A modular monitoring system for onboard vehicle diagnostic

The work shows the development of a monitoring system to be installed on the vehicle, able to measure and elaborate the signals acquired on the axle boxes and the bogie of the vehicle in order to detect malfunctions of different critical components. The monitoring system has been developed to issue first level alert communications in case of failures of the components, and to provide indications concerning the conditions of the components in order to improve the preventive maintenance scheduling. The architecture has been designed considering the requirement of low system cost in order to allow its implementation on a large variety of vehicles, including freights. The result of the design can be defined as a specialized multiplexer with integrated differentiated signal conditioning, able to measure: temperature, angular velocity and the accelerations on each axle box, temperature on the brake calipers, accelerations on the coach. Using these signals, an embedded processor is able to run automatically different programs in order to verify the bearing conditions, the wheel conditions, the brake conditions, problems on the suspension system, and other aspects of the vehicle behavior, such as derailment or instability. The paper shows an application of the system on a freight bogie during running tests performed on an Italian railway line. In this first stage of development, the obtained data are stored on the unit for further analysis and can be viewed during the test using a TCP/IP connection with the unit. In future the data obtained from each unit could be shared and made available to the driver or to an operative centre. The development of this system has been realized in the project CARITAS within the Italian national research program INDUSTRIA 2015. This kind of system is expected to improve the vehicle safety by reducing the reaction time during failures and by improving the maintenance process. The system has been developed for application on regional passenger vehicle or freight, where the potential benefits are also higher. The novelty of this approach is in the fact that the developed monitoring system has been specifically studied for the railway application starting at the level of the hardware architecture. The result is that the system cannot be compared to a generic data acquisition system, but includes specific data acquisition, signal condition and elaboration for railway signals in a single unit.