数控机床直线同步电动机磁悬浮系统反馈线性化控制的研究

Research on feedback linearization control of linear magnetic suspension synchronous motor for CNC machine

由于在数控机床直线同步电动机磁悬浮系统中,直轴电流、悬浮高度与水平速度之间存在非线性耦合,以及负载扰动等不确定因素,会对控制系统产生诸多不利影响。针对该问题,提出了一种新型解耦控制方法。建立可控励磁磁悬浮直线同步电动机(controllable excitation linear magnetic suspension synchronous motor,CELMSSM)的数学模型;通过选取适当的状态变量得到该电动机的仿射非线性模型;在传统电流控制的基础上,利用非线性系统的微分几何理论,通过坐标变换与状态反馈,将电动机仿射非线性模型解耦线性化为直轴电流子系统、水平速度子系统以及悬浮高度子系统的3个可独立控制的线性子系统;根据最优极点配置法设计系统的控制规律,从而实现可控励磁磁悬浮直线同步电动机的动态解耦控制。最后,对控制系统进行仿真研究,结果表明通过反馈线性化控制与传统PI控制仿真对比,所提出的控制策略可使系统的动、静态性能得到显著增强。

In the magnetic suspension system of linear synchronous motor for CNC machine,the non-linear coupling between armature current,suspension height and horizontal velocity,as well as the uncertain factors such as load disturbance,which will have a lot of adverse effects on the control system.In order to solve this problem,it proposes a new decoupling control method.Establishing mathematical model of controllable excitation suspended linear synchronous motor(CELMSSM),get the affine nonlinear model of the motor by selecting appropriate state variables,based on the traditional current control,using the differential geometry theory of nonlinear system the nonlinear model of motor affine is decoupled and linearized into three independent linear subsystems of straight axis current subsystem through coordinate transformation and state feedback,horizontal speed subsystem and suspension height subsystem;Design the control law of the system according to the optimal pole assignment method thus realizing the dynamic decoupling of CELMSSM.Finally,the control system is simulated,through the comparison between feedback linearization control and traditional PI control simulation,the results show that the proposed control strategy can significantly enhance the dynamic and static performance of the system.