Asteroid Soft Landing Control Method based on Fuzzy Optimization Parameters
摘要: 针对传统指数趋近律变结构控制中抖振的问题,设计出新型变速指数趋近律滑模控制器。基于小行星软着陆控制系统的动力学模型,推导出指数趋近律滑模控制器结构。通过实时分析运动点距离滑模面的位置及趋近速率,采用模糊参数优化策略动态调整切换增益,实现在滑模面外时加快响应速度并增强系统克服摄动及外部干扰能力,到达滑模面时柔化控制量以消除抖振的目的。通过Matlab仿真,结果表明变速趋近律不仅保证到达运动的快速性,且有效降低了系统抖振,具有良好的稳态性能。Abstract: In order to solve the shaking of sliding mode control based on conventional exponent trending law, a new sliding mode controller based on variable rate trending law is designed. Based on the dynamic model of an asteroid soft landing control system, the structure of sliding mode control based on conventional exponent trending law is deduced. Through analyzing the distance of moving point and sliding mode surface, a fuzzy optimization parameters strategy based on dynamic adjustment switch gain is used, which realizes speeding up the response speed and enhancing the system capacity of overcoming the perturbation and external disturbance when the moving point is far away from the sliding mode surface and eliminating chattering when the moving point is close to the sliding mode surface. The simulation results based on MATLAB show that the sliding mode controller based on variable rate trending law not only guarantees the rapidity of movement, but reduces the shaking of system, thus it has a good stability.