基于惠斯通电桥的弯曲应变测量灵敏度研究

Strain measurement sensitivity based on Wheatstone bridge

惠斯通电桥广泛应用于现代测量技术以及自动控制领域,本文从理论上分析了惠斯通电桥电压灵敏度与组成电路中各元件参数的关系,讨论了影响电桥电压灵敏度的几个关键因素,得出获得最大电压灵敏度的参数条件。分析结果表明:惠斯通电桥的电压灵敏度主要由桥路相邻两侧电阻的比值决定,等臂电桥具有最大灵敏度。同时,考虑到桥路输出电压与组成电路中的电阻相对变化率具有非线性,使用电阻应变片并采用半桥差动方式来搭建实验测试装置,以消除桥路电压非线性带来的影响。最后,利用自主搭建的半桥差动电桥对不同弯曲应变状态下的测量电压灵敏度进行了实验测试。实验结果表明,通过半桥差动连接方式,弯曲应变状态下桥路电压随应变程度呈线性关系。

Wheatstone bridges are widely used in modern measurement technology as well as in the field of automatic control.This paper theoretically analyzes the relationship between the voltage sensitivity of the Wheatstone bridge and the parameters of the components in the composed circuit,discuss several key factors affecting the voltage sensitivity of bridges,and derive the parameter conditions for obtaining the maximum voltage sensitivity.The analysis results show that the voltage sensitivity of the Wheatstone bridge is mainly determined by the ratio of the resistances on the adjacent sides of the bridge,and the equal-arm bridge has the maximum sensitivity.At the same time,considering the nonlinearity of the bridge output voltage and the relative rate of change of the resistance,this paper build an experimental test device using resistive strain gauges in a half-bridge differential way to eliminate the influence of the bridge voltage nonlinearity.Finally,in this paper,the half-bridge differential bridge was built independently to measure the voltage sensitivity under different strain states.The experimental results show that the bridge voltage is linear with the degree of strain in the bending strain condition through the half-bridge differential connection method.