基于控制图的磨削颤振预测方法

为了预测磨削过程中颤振的发生,提出一种基于休哈特控制图的磨削颤振预测方法.该方法基于统计质量控制中所遵循的“Kσ”原则来绘制颤振传感信号特征量的控制图,以监测识别磨削振动中不稳定性信号成分,达到快速准确预测磨削颤振的目的.首先,根据磨削加工过程中颤振信号的频谱分析得到颤振发生的敏感频段,以该频段能量占整个分析频段能量的百分比作为颤振特征量.然后,以平稳磨削过程振动信号的颤振特征量为统计特性值绘制控制图,并计算其均值和方差,进而得到控制图的上、下控制界限值.最后,利用控制图的判断准则对统计特性值是否发生异常波动进行判别,从而实现颤振预测.实验结果表明:基于控制图的磨削颤振预测方法能够准确地预测颤振的发生.

Prediction Method of Grinding Chatter Based on Control Chart

To predict the grinding chatter, a prediction method of grinding chatter based on Shawkart control chart is proposed. To predict the grinding chatter quickly and accurately, this method draws the control chart of chatter sensing signal feature based on “Kσ” principle of statistical quality control to monitor the unstable signal component. First, according to the chatter signal's spectral analysis of grinding process, the sensitive frequency band of chatter was obtained. The percentage of the sensitive frequency band energy accounted for the entire analyzed band energy was regarded as chatter characteristic value. Then, the chatter characteristic values of stable grinding process vibration signals were treated as statistical characteristic values to draw control chart. By calculating mean and variance of the statistical characteristic values, the upper and lower control limits of control chart were calculated. Finally,the rules of control chart were used to distinguish whether the abnormal fluctuation of statistical characteristic values occurred. In this way, the chatter was predicted. Experimental results show that the prediction method of grinding chatter based on control chart can predict the occurrence of chatter accurately.