基于变尺度法的进给系统结构参数辨识方法研究

Structural parametric identification method of a feed system based on variable scale method

机床进给系统结构参数对系统动力学建模与振动控制有着重要的影响,准确有效地识别出系统的结构参数具有重要意义。进给工作台的临界爬行速度含有丰富的特征信息,本文提出了基于工作台临界爬行速度和结构参数的函数关系,采用BFGS变尺度法优化法来识别结构参数的新方法。推导出了工作台临界爬行速度和进给系统结构参数的函数关系,建立了关于进给系统结构参数的误差函数。通过对直联式进给系统的数值仿真,验证了所提方法的可行性及准确性。结合某重型数控车床的横向进给系统,利用Renishaw测试系统得到了工作台的临界爬行速度数据,成功实现了对该进给系统结构参数的辨识,证明了所提方法简单易行,具有较高的精度。为进给系统结构参数辨识和优化提供了理论和实验参考。

Structural parameters have important effects on dynamic modeling and vibration control of feed servo systems of machine tools.It is meaningful to identify them accurately.Abundant feature information is included in the critical stick-slip velocity of a worktable.The new method of structural parametric identification was put forward by using the BFGS variable scale method,it was based on the relationship of the critical stick-slip velocity and structural parameters.The function relation between the critical stick-slip velocity and structural parameters was derived and the error function of structural parameters was established.The correctness and feasibility of the method was verified with numerical simulation of a feed system with motor directly connected.In a field testing,the cross feed system of a heavy duty CNC machine tool was employed.The data of the critical stick-slip velocity at different feed positions were obtained with a Renishaw laser interferometer measuring system.The structural parameters of the feed system were identified satisfactorily.The results provided a theoretical and experimental reference for identification and optimization of structural parameters of feed systems.