探测器软着陆小行星的自适应超螺旋控制

Adaptive supper-twisting control for spacecraft soft landing on asteroids

针对探测器软着陆小行星的轨道控制问题,本文提出了一种基于自适应超螺旋算法的控制方法,避免了传统滑模控制的高频抖振,并且结构简单、无需已知外界扰动时间导数的上界。首先,将软着陆的轨道控制问题描述为一类非线性系统的镇定问题。其次,基于球谐系数法表示的小行星引力场模型设计前馈控制律,将系统解耦为三个滑模函数的一阶子系统。然后,针对每个子系统设计自适应超螺旋控制器,并证明闭环系统的稳定性。最后,将本文提出的控制方法与传统的自适应滑模控制进行了对比仿真,结果表明,所提出的算法能使系统更快地收敛到滑模面上,同时有效抑制抖振效应。

In order to alleviate the chartering problem of the traditional sliding model control,an adaptive supper-twisting controller was designed for the spacecraft soft landing on asteroids.The controller has a simple algorithm structure and does not need to know the upper bound of the external disturbance＇s derivative.First,the control problem of soft landing was formulated as the stabilization of a nonlinear system.Second,a feedback control based on the spheric harmonic expansion model of the asteroid gravity was applied to decouple the system.Then,three adaptive supper-twisting controllers were designed to stabilize the subsystems.Simulations of soft landing on the Eros433 were performed to verify the effectiveness of the proposed controller.The simulation results were compared with the traditional adaptive sliding mode control to show the advantages of the proposed controller.