基于滚动优化和微分Theta-D方法的快速绕飞航天器姿轨协同控制

针对近距离快速绕飞的视线保持要求和姿轨耦合特点,研究航天器姿轨协同最优控制方法。建立了六自由度相对运动耦合非线性模型,偏心推力矢量同时提供位置和姿态控制能力;考虑到近距离相对运动对动态性能的高精度要求,不同于无限时域经典Theta-D方法,提出了一种包含终端状态约束的滚动优化有限时域最优控制快速解算方法,推导了中间过程微分Riccati方程和微分Lyapunov方程的横截条件。控制器设计充分考虑了有限脉冲小推力器和有限力矩输出装置的约束。对近距离快速绕飞的仿真结果说明了方法的有效性,所提方法在保证相对运动稳定和动态性能的前提下控制输出幅值小,具有工程实际意义。

Cooperative Relative Attitude and Translation Control Based on Finite Horizon Optimization and Differential Theta-D Method

Driven by the close proximity fast fly-around features such as light of sight(LOS) holding requirement and coupled translation and attitude control,a cooperative translation and attitude optimal control method for spacecraft is studied.The coupled nonlinear equation of 6 DOF relative motion is obtained,and eccentric thrust vector is used to provide position control forces as well as attitude control torques.Considering high accuracy dynamic performance demand for close proximity relative motion,a finite horizon optimal control computing method including final state constraints different from the classic infinite horizon Theta-D method is proposed.Differential Ricatti equation and differential Lyapunov equation in process are also prescribed.Constraints of small finite impulse thrusters and finite torque transformation equipments are completely embedded in controller design.Simulation results of close proximity fast fly-around show that the proposed method can get small control output under the condition of guaranteeing stability and performance requirement of relative motion,and have some engineering sense for potential application.