Study of ball screw system preload monitoring during operation based on the motor current and screw-nut vibration
Study of ball screw system preload monitoring during operation based on the motor current and screw-nut vibration
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DOI：
10.1016/j.ymssp.2019.05.036
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发表时间：
2019-09
影响因子：
8.4
通讯作者：
T. Nguyen;S. Ro;Jong-Kweon Park
中科院分区：
文献类型：
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作者：
T. Nguyen;S. Ro;Jong-Kweon Park
本文提出了一种通过计算螺母的轴向固有频率和相应的工作台位移来监测数控机床常用滚珠丝杠传动系统预紧力的方法。首先，我们推导了一个离散的动力学模型，并用它来研究滚珠丝杠系统预紧力的变化。其次，提出了一种通过电机电流信号和螺母轴向振动信号监测滚珠丝杠预紧力运行状态的方法。应用这种方法，通过采集和分析系统在运动过程中发生转变时的信号，构成滚珠丝杠系统的频率响应函数。这使我们能够检测滚珠丝杠传动系统的轴向固有频率。然后在系统运行时计算和监控滚珠丝杠预紧力。我们提供了一种有效和直观的方法来监控运行中的滚珠丝杠系统预紧力水平的变化。该方法特别可以用作驱动系统健康状态的指示器，通常也可以用作整个机床的健康状态的指示器。
In this paper, we propose a method to monitor the preload of an operational ball screw drive system mostly used in CNC machine tools by evaluating the natural frequency of the screw nut in the axial direction and the corresponding working table displacement. First, we derived a discrete dynamic model and used it to study the variation in the ball screw system preload. Second, we proposed a method for monitoring the ball screw preload in operational mode via the motor current signal and the screw nut axial vibration signal. We apply this method by acquiring and analyzing the signals from the system as it undergoes a transition in its motion, then compose the frequency response function (FRF) of the ball screw system. This enables us to detect the axial natural frequency of the ball screw drive system. The ball screw preload is then calculated and monitored as the system is operational. We provide an efficient and intuitive method to monitor the variation in preload level of an operational ball screw system. This method can be used as an indicator of the health status of the drive system in particular, as well as for the entire machine tool in general.