【作者】 贺从园；

【导师】 张卯瑞；

【作者基本信息】 哈尔滨工业大学 ， 导航、制导与控制， 2011， 硕士

【摘要】 本文以X-33飞行器为研究对象,首先根据飞行器再入过程的特点,在半速度坐标系中建立了三维再入运动方程,确定以高度、经度和纬度在终点时刻的误差平方和为最小的目标函数,详细分析了再入过程中所需要满足的过载、动压及热流率约束条件,设计了以高度-速度为剖面的再入走廊。论文详细介绍了高斯伪谱法(GPM)的基本原理及特点,并且基于高斯伪谱法将研究的最优控制问题成功转化成非线性规划问题,通过实例仿真分析了该优化算法的收敛速度、精度以及实时性。在采用高斯伪谱法(GPM)进行飞行器轨迹优化设计时,结合仿真数据得出了不同情况下的航向角,航迹角、经度及纬度等状态变量的变化曲线,以及在终端时刻的落点误差数据,通过仿真分析了初值估计、配置点个数等因素对轨迹优化的影响。本文通过仿真分析了存在初始误差和气动系数误差情况下的落点误差,结合仿真数据得出了两种情况下的实际轨迹曲线与参考轨迹曲线,最终采用线性二次型调节器(LQR)对参考轨迹进行跟踪,并通过仿真分析了其鲁棒性。更多还原

【Abstract】 In this paper, it chooses the X-33 aircraft as the research object. Firstly, according to the characteristics of the reentry process, it creates the reentry equations of motion in the half-speed coordinate system. It gives the objective function that makes the errors of the height, longitude and latitude minimum at the end of time. Meanwhile it analyses the constraints of the overload, dynamic pressure and heating rate. Finally it establishes the reentry corridor of the height-speed profile.This paper introduces the basic principles of the Gaussian pseudo-spectral method (GPM) and transforms the optimal control problems into solving the parametric problem of state variables and control variables. Ultimately it analyses the convergence speed and accuracy of the Gaussian pseudo-spectral method (GPM) when solving optimal control problems.During the design of aircraft trajectory optimization, it draws the curves of the flight path angle, longitude, latitude and other state variables and gives the errors at the terminal time through the simulation analysis. Meanwhile it analyses the effects of the initial estimates of the value, the number of collocation points on the trajectory optimization.This paper analyzes the errors at the end point in the presence of aerodynamic coefficients errors and initial errors through the simulation analysis. At the same time it gives the curves of the actual trajectory and the reference trajectory. Ultimately it uses the linear quadratic regulator (LQR) to track the reference trajectory and analyses its robust characteristics.更多还原