针对多变量、不稳定的近空间飞行器姿态系统,在系统存在参数不确定和外部干扰的情况下,并考虑执行器动态和输入受限,提出一种鲁棒可重构跟踪控制策略.首先,利用二阶滑模干扰观测器分别重构姿态、角速率回路的复合干扰;其次,采用鲁棒二阶滑模积分滤波器的反推(backstepping)方法避免了控制器设计中微分项膨胀问题,利用鲁棒项抵消重构误差对系统的影响,以实现姿态控制器设计.然后,在考虑执行器动态、输入受限及舵面卡死故障下,给出一种线性矩阵不等式的在线优化舵面分配算法,以实现飞行器的姿态角渐近跟踪期望的制导指令.最后,仿真结果表明所提出的方法具有良好的跟踪控制性能.
We propose a robust reconfigurable tracking control scheme for the multi-variable and unstable attitude system of the near-space vehicle (NSV) with parameter uncertainties, external disturbances, dynamic actuator and input constraints. A second-order sliding-mode disturbance observer is used to reconstruct compound disturbances in the loops of attitude and angular rate respectively. The backstepping method with integral filter is used to avoid the growing of differential orders in controller design. The robust terms offset the impact of the reconstruction errors on system performances. By considering actuator dynamics, input constraints and jammed faults, we propose an online linear-matrix-inequality (LMI) optimization distribution algorithm for tracking desired guidance commands. Simulation results show good tracking control performances of the proposed method.