Improving calibration accuracy of a vibration sensor through a closed loop measurement system

A sensor is a transducer whose purpose is to sense (that is, to detect) some characteristic of its environments. It detects events or changes in quantities and provides a corresponding output, generally as an electrical or optical signal. It has been widely used in mechanical engineering, aeronautics and astronautics engineering, industrial control, etc. Sensors play important roles in industries such as manufacturing, where all require the sensor to act as a reliable unit [1], [2]. In practical engineering applications, a sensor is often used for measuring vibrations, including acceleration, velocity, and displacement. It is the primary link in achieving conversion, processing, recording, and storage of information. Therefore, its performance directly influences the reliability and accuracy of the entire system. The calibration for vibration sensors, which need to ascertain sensitivity, frequency response characteristics, amplitude linearity, etc., are required before the measurement is made [3], [4]. Traditionally, an open loop device (in which the excitation signal is adjusted manually and the parameters are recorded manually) is used for sensor calibration. This type of manual calibration generates a large amount of work and active jamming, which results in errors. If a closed loop calibration system can be designed (i.e., the excitation signals are adjusted automatically by devices, and the real time data are sampled and analyzed), it will offer abundant measurement information and analysis methods which can help improve calibration accuracy and efficiency. In this article, we introduce such a closed loop calibration system for vibration sensors.