数控机床丝杠动态误差补偿分析研究

Research on Dynamic Error Compensation of Ball Screws of CNC

针对机床定位误差补偿研究大多是通过实验反推模型,补偿模型复杂且鲁棒性较差,难以在实际生产中应用。分析了滚珠丝杠副各部分热源的传热机制,提出包含移动热源的一维离散化非稳态热传导模型;随后,分析滚珠丝杠副误差形成机制,建立基于滚珠丝杠副几何螺距误差和热误差的综合补偿模型;最后,设定运行工况进行数值仿真,并通过试验进行验证。试验结果表明,丝杠在运行至20、40 min时的累积定位误差从补偿前的110μm、169μm变为补偿后的8μm、6.7μm。在省去实验的情况下其动态累积误差平均降低了94%,达到了较好的补偿效果。

Many researches on building model of positioning error compensation of CNC are based on lots of experiments,the compensation model is complex and has poor robustness,so it is difficult to be applied in practical.An one dimensional unsteady discrete model including moving heat source generated by ball screw is proposed based on heat transfer analysis of the ball screw;Then,study the error forming mechanism of the ball screw,and a comprehensive error compensation model based on geometric pitch error and thermal error of the ball screw is established;Finally,the operating conditions are set up for numerical simulation and the result is verified by experiments.The results showed that the cumulative positioning error of the ball screw at 20、40 min changed from 110μm、169μm before compensation to 8μm、6.7μm after compensation.The dynamic error was reduced by an average of 94%without experiments.