挠性航天器智能模糊控制算法

Intelligent fuzzy control algorithm of flexible spacecraft

针对挠性航天器滑模变结构姿态控制器控制力矩的高频抖振问题,提出一种挠性航天器智能模糊控制算法。该算法使用模糊控制算法对航天器控制参数进行模糊化智能处理,能够有效改善控制器控制力矩的高频抖振问题。首先将模糊控制算法与滑模控制算法结合,根据切换面趋近律系数模糊化处理;然后应用连续饱和函数代替符号函数设计姿态控制器;最后通过算法到达滑模面的程度调整边界层厚度,在保证控制力矩不发生抖振情况的同时有效控制滑模面边界层的厚度。仿真结果证明,提出的智能模糊控制算法能够有效改善挠性航天器控制力矩的高频抖振问题,同时可以加快挠性航天器低阶模态振动曲线的收敛速度。

Aiming at the problem about high frequency chattering caused by flexible spacecraft′s sliding mode variable structure control torque,an intelligent fuzzy control algorithm of flexible spacecraft was proposed.Firstly,fuzzy control algorithm and sliding mode control algorithm were combined,and the exponential approach law parameters were fuzzy based on the size of switching function and derivative of switching function.Secondly,the continuous saturation function to replace symbolic function in sliding mode variable structure controller was used.Finally,the boundary layer thickness was adjusted by the sliding mode boundary′s degree.As a result,the boundary layer thickness was controlled,and the problem about high frequency chattering was solved.Simulation results demonstrate that the algorithm can improve high frequency chattering obviously and flexible spacecraft′s vibration suppression can be accomplished with faster convergence.