Measuring vibration-induced variations in pressures between the human body and a seat

When measuring total dynamic forces between the human body and seats during vibration, variations in force over the buttocks and the thighs have previously been ignored. In this study, sensors in a pressure mat were calibrated by applying static and dynamic pressures through foam and calculating transfer functions between the applied pressures and the outputs of the sensors. This provided static calibration of individual pressure sensors and dynamic calibration of groups of pressure sensors. Measurements of dynamic pressures were used to calculate the vertical forces over the ischial tuberosities, middle thighs, and front thighs and compare with similar measurements obtained by another method. Dynamic calibration of the pressure mat reduced errors in the total dynamic force to 10% at frequencies less than 5 Hz and less than 30% at frequencies between 5 and 15 Hz. Recommendations are offered for measuring dynamic pressures between the human body and seats in vibration environments. Relevance to industry: Dynamic pressure distributions at seat interfaces influence sitting comfort during whole-body vibration. Understanding of the dynamic performance of pressure sensors and recommendations on calibrating and using pressure sensors in vibration environments can assist seat design and other situations where dynamic pressure measurements are of interest.