附着小天体的动态面鲁棒制导与控制方法

以精确附着小天体表面的任务为背景,提出一种基于扰动观测器(DOB)和动态面控制的附着小天体的制导与控制方法。根据探测器的初始条件与终端着陆条件规划了标称轨迹,并将引力场建模误差、参数摄动和外部干扰等视为总扰动,结合动态面控制和DOB设计了标称轨迹跟踪控制器。分析总扰动估计误差的渐进收敛性以及闭环标称轨迹跟踪控制系统的稳定性,并确定控制器参数选取条件。数值仿真结果表明,所设计的DOB可以有效地估计并抑制总扰动且闭环标称轨迹跟踪控制系统具有良好的稳定性和控制精度。

Dynamic Surface Robust Guidance and Control for Landing on Asteroids

With a comprehensive application of the theory of the disturbance observer based (DOB) control and dynamic surface control, this paper develops a dynamic surface robust guidance method for precise landing on asteroids. A reference trajectory is first generated by using the spacecraft initial conditions and the terminal landing constraints. We consider the gravitational field modeling errors of the asteroid, parameter perturbations of the spacecraft, and external disturbances as a lumped disturbance of the dynamic system and then design a reference trajectory tracking controller using the DOB technique and dynamic surface control theory. We analyze the asymptotic convergence problem of the estimation of the lumped disturbance. We also present the stability analysis of the closed-loop reference trajectory tracking control system and develop a method to determine the controller parameters. Numerical simulation results show that the DOB designed in this paper can estimate the lumped disturbance effectively and that the closed-loop reference trajectory tracking control system has a fine stability and control precision.