2X/Y直线进给轴直线轮廓误差的学习补偿方法

Learning-based linear contour error compensation method for 2X/Y-type linear feed axes

为了提高2 X/Y直线进给轴的联动直线轮廓精度,研究了进给轴联动直线轮廓偏差的测量、评价和补偿方法。分析了直线电机驱动进给过程存在直线轮廓偏差的原因及其补偿的复杂性,给出一种基于学习的直线轮廓误差在线精密补偿方法。该方法通过激光干涉仪的2D时间基准精密测量龙门联动轴直线轮廓的实时坐标值,应用最小二乘方法评价确定理想直线方程;通过与理想直线比较得到直线偏差学习样本,建立基于最小二乘支持向量回归方法的直线偏差识别模型,以模型的在线回归计算确定偏差补偿量。最后给出了补偿量控制输出策略与补偿系统构建方案,并在自构建的直线进给轴平台上进行了在线补偿实验。结果表明,应用该方法对2 X/Y直线进给轴联动的直线轮廓偏差进行在线补偿,可使轮廓精度提高53%。

To improve the linear contour accuracy of 2X/Y gantry linear feed axes,the research of the literature focuses on the straightness accuracy measurement,evaluation and error compensation of the axes.Firstly,the cause of linear contour error in interpolation process and its compensation complexity were analyzed for a 2X/Y gantry feed axis driven by linear motors.Then a learning algorithm based compensation method was applied to increase the contour accuracy for this type of gantry axis.In the method,2D time function of a laser interferometer was utilized to acquire real-time interpolation error data and least square method was taken to evaluate and determine the ideal linear equation.A model based on least square support vector regression technique was established to recognize the errors.With the support vectors from learning process,the real-time compensation values were acquired through the model regression calculation.Finally,the compensation output strategy and corresponding realization system were also proposed.To demonstrate the procedure of the proposed approach,an experiment was conducted on the self-construction 2X/Y axis feeding platform.The result shows that the combination technique can compensate the interpolation error and increase the straightness accuracy by 53%.