再入轨迹跟踪控制的非线性方法研究

Research on New Nonlinear Control Method Applied in Tracking Control Problem

针对高度变化大,速度变化快的可重复使用飞行器的再入轨迹跟踪问题,选用名为状态相关Riccati方程的一种新型非线性控制方法进行再入轨迹跟踪控制器设计。同时在几乎所有涉及Riccati方程的控制器设计问题中,合适的加权矩阵的选择通常是比较棘手的。针对这个问题,提出了一种有效的权阵选择方法,避免了试凑等传统方法带来的误差和工作量。随后给出了最优再入轨迹跟踪控制器的详细设计过程,并在一定的气动摄动条件下进行飞行仿真。仿真结果表明了这种方案的可行性,实用性和鲁棒性。

Re-entry tracking control of Reusable Launch vehicle is a very challenging task since the vehicle dynamics changes dramatically. Sate-Dependent Riccati Equation （SDRE） method which is characterized by state-depended controller was applied here to track optimal entry trajectory. Meanwhile, in order to solve the weight matrix selecting problem which is a difficult problem in Riccati-controller＇s design, a new parameter-selecting method was introduced. Detail procedure of a longitudinal entry tracking control law based on SDRE was proposed, from which it can be seen that SDRE method is very easy to implement whether on the mathematical deduction or the online calculation. Numerical simulation for SDRE tracking law was carried out, and compared to traditional tracking method to demonstrate the simplicity, robustness, and doable performance of SDRE controller.