Triaxial multi-range MEMS accelerometer nodes for railways applications

Abstract

For the homologation of railway vehicles, standards ([1, 2]) require the measurement of wheel-rail contact forces as well as the accelerometric monitoring of all bogies along the train. Moreover, also carbody accelerations are usually measured for assessing passenger comfort. Obviously, measuring ranges of accelerometer mounted on axle boxes, bogies and carbodies are significantly different and require different types of accelerometer. Besides the measuring range, also other requirements are important for this type of application: accelerometers have to be rugged, easy-to-configure, lownoise and sealed and, due to the possibility of having long cables (long distances between the measuring point and the acquisition system), measured signals have to be pre-amplified at the measuring point. Weight and dimensions, instead, are of less importance. In the present paper, a low cost, sealed, rugged, easy-to-configure, low-noise, amplified triaxial multi-range MEMS based accelerometer for railway applications is designed, produced, calibrated and tested on a freight train. Acceleration ranges, ±2, ±16 and ±40 g, along the three axis can be adjusted interactively and independently and the output can be set either to digital or to analog (with compensation of the cable length). In the paper the design of the acceleration nodes both from the electronic and mechanical point of view is presented. The results of the calibration and of the experimentation are also shown. © The Society for Experimental Mechanics, Inc. 2013.