基于直接配点法的滑翔轨迹快速优化设计

介绍了基于五次Gauss-Lobatto多项式的直接配点法在再入飞行器三维轨迹最优化问题中的应用。首先给出了再入飞行器轨迹优化问题模型，其中运动方程为三自由度模型，性能指标选为到达指定地点飞行时间最短，控制变量则为无量纲升力系数和倾侧角。再入飞行过程中受到加热率、过载和动压约束，终端状态受到目标位置约束。然后，应用直接配点法将最优控制问题离散化为非线性规划问题，将动态优化问题转化为静态参数最优化问题。选取各节点和配点上的状态量和控制量作为优化参数。最后应用SNOPT软件包对参数最优化问题进行求解。仿真结果表明直接配点法对于再入飞行器轨迹初始参数取值不敏感，且求解过程具有一定的实时性。

Reentry Trajectory Optimization for Hypersonic Glide Vehicle

Direct method based on Fifth- degree Gauss- Lobatto polynomial was introduced to optimize reentry trajectory. The model of reentry vehicle＇s trajectory optimization was introduced, and the performance index was minimizing the flying time from initial location to target. The control variables are non- dimensional lift coefficient and bank angle. The trajectory was constrained by heating rate, overload and dynamic pressure. The terminal state was confined by object location. The optimal control problem was discrete into nonlinear programming problem and the dynamic optimize problem was translate to a static optimize problem. The state parameter and control parameter at discrete point was optimized using SONPT software package. The result shows that the direct collocation method is insensitive to the initial guess and fairly good in real- time.