数控机床进给系统机械刚度的闭环参数辨识

Mechanical Stiffness Identification for Feed System of CNC Machine Tools under Closed-loop Conditions

对于高速高精度机床,进给系统机械刚度是影响机床动态特性的重要参数。以采用商用数控系统的机床为研究对象,提出了机械刚度闭环辨识的新方法。针对移动工作台机械系统的二阶系统模型,推导出全闭环条件下的刚度辨识递推公式,通过输入二次位移曲线实现系统的持续有效激励。为验证提出的机械刚度辨识方法的有效性,进行了仿真和实验,结果表明,提出的刚度闭环辨识方法不受数控系统的开放性限制,方法简便、有效,适合生产现场。

As mechanical stiffness is an important parameter and has a great influence on dynamic performance of high-speed high-precision machine tools.This paper proposed a novel method that servo mechanical stiffness can be identified under closed-loop conditions for machine tools in which popular commercial computer numerical control（CNC） system was employed.Based on 2 order control system for feeding mechanical system of worktable,an identification model for mechanical stiffness was obtained,and continuous and effective stimulation was achieved by inputting programmed displacement commands which were described as a multi-segment quadratic curve to CNC system.To verify validity of the proposed method,the simulations and experiments were performed,results show that the method is convenient,effective and suitable for commercial CNC system even closed-architecture system under industrial conditions.