直接磁悬浮永磁直线电动机的鲁棒控制

Robust Control of Direct Magnetic Suspension Permanent Magnet Linear Motor

为了削弱直线电动机数控机床进给系统的摩擦阻力,实现无摩擦进给,提出了一种新型的直接磁悬浮永磁直线同步电动机。首先利用有限元软件Ansoft对电动机进行了建模及分析,结果表明该电动机可以产生可控的悬浮力和推力。将矢量控制分别应用于两套绕组可以实现推力与悬浮力的解耦,进而可以将电动机的伺服控制系统分成两个独立的子系统。分别针对实现进给与悬浮的特殊要求研究系统的控制策略,建立适合磁悬浮子系统和进给伺服子系统的鲁棒控制模型。对于悬浮子系统采用二自由度鲁棒控制策略,仿真结果表明该控制策略起到良好的抗干扰作用,系统的跟踪误差小,可以保持悬浮系统的稳定性;对于直线进给系统采用基于LMI的H∞鲁棒控制策略,仿真结果表明用该方法设计的进给伺服系统,既能保证系统对外部扰动具有良好的抑制作用,又能保证对参数不确定性的鲁棒性,从而实现数控机床的高性能无摩擦进给。

In order to eliminate the friction force of linear motor numerical control machine tool feed system,a new direct magnetic suspension permanent magnet linear synchronous motor（PMLSM） is put forward in this paper.First,the motor is modeled and analyzed by finite element software Ansoft,and the results show that the motor can generate the suspension force and thrust respectively and the forces could be controlled.Vector control is applied to two sets of windings,and the thrust and the suspension force can achieve the decoupling.Then,the motor servo control system could be divided into two independent subsystems.The robust servo control model of suspensions subsystem and feed subsystem is established for realization of the special requirements.Two-degree-of-freedom robust control is used for suspensions subsystem.The results of simulation indicate that the system with this controller has a good performance for restraint disturbance as well as for track of input signal.For feed subsystem presents H∞ robust control strategy based on LMI.The results show that controller based on LMI had excellent disturbance attenuation performance and model uncertainty attenuation performance.The system meets the requirement of robustness and rapidity for the friction-free feed of NC machine tools.