基于实时控制分配策略的航天器姿态跟踪

Spacecraft Attitude Tracking Based on Real Time Control Allocation Strategy

针对含有冗余执行器的航天器姿态跟踪控制系统,首先将故障观测器得到的执行器部分失效因子估计矩阵的逆作为权值矩阵,改进了开环伪逆控制技术,并进一步考虑执行器饱和以及响应速率约束,设计了基于向量二次最优规划的开环动态控制分配方案。考虑到执行器安装矩阵偏差会导致开环实时控制分配策略方案产生的执行器实际力矩与控制器期望力矩误差,设计了实时控制分配策略的系统结构,并给出了实时控制分配策略系统稳定的一个充分条件。最后,通过MATLAB仿真实验,从结果中看出在保证实时控制分配策略系统角速度误差和姿态四元数误差快速收敛的同时,各执行器的输出力矩均能满足输入饱和受限及响应速率约束,验证了本文设计的实时控制分配策略方案的有效性和可靠性。

As for spacecraft attitude tracking system with redundant actuators,this paper improves the traditional pseudo-inverse control allocation by using the inverse matrix of actuator partial loss effectiveness estimation matrix as weigh matrix. Taken further actuator saturation and output velocity constrains into consideration,this paper proposes an open loop dynamic control allocation based on vector quadratic optimal planning. The deviation of actuator installation matrix may result in error between actual moments generated by open loop control allocation with expected moments provided by the virtual controller. This paper proposes a closed loop control allocation,and provides a sufficient condition of stability. Finally,with MATLAB simulation,it can be found from the experiments results that the angular velocity error and attitude quaternion error of closed loop control allocation system will achieve convergence in a rapid speed.Meanwhile,the output torque of every actuator could satisfy the input saturation and the response rate constraints. Thus,the effectiveness and reliability of closed loop control allocation strategy are demonstrated.