HYPERSONIC VEHICLE TRAJECTORY DESIGN BASED ON OPTIMAL CONTROL THEORY

摘要

The purpose of the paper is to determine the nominal trajectory of a hypersonic vehicle. Angle of attack is used as control variable to optimize the trajectory, and the problem is cast as the optimal control problem and the first order necessary condition is obtained by use of Pontriaghin Maximum Principle. It is in the form of a two point boundary value problem, and which is solved by means of the gene algorithm. Firstly the region of value of the angle of attack is obtained by solving suboptimal trajectory, then the region of initial value of the adjoint variables is estimated as a result, finally the optimal initial value of adjoint variables are obtained by gene algorithm. The aboved method is used on a hypersonic vehicle to obtain the maximum terminal velocity optimal trajectory with heat rate constraint. It is shown that the terminal velocity is larger than that of the suboptimal flight trajectory. The numerical example also shows that the gene algorithm was a perfect method to solve two point boundary value problem.