基于超声波A/D采样法的相位差位移测量方法

A Method of Phase Difference Displacement Measurement Based on the Ultrasonic A/D Sampling

为了提高超声波位移测量分辨率，提出一种基于超声波A／D采样法的超声波相位差位移测量方法，利用超声波信号的相邻采样数据之差，消除了超声波信号中的直流成分对相位差位移测量的影响，再通过不同相邻采样数据之差的比值建立了相位差位移测量的数学模型，由此获得较高的相位差位移测量分辨率。该方法的采样电路简单，不需要高倍数超声波信号采样率，仅需在一个超声波信号周期里采样10几个数据，就可获得亚微米级的位移测量分辨率。实验结果验证了该方法的有效性。基于该方法研制的超声波位移测量平台，若超声波频率选用40kHz，则位移测量分辨率可达1μm。

In order to improve the resolution of ultrasonic displacement measurement, a kind of method of displacement measurement on ultrasonic phase difference based on the ultrasonic A/D sampling is proposed. The method can eliminate the impact of DC component on displacement measurement by the subtraction of adjacent ultrasonic sampling data. Then, a mathematical model of displacement measurement on phase difference is set up, which is established by ratio of the difference between adjacent sampling data and on which the higher resolution of displacement measurement is obtained. Using above method, the sampling circuit is simple and the lower ultrasonic signal sampling rate is needed, and with only a dozen of data in a period of ultrasonic signal, the submieron level of resolution of displacement measurement can be obtained. The result of experimental data shows that this method is effective, and if the ultrasonic frequency 40 kHz is selected on the platform of ultrasonic displacement measurement by the method, the resolution of displacement measurement with 1μm will be reached.