直驱XY平台变增益交叉耦合互补滑模轮廓控制

Variable gain cross-coupled complementary sliding mode contouring control for direct drive XY table

针对永磁直线同步电动机(PMLSM)直接驱动XY平台存在的系统不确定性因素及双轴间耦合的问题,在建立双轴直驱平台数学模型和分析系统轮廓误差的基础上,采用将互补滑模控制器(CSMC)与变增益交叉耦合控制器(VGCCC)相结合的轮廓控制策略以保证系统实现高精密轮廓加工。CSMC作为反馈控制器,可抑制参数变化、外部扰动以及摩擦力等不确定性因素对系统的影响,保证系统的强鲁棒性。同时,引入VGCCC解决直驱XY平台间参数不匹配造成的耦合问题,VGCCC可根据轮廓误差估计模型得到的实时轮廓误差改变控制器的补偿增益值,将轮廓误差按照一定比例分配到各轴中,减小系统轮廓误差,从而实现双轴精密轮廓加工,满足系统要求的控制精确度。实验结果表明,该方法使直驱XY平台伺服系统具有较强的鲁棒性能和跟踪性能,进而提高了系统的轮廓加工精确度。

For permanent magnet linear synchronous motor(PMLSM)direct drive XY table has the problems of uncertainties and biaxial coupling.On the basis of the establishment of PMLSM mathematical model and the analysis of system contouring error,a contouring control strategy combined complementary sliding mode control(CSMC)and variable gain cross-coupled controller(VGCCC)is proposed.CSMC was designed as a feedback controller.It can suppress the influence of uncertainties such as parameter variations,external disturbances and frictions of the system,and guarantee the strong robustness.Meanwhile,VGCCC was introduced to solve the coupling problems caused by mismatched parameters between the XY table.VGCCC can change the controller's compensation gain based on the real-time contour error obtained from the contour error estimated model.The contour error was allocated to each axis in a certain proportion to reduce the system contour error,and thus the precision contour machining was realized and the control precision required by the system was met.The experimental results show that this method makes direct drive XY table has strong robust performance and tracking performance,and further improves the contour machining accuracy of the system.