不确定机械臂系统的模糊滑模有限时间容错控制

Fuzzy sliding mode finite-time fault-tolerant control for uncertain manipulator systems

中文关键词  机械臂系统  有限时间收敛  滑模控制  模糊逻辑系统  执行器故障

英文关键词  manipulator system  finite-time convergence  sliding mode control  fuzzy logic system  actuator faults

中文摘要

      针对带有执行器故障的不确定机械臂系统, 文中提出了一种基于模糊滑模的自适应有限时间容错控制方 法, 以保证系统模型未知和外界扰动存在下期望轨迹的精确跟踪. 首先, 采用模糊逻辑系统对模型参数和外界扰动 进行逼近, 以避免对系统精确模型的依赖. 其次, 利用自适应算法对故障信号、模糊逻辑系统逼近误差进行估计, 进 而给出一种新的自适应模糊滑模控制器设计, 不仅能够较好地抑制系统的外界未知扰动, 保证闭环系统自适应参数 估计误差的有界性, 而且可有效地克服执行器故障信号对机械臂跟踪性能的影响. 进一步地, 给出了系统滑模面的 可达性分析, 并结合有限时间稳定性理论, 证明了系统位置跟踪误差信号可在有限时间内收敛到以零为中心的任意 小邻域内, 然后指数收敛到零. 最后, 仿真结果表明, 在所设计的控制方法下, 闭环系统可实现较好的稳态和瞬态性 能.

英文摘要

      An adaptive finite-time fault-tolerant control method based on fuzzy sliding mode is proposed for uncertain manipulator systems with actuator faults, which ensures the accurate tracking of the desired trajectory in the presence of unknown system models and external disturbances. Firstly, the fuzzy logic system (FLS) is employed to approximate the plant parameters and unknown disturbances, which avoids the dependence on exact model data of the system. Secondly, an adaptive algorithm is introduced to estimate the fault signal and the FLS approximation error. Then a novel adaptive fuzzy sliding mode controller is synthesized, which not only suppresses the unknown disturbance of the system and guarantees the boundedness of the estimation error of the adaptive parameters for the closed-loop system, but also effectively overcomes the influence of the actuator fault signal on the tracking performance of the manipulator. Furthermore, reachability analysis of the sliding mode surface of the system is carried out, and the proof that the system position tracking error signal can converge to an arbitrarily small domain of the origin within finite-time and then exponentially tend to zero, is then provided combining with the finite-time stability theory. Finally, the simulation results show that the closed-loop system can achieve better static and transient performances under the designed control method.