基于非线性动态逆的SRLV再入段控制律设计

Nonlinear Dynamic-Inversion Reentry Flight Control of Suborbital Reusable Launch Vehicle

基于非线性动态逆理论,设计了亚轨道可重复使用运载器(SRLV)的再入控制律。首先,分析了SRLV再入段的数学模型,并给出了反作用推力控制系统(RCS)的控制模型;其次,将非线性动态逆方法与时标分离原则相结合,考虑飞行器姿态控制系统的外环角回路的慢变特性和内环角速度回路的快变特性,独立设计了两个回路的控制律;最后,为了增强系统的鲁棒性,分别在两个回路中引入了比例-积分反馈,有效地抑制了干扰力、力矩和非线性对消带来的逆误差。仿真结果表明,设计的控制律对SRLV再入段具有很好的控制效果。

The objective of this paper is to design the reentry flight control laws for the Suborbital Reusable Launch Vehicle （SRLV） based on nonlinear dynamic-inversion. Firstly, the control of reentry phase and the model of RCS jets are presented. Then the flight control system is divided into two subsystems based on the time-scale separation principle. The fast states subsystem corresponds to the three body-axis angular rates, the slow states sub- system controls the angle-of-attack, sideslip angle and the rate of the bank angle about the velocity vector. Lastly, the proportional-plus-integral feedback is designed to increase the system robustness. Finally, the simulation proves that this, method is effective for the SRLV.