基于干扰观测器的机械臂连续滑模控制方法

Continuous Sliding Mode Control Method of Manipulator Based on Disturbance Observer

针对多关节机械臂的高精度轨迹跟踪问题,提出了一种基于干扰观测器的连续滑模控制方法。首先,对于系统扰动,设计了一种干扰观测器来对扰动进行实时估计以减少系统的不确定性;其次,基于高阶滑模控制思想对控制器进行设计,得到了连续的控制律,从而有效削弱了滑模控制中的抖振现象;同时,为了解决滑模控制需要预知不确定性上界的缺陷,采用自适应技术对控制律进行改进,避免选择较大的控制增益增加系统的抖振,给出了控制器的李雅普诺夫稳定性证明,并计算了系统的有限收敛时间;最后,以六自由度机械臂的前3个关节作为研究对象进行仿真分析,并与线性滑模控制方法和终端滑模控制方法进行对比,验证了所提出的控制方法的有效性。

For the problem of high-precision trajectory tracking of multi joint manipulator,a continuous sliding mode control method based on disturbance observer is proposed.Firstly,for the system disturbance,a disturbance observer is designed to estimate the disturbance in real time to reduce the uncertainty of the system.Secondly,the controller is designed based on the idea of high-order sliding mode control,and a continuous control law is obtained,thereby effectively weakening the chattering phenomenon in sliding mode control.At the same time,in order to solve the defect of sliding mode control,which is necessary to predict the upper bound of uncertainty,the adaptive technology is used to improve the control law to avoid selecting a larger control gain to increase the chattering of the system.The Lyapunov stability of the controller is proved and the finite convergence time of the system is calculated.Finally,the first three joints of the six-degree-of-freedom manipulator are used as the research object to conduct simulation analysis and compare with the linear sliding mode control method and the terminal sliding mode control method,which verifies the effectiveness of the proposed control method.