Trajectory Of Re-entry Planning Of Hypersonic Vehicle In Near Space And Flight Performance Computation

The purpose of this paper is to plan the trajectory of its non-powered glide re-entry,a near-space vehicle based on a space-based platform.At the same time,some work on the flight performance calculation of the aircraft was also carried out.This provides effective reference data for the conceptual design of near space vehicles.In the aspect of flight performance calculation,this paper refers to the empirical formula and engineering algorithm of related performance calculation in the military aircraft design manual,and compiles an assistant tool for flight performance calculation of aircraft.In the aspect of reentry trajectory planning design,firstly,the re-entry kinetic equation and kinematics equation of the aircraft under the complex environment model are established in this conditions were compared,and the initial re-entry conditions are determined by analyzing the results,.The parameters to be optimized in the planning and design are also determined as flight angle of attack.Then the traditional optimization method is analyzed,and it is found that the traditional single objective optimization trajectory will lose other performance greatly in exchange for the optimization of the objective function.This paper adopts the design idea of the nominal angle of attack,which is usually used in the aviation return engineering.The glide re-entry trajectory is divided into three separate sections.At the stage of initial subduction,we need to control the effect of heat flow rate In the second section,particle swarm optimization algorithm based on simulated annealing algorithm optimizes the angle of attack with three objective functions respectively;At the third stage the maximum lift-to-drag ratio is used for glide re-entry.Finally,the results of traditional single objective function optimization are compared with the results obtained by the method programming in this paper.Based on the above methods,the simulation results show that the method of piecewise design of re-entry trajectory will obtain a more balanced value between different objective functions,effectively avoiding the disadvantage of the traditional single objective design that the objective performance is optimized by one or more performance losses.