大型回转工作台导轨油膜厚度控制方法研究

Control Method for Oil Film Thickness of Guide Rail of Large Static Pressure Workbench

静压回转工作台导轨油膜厚度随载荷、切削力、油温、黏度等时变工况因素的变化而改变,导致其厚度偏离目标值,影响工作台回转精度。研究油膜厚度的调节方法,对保证零件加工精度具有很重要的工程实际意义。针对变频调速供油的静压回转工作台,分析油膜厚度形成原理及特性,采用工况系数法和3次插值法分别建立了2种油膜厚度控制模型,建模时综合考虑工作台结构尺寸、外载荷及油液黏度等参数的影响。采用米依DT3300电涡流传感器测量系统与Siemens 840DSL数控系统,搭建了油膜厚度检测与调节综合实验平台,通过?2 500 mm静压工作台变载荷实验,验证了两种控制模型对不同载荷下油膜厚度调节的合理性和可靠性,为静压工作台油膜厚度的研究提供了参考。

The oil film thickness of static pressure workbench varies with the change of working load,temperature,viscosity and other time-varying condition factors,which will make the thickness deviate from the target value and then affects the accuracy of the workbench.Therefore,the research on oil film thickness adjustment method has greatly practical significance for ensuring the machining accuracy of parts.In view of the static pressure workbench with variable frequency speed regulation,the formation principle and characteristics of oil film thickness were analyzed and two kinds of oil film thickness control models were established by using the method of working condition coefficient and the cubic interpolation respectively.The influences of varying working conditions were taken into overall consideration such as the structural size of the worktable,the external load and the viscosity of the oil when adjusting the oil film thickness.The electrical eddy current system DT3300 and Siemens CNC system 840DSL were employed to build an integrated experimental platform for the measurement and adjustment of oil film thickness.Through the regulating test of a practical static pressure workbench with a diameter of 2 500 mm,the rationality and reliability of the two kinds of control modes are verified,which provide reference for the research on oil film thickness of other static pressure workbench.