精密数控机床液体静压导轨油膜波动补偿控制研究

胡均平1，胡骞1，李科军1，刘成沛1，徐大清2

(1.中南大学机电工程学院，长沙410083；2.国家电网常德供电公司发展部，湖南常德415100)

摘要：针对加工载荷作用的液体静压导轨油膜厚度波动问题，建立闭式液体静压导轨系统状态空间模型，利用精密数控机床加工载荷可预知特性，提出对静压导轨油腔压力主动预见控制策略。采用MATLAB搭建油膜波动补偿控制系统仿真模型，分析比较不加控制、采用最优控制、引入主动预见控制时导轨油膜厚度波动情况，观测两种控制方式时的油腔压力改变量。结果表明，预见控制作用下油膜厚度波动量较采用最优控制方式时减小73.3%，较不加控制减小94.1%；油腔压力对加工载荷跟随性提升23%。通过以溜板动态偏移量为指标的实测分析，验证主动预见控制策略对油膜波动补偿的有效性。

关键词：静压导轨；加工载荷；油膜波动补偿；预见控制

中图分类号:TG519.3；TH137文献标志码：A

基金项目：国家自然科学

收稿日期：2014-12-16修改稿收到日期：2015-04-21

Compensation control of oil thickness fluctuation in hydrostatic guide system of precision NC machine

HUJun-ping1,HUQian1,LIKe-jun1,LIUCheng-pei1,XUDa-qing2(1. College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;2. Development Depatment of Changde Electric Power Bureau, State Grid Corporation of China, Changde 415100, China)

Abstract:In view of the oil film thickness fluctuation in hydrostatic guide under dynamic load in mechanical processing, a state-space model of closed hydrostatic guide system was established. Considering the foreseeable characteristics of processing load in precision NC machine tool, an active preview control strategy for the oil cavity pressure was presented. By means of MATLAB software, a simulation model for the compensation control system was built. The fluctuation of oil film thickness was investigated under the conditions of no control, optimal control and active preview control. The variation of the oil cavity pressure under the optimal and active control was observed. The simulation results show that the oil film fluctuation under active preview control reduces by 73.3% compared to the case of optimal control, and reduces by 94.1% compared to the case of no control. Besides, the following performance of the cavity oil pressure on the processing load is improved by 23%. Finally, an experiment evaluating the deviation of the slider was carried out. The experiment results correspond to those of the simulation computation.

Key words:hydrostatic guide; processing load; oil film fluctuation compensation; preview control

液体静压导轨以低磨损、高刚度等技术优势广泛用于精密制造领域[1]。由于加工中导轨受动载荷作用，造成溜板与基础导轨间油膜厚度波动不定，破坏固定在溜板上被加工件与刀具间的理想位置关系，直接影响机床加工精度。为解决该问题，高殿荣等[2-3]研究节流器，试图通过改变节流器结构形式或调节方式提升油膜稳定性，但由此产生的如HCR静压控制节流器、PM预压预调型反馈节流器等结构更复杂，加工难度更大。……