基于扰动观测器和改进自适应二阶快速终端滑模的PMLSM伺服系统控制

PMLSM servo system control based on disturbance observer and improved adaptive second order fast terminal sliding mode

针对永磁直线同步电动机(PMLSM)在运行时易受到摩擦力、负载扰动及环境变化等不确定影响,设计一种基于扰动观测器和自适应二阶快速终端滑模控制方法。首先,该方法在高阶滑模的基础上结合了快速终端滑模控制,有效加快了系统响应速度。其次,在二阶滑模面的基础上引入条件积分项,该项仅作用于边界层内部,能够有效避免滑模到达阶段由于积分饱和现象导致的超调量过大及响应时间过慢的问题。此外,设计自适应切换控制律,使切换增益在合理的区间内,并根据系统状态进行实时更新,从而削弱抖振现象。最后,为进一步提升系统的鲁棒性,采用扰动观测器对PMLSM系统的集总不确定性进行补偿。经实验验证,该控制方法具有良好的位置跟踪精度和强鲁棒性,且对系统抖振现象有明显削弱作用。

Permanent magnet linear synchronous motor(PMLSM)is vulnerable to uncertain influences such as friction,load disturbance and environmental changes during operation.A fast terminal sliding mode control method based on disturbance observer and adaptive second-order was designed.Firstly,the method combined the fast terminal sliding mode control on the basis of high-order sliding mode,which ef-fectively accelerated the system response speed.Secondly,a conditional integral term was introduced on the basis of the second-order sliding surface,which only acted inside the boundary layer,and could ef-fectively avoid the problem of excessive overshoot and too slow response time caused by integral saturation in the sliding mode arrival stage.In addition,an adaptive switching control law was designed to make the switching gain within a reasonable interval and update in real time according to the system state,thereby weakening the chattering phenomenon.Finally,in order to further improve robustness of the system,the disturbance observer was used to compensate the lumped uncertainty of the PMLSM system.The experi-mental results show that the control method has good position tracking accuracy and strong robustness,and can significantly weaken the chattering phenomenon of the system.