A real-time data acquisition system for mechanical nanometer displacement sensors

This paper presents a new nanometer displacement sensor with a mechanical amplification structure based on flexure hinges. There are many advantages of the new sensor, such as large operating range, small size, high linearity, and low cost. In this sensor, the input nanometer scale displacement will be amplified by flexure hinges with a multi-stage enlarger configuration. Then the expanded displacement is transferred into an elastic body in which strain gauges are used to convert the deformation into electrical signal. However, after the mechanical amplification, the output electrical signal is still very weak. The effective signal is about 800 nanovolts when the original displacement changes 10 nanometers. Whether the weak electrical signal can be measured effectively will determine the final resolution and accuracy of the sensor. Since the conventional data acquisition method is not suitable in this situation, we design a data acquisition system including hardware and software implementation to measure the weak signal effectively and display the real-time data in upper PC. To test the effectiveness of the whole system, we present a series of comparison experiments. From these experiments, we can get the conclusion that the sensor we proposed has achieved the nanometer scale resolution.