Abstract:In view of the complex dynamics of spaceborne antennas, the pointing control method of spaceborne moving parts is studied from the rigid-flexible coupled dynamics modeling, tracking control and vibration suppression of antenna systems. Firstly, to simplify the dynamics modeling, the system kinematics equations are established by geometry topology; then, modeling the mode of vibration of the antenna reflector by the hypothetical modal method; finally, the multi-body dynamic model is combined with the flexible joint model, thereby the nonlinear rigid-flexible coupled dynamics model of the spaceborne antenna is established. Based on the above complex dynamic modeling, the control strategy is designed by adopting the idea of layered design. Firstly, the coupling control law of the spaceborne antenna system without considering flexible joints is obtained by using the sliding mode controller based on the calculated torque method, thus the stability of the satellite base and the vibration suppression of the flexible reflector of the antenna is guaranteed. Then the backstepping method is used to control the flexible joint to guarantee the precision of pointing control of the antenna reflector. Finally, the influence of uncertainty of dynamic parameters on system tracking and pointing control is discussed, and the dynamic model and control algorithm are verified by mathematical simulation. The simulation results show that this method can preferably achieve the tracking control and vibration suppression requirements and improve the dynamic pointing accuracy of the spaceborne antenna.