高超声速飞行器多约束再入轨迹快速优化

针对高超声速飞行器再入过程中面临测控区和绕飞区的再入轨迹设计问题，提出了一种基于Gauss伪谱法(GPM)的分段轨迹优化策略。将轨迹优化的一般最优控制问题转换为多段最优控制问题，进而将各段轨迹按Gauss伪谱方法进行离散化，将连续多段最优控制问题转换为非线性规划问题(NLP)进行求解。所得再入轨迹能够使得飞行器在满足各种约束条件的情况下成功进入测控区并且有效规避绕飞区，最终到达指定点。此外，本文综合考虑飞行器再入飞行的快速性和工程实用性，并提出了再入时间、弹道倾角以及航向角相关指标的加权性能指标，同时保证了轨迹规划快速、再入轨迹平滑以及控制量变化平缓等实际需求，提高了计算效率。仿真结果表明，本文所提出的分段优化方案能够快速规划出适应不同飞行任务的再入轨迹。

Fast Optimization of Reentry Trajectory for Hypersonic Vehicles with Multiple Constraints

A segmented trajectory optimization strategy based on the Gauss pseudospectral method (GPM) is proposed for hypersonic vehicles during reentry where some monitoring and no-fly zones are inevitably encountered. The segmentation of the trajectory converts the original optimal control problem of the trajectory optimization into the multi-segment optimal control problem. With the help of GPM, each segment trajectory is planned according to the standard computing procedure of GPM. The whole trajectory thus obtained can make the vehicle smoothly enter into the monitoring zones, successfully circumvent the no-fly areas, and finally reach the predetermined point. Besides, considering the requirements of the high computing efficiency and the engineering practicability, we put forward a weighted performance index of reentry time and path-and-heading-angle related variables. The proposed performance index and corresponding optimization strategies definitely provide us the rapidity of the path planning, the smoothness of the flight trajectory, the flatness of the controlled variables, and the improvement of the computational efficiency. The simulation results show that the piecewise optimization scheme proposed in this paper can quickly plan a reentry trajectory for a hypersonic vehicle with complex constraints.