基于非线性干扰观测器的临近空间拦截弹姿态控制

Attitude control of near space interceptor based on nonlinear disturbance observer

为满足临近空间拦截弹在大干扰强耦合情况下高精度姿态控制问题,设计了基于非线性干扰观测器的自适应鲁棒反演控制器。建立了基于直接力控制的拦截弹三通道姿态控制系统模型;采用二阶滑模微分器,估计计算反演控制中虚拟控制量的导数,解决了"微分膨胀"的问题;为提高姿控系统控制精度,对模型的未知信息和外界干扰做高精度的估计和补偿,依据二阶跟踪微分器,设计了一种新型非线性干扰观测器;并采用PSR调制器将连续控制量离散化,通过姿控发动机实现变推力控制。数字仿真结果显示,设计的姿态控制器跟踪速度快、精度高,对系统不确定和干扰具有强鲁棒性。

In order to meet the high-precision attitude control problem of adjacent space interceptor in the case of large disturbance and strong coupling,an adaptive robust inversion controller based on nonlinear disturbance observer is designed.A three-channel attitude control system model based on direct force control has been established.The second-order sliding mode differentiator is used to estimate the derivative of the virtual control quantity in the inversion control,which solves the problem of"differential expansion".In order to improve the accuracy of attitude control system,high-precision estimation and compensation of unknown information and external disturbance of the model,a new nonlinear disturbance observer is designed according to the second-order tracking differentiator.The continuous control amount is discretized by PSR modulator.The attitude control engine achieves variable thrust control.The digital simulation results show that the designed attitude controller has fast tracking speed,high precision and strong robustness to system uncertainty and interference.