A customized system for whole-body vibration measurement

This manuscript describes the technical components and performance of a custom whole-body vibration (WBV) instrumentation system designed for autonomous, prolonged field measurement. The study demonstrated the technical readiness of the system's accelerometers. The system integrates a Teensy 4.1 microcontroller, triaxial microelectromechanical system accelerometers, force sensing resistors, global positioning system module, and microSD data storage. The accelerometers were validated against reference accelerometers commonly used in field-based WBV measurement using a motion simulator programmed with complex vibration input profiles specified in ISO 7096:2020 Earth-Moving Machinery-Laboratory Evaluation of Operator Seat Vibration for testing operator seat vibration in earth moving machinery. In the time domain, accelerometers in the custom WBV instrumentation system exhibited ≤ 2.21% error in root-mean-square (RMS) amplitude measurements and < 0.03 g sample-to-sample RMS deviation from the reference accelerometers. Frequency-domain analysis (1/3-octave band) suggested slight underestimation of signal power at low frequencies (≤10 Hz), but the differences were practically small at each 1/3-octave band. Ultimately, the system will enable WBV monitoring in settings in which operators are remote and/or the schedule of machine operation is variable (e.g., agriculture). Future work will focus on real-world validation and exploring use of the force sensing resistors to characterize operator posture, further enhancing the system's utility in occupational WBV exposure monitoring.