A 3D simulation model of train dynamics for testing odometry algorithms

An accurate simulation of degraded adhesion conditions according to applicable norms with corresponding interactions with on board subsystems is also quite difficult to be performed using conventional or commercial multibody codes (degraded adhesion conditions are critical in the location algorithm testing). In order to avoid these limitations a complete three-dimensional multibody model of a railway vehicle has been developed using Matlab-Simulink™ including an efficient contact model which has been further modified in order to simulate degraded adhesion conditions: a wide variety of on board subsystems (for example WSP, anti-slip devices) is available and, as a consequence, the model can simulate various running conditions, with arbitrary tracks, including conditions that may stress the sensor behaviour, like i.e. low adhesion between the wheels and the rails, track irregularities, curves, line gradient, etc.. The use of Matlab-SimulinkTM allows testing easily the on board components with real-time implementation; for instance, considering the WSP subsystem as a safety relevant component for railway running and a device affecting directly the rotational dynamics of axles (and consequently GIT measurements), you can carry out HIL tests (Hardware in the loop) on suitable test rigs, using Matlab-SimulinkTM as a real-time simulation software. On this point you can find current regulations including all the requirements to respect in the simulation environment in order to make valid HIL tests, in a partial or full substitution of the corresponding trials on the real railway line. In addition to WSP systems, you can also test ATP/ATC systems, odometry boards, anti-skid systems, etc..