Precision Landing Trajectory Planning And Guidance For The First-stage Of Launch Rocket

Reusable first-stage rocket can dramatically reduce the launch cost,shorten launch period,and avoid the damage to ground residents.Therefore,it has a broad trend.For the reusable first-stage rocket,the rapid trajectory planning and high-precision guidance are required.In this dissertation,we study the trajectory planning and guidance methods for the recovery of the first-stage rocket.The main contributions are listed below:To design standard recovery trajectory,a hybrid trajectory optimization method based on penalty function,genetic algorithm and sequence quadratic programming(SQP)method is proposed.In this method,the trajectory planning problem is firstly optimized by genetic algorithm to obtain a lower precision solution.Based on this solution,the problem is optimized again by SQP algorithm to obtain a higher precision solution.The simulation results show that the hybrid optimization algorithm can obtain a higher precision trajectory.The reentry trajectory tracking guidance method is studied.Firstly,the reentry perturbation equations with height as the independent variable is established.Then,a disturbance observed-based dynamic inversion tracking guidance method is proposed.The simulation results show that the proposed guidance method has high guidance precision and strong robustness.For the landing trajectory planning problem,a convex optimization method is proposed.Firstly,the model of trajectory planning for landing section is established.Secondly,the problem is transformed into a convex approximation problem by using lossless convex optimization and linearization.Finally,the successive convex optimization algorithm is used to solve the problem approximation iteratively to obtain the optimal solution of the original problem.Simulation results show that the proposed method can quickly obtain the optimal trajectory.The guidance method based on trajectory online planning is studied.Firstly,a switch-on strategy is proposed to ensure that the trajectory planning problem at the start point of landing phase is feasible.Secondly,for closed-loop online trajectory planning,a thrust regulation strategy is designed.Finally,in order to improve the anti-interference capability,a trajectory tracking guidance method based on apparent acceleration compensator is proposed.The simulation results show that the proposed method has strong robustness and high guidance precision.This study can provide a theoretical basis for the development of trajectory planning and guidance technology of reusable launch vehicle and provide technical support for the development of reusable launch rocket in China in the future.