Compact Vibration Measuring System for in-vehicle Applications

Low frequency vibration occurs especially in ground transportation. It is of permanent interest in studies of driver's and passenger comfort issues and seating dynamics research. Piezoelectric accelerometers commonly used for vibration measurement are not suitable, hence other sensors capable of measuring accelerations down to sub-hertz region have to be used. Based on some previous experience with MEMS acceleration sensors a compact measuring system employing two three-axial MEMS accelerometers interfaced via a data acquisition unit to a light-weight notebook was designed and constructed. The digitised data were processed by scripts by Matlab ® with the aim to analyse both the vibration influence on seated person and the dynamic properties of the seat. Some preliminary results from illustrative test runs with a passenger automobile are presented.