Frequency Acquisition Method for Measuring Strain of Vibration Wire Sensor

Methodology

The electromagnet was stimulated using the input pulse train. This stimulus is transmitted to the wire and generates an output signal that matches the resonance frequency of the target. This is called the natural vibration frequency according to the transformation of the target (Lee, Kim, Sho, et al., 2010).

Figure 1.

Measurement theory of vibrating wire sensor

A force is applied to the target to transform the natural vibration frequency. The applied force transforms the supports on both sides of the wire. Thus, the natural vibration frequency is measured differently even if the length of the wire changes only slightly, making this a sensor with high precision sensitivity.

The initial frequency of the vibrating wire sensor can be calculated using the following equation:

The frequency transformed from the target can be calculated using the following equation (Arutunian, 2008; Coutts, Wang, & Cai, 2001):

Interface

Based on the basic theory outlined in Section 2, this section describes the hardware and software architecture designs.