Online Monitoring System for Short Stator Maglev Train

Maglev train is a new kind of transportation mode that uses magnetic force to levitate and propel the train along a track. It is becoming more popular especially in China, where several maglev lines are in operation or under construction. Unlike the traditional wheel-based train, maglev train is suspended above the track, with a desired gap of about 8 mm. Due to the small gap, any disturbance of the suspension system may cause failure of suspension. The sources of disturbance include irregularity of track, variation in load, variation in parameters of the train structure (such as stiffness and damping of air spring), unexpected coupling vibration of the train-track-bridge system, and large displacement of the track and bridge. An online monitoring system was designed and installed on a maglev train and the corresponding line to collect the necessary data for analyzing the condition of the train and line and the mechanism of dynamic interaction of the train-track-bridge system. The monitoring items for the maglev train include the acceleration of the maglev bogies and carriages, the suspension gap, and the current of electromagnets. The monitoring items for the line include the acceleration of the bridge and track in concrete straight section, concrete curve section, tunnel wall and steel turnout. They also include relative displacement between concrete bridge and track, and strain of the track. Piezoelectric accelerometers, laser displacement sensors, fiber Bragg grating sensors and electric eddy displacement sensors are used in the monitoring system. All sensors are connected to data acquisition equipment by signal cable. The online monitoring system detected some unexpected conditions of the train and line, such as over-limit irregularity of the track, vibration resonance between the train and track, and suspension failure of the train. The data collected when the train was operating at different speeds and passing through different sections of the line was analyzed. The online monitoring system helped to speed up the debugging process before the maglev line started its official operation.