Reentry Trajectory Rapid Planning Algorithm Based on Energy Allocation Optimization

Abstract

In order to improve the adaptability of lift reentry vehicle (LRV) when facing unknown disturbance and interception during reentry, an algorithm based on energy allocation optimization for trajectory planning was designed. First, The reentry phase was divided into three sub-phases: initial descend phase(IDP),energy optimal phase(EOP) and energy manage phase(EMP) . A flight mode was proposed in which LRV flies in the most energy saving way during EOP, and the remaining energy is consumed in EMP. The analytical expression of the shortest trajectory length required by EMP under the equilibrium glide condition was derived. Then,the IDP and EOP program algorithms were designed,and the analytical solution of EMP range was derived,based on which an iterative algorithm was developed for the smooth transition between EOP and EMP. Integrating with bank angle flip technique, an EMP programming algorithm was designed,in which two bank angle reversals were programmed to eliminate the lateral range error and heading angle error. Finally, a rapid planning algorithm for energy allocation optimized trajectory (EAOT) was constructed and verified by simulation. According to the simulation result,the proposed EAOT can increase the energy margin for LRV confronted with disturbance and interception,and the designed planning algorithm can complete trajectory planning rapidly,possessing an appealing application value in engineering.