基于LMI的直线伺服滑模位移跟踪控制

LMI-Based Sliding Mode Displacement Tracking Control for Permanent Magnet Linear Synchronous Motor

由于直线伺服系统应用在一些高响应、高精度场合时,永磁直线同步电机的电流和速度各自的动态过程在时间尺度上相对接近,所以采用常规矢量控制下的三闭环PID控制方法进行静态解耦会因电流和速度之间存在的非线性耦合影响系统的跟踪品质。该文提出一种基于线性矩阵不等式(LMI)的滑模控制方法对直线伺服系统进行位移跟踪控制,并将电气子系统和机械子系统作为整体进行控制,利用LMI设计其滑模控制律。通过设计扩张滑模观测器对负载扰动进行鲁棒观测,以保证系统的跟踪性能。通过实验对该算法与三闭环PID控制方法进行对比验证,证明了该方法具有良好的鲁棒跟踪能力。

When the linear servo system was used in some high-response and high-accuracy occasion, permanent magnet linear synchronous motor’s time scale of the dynamic process of the current was close to that of its speed. Hence, if the three closed-loop PID control method based on traditional vector control was employed for static decoupling, tracking performance would be compromised due to non-linear coupling between current and speed. To address this problem, a LMIbased sliding mode control scheme was proposed in this paper for displacement tracking control in the linear servo system. The electronic sub-system and the mechanical sub-system were controlled as a whole. The sliding mode control law was designed via linear matrix inequalities(LMIs).The extended sliding mode observer was designed to observe the load disturbance robustly for ensuring the system’s tracking performance. Experiments are performed to compare with the three closed-loop PID control method. Results demonstrate that the proposed method achieves more robust performance and faster dynamic response.