互相关直径测量的相位跟踪采样控制与校正

PHASE TRACKING SAMPLING CONTROL AND CORRECTION FOR CROSS CORRELATION DIAMETER MEASUREMENT

为了提高互相关法直径测量的精度,需要对工件表面误差信号进行等相位间隔跟踪整周期采样。介绍分频法实现相位跟踪采样控制的原理;对相位间隔准确度的影响进行了讨论,提出固有误差和随机误差的概念,对其产生原因进行了分析;引入附加角测量环节对采样相位间隔进行校正,给出校正算法;结合ARM7LPC2148 MCU嵌入式系统,介绍相位跟踪采样控制、校正测量及同步的具体实现。实验测试表明:转速频率波动大于千分之一,采样控制系统的分频系数即会发生改变,相位跟踪性良好;在3 000转/分以下,采样相位间隔误差控制在0.001 13度以内;证明附加角测量和采样相位间隔校正是必要的。

In order to improve the accuracy of cross correlation diameter measurement,it is necessary to track the workpiece surface error signal by integer period and equal phase interval sampling. This paper introduces the principle of phase tracking sampling control by frequency division method. The influence of phase interval accuracy is discussed,and the concept of inherent error and random error is proposed,and the cause of the error is analysed. We introduce the additional angle measurement link to correct the sampling phase interval,and give the correction algorithm. Based on the ARM7 LPC2148 MCU embedded system, we introduce the implementation of phase tracking sampling control,calibration measurement and synchronization. Experimental tests show that the frequency division of the sampling control system will change and the phase tracking is good when the frequency fluctuation of the speed is greater than 1/1 000. At3 000 r/min,the sampling phase interval error is controlled within 0. 001 13 degrees. It is necessary to prove that the additional angle measurement and the sampling phase interval correction.