Research On Trajectory Optimization And Guidance Approach For Hypersonic Gliding Vehicle

Hypersonic gliding vehicles have been drawing a lot of attention in recent decades,and will be the most suitable weapon to conduct prompt global strike and preserve distinctive air superiority in the future.In order to improve the survivability and fighting strength of hypersonic gliding vehicles,it is significant to design optimal trajectory optimization methods and guidance methods in the re-entry phase.This paper takes a hypersonic gliding vehicle(CAV-H)as the object of study and focuses the multiobjectives flight trajectory optimization,the online flight trajectory optimization and trajectory tracking guidance.The main results obtained in the dissertation are as follows:First of all,the problem of multi-objective re-entry trajectory optimization is usually solved by the weighted summary method(WSM).However,it is difficult to obtain the non-convex Pareto non-inferior solution.To overcome this problem,the trajectory optimization is established with the physical programming(PP)method,which is capable to obtain solution with less computational intensity and reflect the designer's preference.The numerical simulation considers four objectives: maximum terminal velocity,maximum range,minimum peak value of heating rate,and minimum oscillation.Performance of PP-based re-entry trajectory optimization is demonstrated in 3-D nonlinear dynamics scenario.The numerical simulation results show that it can easily realize and improve the performance of the hypersonic gliding vehicle.Secondly,in order to meet the robustness and real-time requirements of the online trajectory optimization,a new trajectory based on the hybrid surrogate model is proposed.The EI method and EG method are used to the hybrid surrogate model respectively.The simulation results are compared with the single surrogate model optimization results.And the results show that the hybrid surrogate model optimization can obtain the ideal trajectory quickly.And faced with the disturbance of initial state,the speed of calculation is very fast and accurate.The research has certain engineering application value.Last but not least,due to the poor surrounding adaptive ability of the traditional guidance methods,a novel methodology combining nonlinear model predictive control and approximate dynamic programming,named as model predictive static programming(MPSP),is used to solve a class of finite-horizon optimal control problems with hard terminal constraints.The main feature of this guidance law is that it is capable of hitting the target with high accuracy for vehicles.Performance of the MPSP-based guidance is demonstrated in the consideration of planet uncertainties and external disturbances.The numerical simulation results show that the proposed guidance methodology has the advantage of computational efficiency and better robustness against the perturbations.In this paper,trajectory optimization and guidance method for hypersonic gliding vehicles in the reentry process are preliminarily studied.The results of the dissertation can be used as reference for other study.