基于对称恒流的应变调理技术在超动态应变观测中的应用

Super-dynamic Strain Measurement Based on Strain Signal Conditioning Method of Balanced Constant Current Excitation

应变仪作为应变信号调理器,应变仪是应变电测方法最主要设备之一。惠斯登电桥是应变仪常用的应变调理电路,具有测量精度高、灵敏度好等优点。在静态和动态应变测量中,惠斯登电桥法被广泛应用。但在超动态应变测量时,惠斯登电桥存在易耦合高频电噪声、高频信号信噪比差、测量频带窄等缺点。文中介绍了一种基于对称恒流激励的应变调理方法。与惠斯登电桥法相比,该方法能够更好地抑制高频电磁噪声、提高高频信号的信噪比和分辨率、拓宽应变信号测量频带,适合高频应变信号的调理。搭建了一套基于恒流应变调理技术的超动态应变连续测量系统。经实验测试,该系统具有宽频带、高信噪比等优点,在长时间连续高精度测量的条件下仍具有很好的可靠性和稳定性.

As strain signal conditioner strainmeter is one of the most important equipment for strain measurement. Wheatstone bridge is commonly used for strain conditioning circuit in a strainmeter,with the advantages of high precision and good sensitivity. Wheatstone bridge method is widely used in the static and dynamic strain measurement. However Wheatstone bridge has some disadvantages in the super dynamic strain measurement,such as high electromagnetic noise,low signal to noise ratio,narrow frequency band and so on. In this paper,a Balanced Constant Current Excitation method for strain signal conditioning is introduced.Compared with the Wheatstone bridge method,this method can better suppress the high frequency electromagnetic noise,improve the signal to noise ratio（ SNR） and resolution of the high frequency signal,broaden the strain signal band,which is suitable for the measurement of high-frequency strain signal. A high speed data acquisition and processing system based on the Balanced Constant Current Excitation technology for Super-Dynamic strain signal conditioning. Experimental tests demonstrate that the apparatus does provide some advantages of broadband and high SNR,which has good reliability and stabilityprovidinghigh-accuracy measurements.