关键词: 空天飞行器, 返回滑翔, 在线制导, 解析动力学, 优化算法

Abstract: This paper studies the online gliding guidance law for aerospace vehicles in the return phase. A new flight profile in the gliding phase is proposed initially, according to which the constraints on the altitude, the heading angle, the flight path angle and the range to go that are necessary for smooth transition to the terminal area energy management, can be automatically satisfied, thus reducing the number of constraints addressed in the guidance law. The accurate analytical solutions in the gliding phase are deduced. In addition, the analytical expressions of the path constraints and the performance indexes are obtained, and the dissipation in the velocity is analytically represented with respect to the range to go. Then a double loop guidance law is proposed based on these analytical expressions. In order to meet the terminal velocity, the inner loop revises the profile analytically and controls the range to go by determining the waypoint. In order to satisfy the path constraints and optimize the trajectory, the outer loop optimizes the profile with a particle swarm optimization method and an improved conjugate gradient method with analytical expressions. Finally, the numerical simulation demonstrates the effectiveness of the proposed online guidance law.

Key words: Aerospace vehicle, Reentry gliding, Online guidance; Analytical dynamics, Optimization algorithm