loop system, and can implement the attitude regulation and tracking task.To solve the problem of the uncertainty of inertia moment and the disturbance torque, attitude regulation and tracking algorithms are designed. Considering the advantages of sliding mode variable-structure control, a sliding mode adaptive regulation and tracking algorithms are proposed, which can perform effective attenuation of bounded disturbance and implement real-time identification of inertia moment. And sliding mode PID attitude regulation and tracking algorithms are proposed, theoretical analysis proves the robustness to bounded disturbance and variation of moment parameters. Finally adaptive attitude regulation and tracking algorithms are proposed, which guarantee the closed-loop system is ISS to bounded disturbance, and control parameters are dynamic adjusted, and adaptive control algorithms implement identification of inertia moment.Based on some practical satellite, numerical simulations for proposed control algorithms are performed. The results show that all the control schemes commendably achieve the attitude control missions. Finally semi-physical simulations badsed on dspace real-time simulation system for some proposed control algorithms are performed using existing hardware. Therefore, the results of the thesis, apart of theoretical interest, can provide a good design example for practical engineers as well.