Intelligent sensor for monitoring freight-waggon working conditions

Abstract

Abstract A sensor system is described that monitors a railway waggon on-line in terms of the strain affecting its chassis and its freight. Making use of standard microcontroller techniques, it interrogates sensors detecting different physical parameters, correlates the received data, initiates actions and communicates remotely with stationary control equipment. The incorporation of a novel SAW component (‘ID-tag’) will allow vehicle identification and wireless alarm calling. As an example, an acceleration measurement has been incorporated, from which the velocity of colliding waggons in shunting events is derived. With the waggon coming to a standstill after the collision, the evaluation algorithm, working from threshold triggering and short-term signal integration, gives the speed of approach directly. Practical tests at a train-shunting track have proved the sensor system to be more versatile and accurate than standard pendulum sensors. Mechanical low-pass filtering by soft suspension of the acceleration sensing device was found to be useful for suppression of local waggon-body oscillations, which do not contribute to the center-of-gravity motion but take a lot of the acceleration signal headroom.