多轴伺服系统的非线性PID交叉耦合轮廓控制

Nonlinear PID Cross-coupling Contour Control of Multi-axis Servo System

针对多轴伺服系统动态特性不匹配及轴间耦合带来的轮廓控制问题,在分析系统轮廓误差的基础上,将非线性PID控制器(NLPID)应用于单轴位置控制和交叉耦合控制(CCC)。对于任意轮廓曲线,非线性PID交叉耦合轮廓控制(NLPID-CCC)在加快伺服轴动态响应提高单轴跟踪精度的同时,实时估计轮廓误差后进行动态增益补偿至各轴,实现轴间信息共享减小系统轮廓误差。利用X-Y平台以典型的圆轮廓进行实验,结果表明:与变增益CCC方法相比,NLPID-CCC方法在轮廓误差的均方根值、最大值和平均值分别减少了30.77%、32.65%和30.43%,有效加快了伺服轴动态响应,提高了系统的轮廓加工精度。

In order to solve the contour control problem caused by the mismatch of the dynamic characteristics and the coupling between axis of multi-axis servo system,the nonlinear PID controller(NLPID)is applied to the single-axis position control and cross-coupled contour control(CCC)based on the analysis of the system contour error.For any contour curve,the nonlinear PID cross-coupling control(NLPID-CCC)can accelerate the dynamic response of the servo axis and improve the single-axis tracking accuracy,at the same time,the contour error is estimated in real time and then the dynamic gain compensation is performed to each axis to realize the information sharing between the axis to reduce the system contour error.Experiment results based on X-Y platform with a typical circular contour show that the contour error has decreased by 30.77%,32.65%and 30.43%in RMS,maximum and average values,which effectively accelerates the dynamic response of the servo axis and improves the contour processing accuracy of the system using NLPID-CCC structure compared with the variable gain CCC structure.