基于干扰观测器的机械臂自适应模糊滑模控制

Adaptive fuzzy sliding mode control of manipulator based on disturbance observer

  • 摘要: 机械臂在轨迹跟踪控制中存在建模误差和外界干扰等问题。为了提高机械臂轨迹跟踪的精度和速度,设计了一种基于干扰观测器的机械臂自适应模糊滑模控制策略。首先,使用新型趋近律来减小机械臂滑模控制系统中抖振的影响;其次,采用干扰观测器对机械臂建模误差和外界干扰进行估计,根据干扰观测器的观测值对机械臂的输入力矩进行补偿;最后,对于无法观测的部分,采用模糊系统中的万能逼近原理对未知的干扰进行估计,进一步提高机械臂的轨迹跟踪性能。通过仿真试验表明,该控制策略不仅可以克服建模误差和外界干扰所带来的影响,还可以有效地削弱系统的抖振,保证了机械臂各关节位置跟踪的精度和速度。同时也说明了该控制策略的有正确性和有效性。

     

    Abstract: There are some problems such as modeling error and external disturbance in trajectory tracking control of manipulator. In order to improve the accuracy and speed of trajectory tracking of manipulator, an adaptive fuzzy sliding mode control strategy based on disturbance observer is designed. Firstly, a novel reaching law is used to reduce the influence of chattering in the sliding mode control system of the manipulator. Secondly, a disturbance observer was used to estimate the modeling error and external interference of the manipulator, and the input torque of the manipulator was compensated according to the observed value of the disturbance observer. Finally, for the unobservable part, the unknown disturbances are estimated by the universal approximation principle in fuzzy system, which further improves the trajectory tracking performance of the manipulator. The simulation results show that the control strategy can not only overcome the influence of modeling errors and external disturbances, but also effectively weaken the chattering of the system, and ensure the accuracy and speed of the position tracking of each joint of the manipulator. It also shows that the control strategy is correct and effective.

     

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