基于奇异摄动法的 FFFSR 全局滑模跟踪控制及 ESO 振动抑制

摘要

Joints trajectory tracking control and flexible vibration active suppression techniques for a free-floating flexible space robot (FFFSR)were discussed under parameter uncertainties and bounded disturbance.A composite controller containing a slow control subsystem for joints trajectory tracking control and a fast control subsystem for describing flexible vibration was proposed using the singular perturbation method.In the slow subsystem,an improved global sliding mode function with a low-pass filter to suppress sliding mode chattering was designed to achieve global robust and fast convergence of joints trajectory tracking.The fast subsystem adopted an extended state observer (ESO)to estimate coordinate derivatives of flexible modes and uncertain disturbance measured hardly,and used LQR method to suppress the flexible vibration.Numerical simulation results demonstrated the feasibility and effectiveness of the proposed control strategy.%针对存在参数不确定性和有界干扰的情况，讨论了自由漂浮柔性空间机器人（FFFSR）关节轨迹跟踪控制与柔性振动主动抑制的问题。利用奇异摄动法将系统分解为关节轨迹跟踪的慢变子系统和描述柔性振动的快变子系统，进而提出含慢、快变控制项的组合控制器；设计一种改进的全局滑模函数，利用低通滤波器抑制滑模抖振，实现全局鲁棒、快速收敛的关节轨迹跟踪；对于快变子系统，采用扩张状态观测器（ESO）对不易测量的柔性模态坐标导数和不确定扰动进行估计，并结合 LQR 方法，对柔性振动进行主动抑制。数值仿真表明，该组合控制器可以在有效抑制柔性振动的同时实现对期望关节轨迹的稳定跟踪。