一种地外天体着陆凸轨迹曲率滑模制导方法

A convex trajectory curvature sliding mode guidance method is proposed for complex extraterrestrial body surface landing. Considering the influence of the shape of the landing trajectory on the security，the curvature constraint is introduced into the design of the sliding mode surface. The landing trajectory is a three-dimensional convex trajectory when the spacecraft system is located on the sliding mode surface. Firstly，according to the equivalent transformation and relaxation of the curvature constraint，the curvature relaxation term is proposed. The curvature sliding mode surface is designed by using the curvature relaxation term，which effectively satisfies the condition of three-dimensional convex trajectory. Next，the curvature sliding mode feedback guidance law is derived，and the sliding mode state converges to zero in finite time. Under the action of the designed guidance law，the spacecraft will complete the precise soft landing in the convex trajectory state. Finally，the effectiveness and robustness of the proposed algorithm are verified by Monte Carlo simulations.