基于PDFF的直线电机驱动XY平台H_∞交叉耦合控制

H_∞ Cross-coupled Control of Linear Motor Driven XY Table Based on PDFF

XY平台直线伺服系统中,负载扰动、机械惯性及双轴响应速度不匹配会影响轮廓加工精度,为此提出了一种将PDFF及H∞交叉耦合控制相结合的控制策略。单轴速度控制器采用兼顾快速性和鲁棒性的PDFF控制,间接减小轮廓误差。并在X、Y轴间引入交叉耦合控制,将基于PDFF的XY平台交叉耦合控制框架等效为一反馈系统,采用H∞次优方法设计交叉耦合控制器,直接减小轮廓误差。仿真结果表明该控制方案可增强系统的鲁棒性,提高系统的快速性和轮廓加工精度。

To weaken the influences of load disturbances, mechanical inertia, and the speed mismatch between X axis and Y axis to the contour precision of XY table linear servo system, a control scheme combining PDFF control with H∞ cross-coupled control is presented. PDFF control method that can give attention to robustness and rapidity at the same time is used to design the monoaxial speed controller to reduce contour error indirectly. A cross coupled controller is introduced between X axis and Y axis. The frame of XY table cross-coupled control based on PDFF is equivalent to feedback system, and H∞ suboptimum control is adopted to design cross-coupled controller to reduce contour error directly. The simulation results show that the proposed control scheme not only can enhance the robustness to load disturbances, but also has high tracking performance and contour precision.