基于NDO的永磁同步电动机自适应分数阶滑模控制

Adaptive Fractional Order Sliding Mode Control for PMSMs Based on NDO

针对永磁同步电动机(PMSM)驱动的高档数控机床进给系统易受参数变化、外部扰动等不确定性因素影响的问题,设计了一种基于非线性干扰观测器(NDO)的自适应分数阶滑模控制(AFOSMC)方法。建立了含有不确定性的PMSM动态数学模型。将自适应控制与分数阶滑模控制(FOSMC)相结合,抑制了整数阶滑模控制的抖振现象,且能实时调整切换增益,提高了系统的控制精度。然而,外部干扰会对系统产生极大的影响,因此采用NDO实时辨识外部干扰,将观测值作为前馈补偿引入AFOSMC中,以提高控制器的抗干扰能力。实验结果表明,基于NDO的AFOSMC方法有效地削弱了抖振现象,提高了进给系统的跟踪性能和抗扰能力。

The feed system of CNC machines driven by PMSM servo system was susceptible to parameters variation,external disturbances and other uncertain factors,an AFOSMC scheme was designed based on NDO.First,the dynamic mathematical model of PMSM with uncertainties was established.Then,FOSMC and adaptive control were combined to suppress the chattering phenomenon of integer order sliding mode control,and the switching gain might be adjusted in real time to improve the control accuracy of the system.However,external disturbances would have a great impact on the system.Therefore,NDO was used to identify the external disturbances in real time,and the observed values were introduced into AFOSMC as feedforward compensation to improve the anti-interference ability of the controller.Finally,the experimental results show that the designed AFOSMC may weaken the chattering phenomenon effectively based on NDO,improve tracking performance and anti-interference ability of the feed systems.