Calibration of a multicomponent MEMS sensor for vibration monitoring of rolling bearings: broad-band and amplitude traceability up to 20 kHz

In the field of vibration monitoring and control, the use of low-cost multicomponent accelerometer sensors is nowadays increasingly widespread. Low-cost multicomponent sensors allow implementing monitoring systems and networks (even very extensive ones) supported by a very large number of sensors, with low management costs, low power consumption, light weight and small size. In many advanced engineering applications, such as defects prevention and malfunctioning of systems, smart industries development, automation and machine learning managing, it is often necessary to "densify" the spatial resolution of the surveys, to detect more in detail the occurring dynamic phenomena, under investigation. However, for the monitoring systems to provide trustworthy and actually meaningful data, the reliability of sensors is an essential requirement. As a consequence, traceable calibration methods for multicomponent accelerometer sensors, including the appropriate uncertainty evaluation, are necessary to guarantee the reliability in the frequency domain of data provided. Proper metrological characterizations and calibration of these sensors allows to define the reliability in terms of sensitivity, with respect to mechanical reference standards, traceable to SI units. At present, the sensitivity parameters provided by the manufacturers are not traceable and often referred to static conditions only: dynamic response, as a function of frequency, is often barely known or completely disregarded. In this paper, a dynamic calibration procedure is applied to provide the sensitivity parameters of a low-cost multicomponent accelerometer sensor prototype, designed, developed and realized at the University of Siena, conceived for rolling-bearings vibration monitoring, in a broad frequency domain, from 10 Hz up to 20 kHz. The calibration procedure is performed by comparison to a reference transducer (in analogy to ISO Standard 16063-21).