复杂动力学模型下星载天线跟瞄控制技术研究

针对星载天线动力学复杂这一问题，从天线系统刚柔耦合动力学建模、指向跟踪控制以及振动抑制等方面研究了柔性星载运动部件的指向控制方法。首先，通过描述系统几何拓扑关系建立系统运动学方程，从而简化动力学建模过程；之后，利用假设模态法，对天线反射面挠性进行建模；最后，将拉格朗日方程与挠性关节模型相结合，从而建立了星载天线非线性刚柔耦合动力学模型。在以上复杂动力学建模的基础上，采用分层设计的思路进行了控制策略设计：先运用基于计算力矩法的滑模控制器得到不考虑挠性关节的耦合控制律，从而保证卫星基体的稳定性以及天线挠性反射面的振动抑制；再使用反步法对挠性关节进行控制，实现对天线反射面的指向精度控制。最后，讨论了动力学参数不确定性对系统跟踪指向控制的影响并采用数学仿真的方式验证了相关动力学模型与控制算法。仿真结果表明该方法能较好地实现对星载天线的指向跟踪控制以及振动抑制，提高星载天线的动态指向精度。

Tracking and Pointing Control of Spaceborne Antenna under Complex Dynamic Model

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.