Robust Adaptive Control Algorithms Research For The System Of Spacecraft Attitude Dynamics

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. In the meanwhile, an introduction of the Lyapunov-based stability theory and sliding mode variable structure control as the theoretical basis of the designed control algorithm is given. This dissertation designs corresponding control schemes to solve several practical problems that do exist in satellite attitude control by using Lyapunov-based stability theory.To solve the problem of the uncertainty of inertia moment and the disturbance torque, attitude regulation and tracking algorithms are designed. Sliding mode variable-structure control is the effective way to handle nonlinear control, which is robust to bounded disturbance and variation of moment parameters. And then through the mathematical simulation of attitude adjustment and tracking algorithm was verified, this chapter of the sliding mode adaptive controller is robustness to bounded disturbance and variation of moment parameters, the results show that the designed control algorithms guarantee the closed-loop system to achieve global stability, and achieve good posture for attitude adjustment and tracking tasks.To solve the problem of control saturation, attitude regulation and tracking algorithms are designed. By utilizing the property of hyperbolic tangent saturation function and MRP, the attitude regulation and tracking control algorithms are designed, which can guarantee the control constraints of closed-loop when control parameters design meet specified conditions. And then through the mathematical simulation of attitude adjustment and tracking algorithm was verified, this chapter of the sliding mode adaptive controller is robustness to bounded disturbance and variation of moment parameters, the results show that the designed control algorithms guarantee the closed-loop system to achieve control saturation and global stability, and achieve good posture for attitude adjustment and tracking tasks.Numerical simulations for proposed control algorithms are performed. The results show that all the control schemes commendably achieve the attitude control missions.