Research on Programming Algorithm of Trajectory for Hypersonic Vehicles Based on Particle Swarm Optimization

Aiming at the sensitivity to initial value and long computation time spent on iteration and programming the reference trajectory in reentry trajectory optimization for hypersonic vehicles, we propose a trajectory programming algorithm, which is based on drag acceleration profile. First of all, models of motion in reentry process of vehicle are built and an independent variable is introduced for optimization to reduce the difficulty of iterative computation. Then the optimal control problem of trajectory programming is simplified as one-dimensional searching problem including longitudinal and lateral parts. Subsequently, the tracking controller is designed for tracking the drag acceleration profile, where the particle swarm optimization is adopted in order to optimize the gain coefficient of tracking controller, from which a good tracking accuracy is obtained. Simulation results reveal that the obtained reentry trajectory presented by this paper can save the subsequently optimization iteration time and approach the best trajectory, which shows that this rational algorithm has great engineering value in practical application.