Ascent Trajectory Planning for Air-launched Near Space Vehicle

Abstract

To study the planning approach of low-altitude rapid ascent trajectory for air-launched near-space vehicle, the ascent trajectory was divided into four phases such as dropping phase, the first powered phase, gliding phase and the second powered phase. To climb rapidly after the dropping, the maximum normal load was applied during the first powered phase. In order to satisfy the terminal constraints of the second powered phase, the time-varying longitudinal control variable was parameterized as a piece-wise polynomial, with a lateral energy management scheme based on triangle function. A parameter-programming problem with multiple phases and constraints was formulated, and the modified particle swarm optimization was employed to solve it. The simulation results show that the constraints of load, control and separation were well satisfied; this method can provide reference trajectories with high accuracy and computational efficiency for different constraints.