Simulation and Visualisation of Convoys

Basic Concept

At present two RailCabs operate on the NBP test track. The concept for the 1:1 realisation implies many RailCabs running in convoys. The longer a convoy the more energy will be saved. Formation of a long convoy with real RailCabs is not possible on the test track. The aim of the application is to integrate and represent real and virtual RailCabs in a simulation such a convoy is made up of one real RailCab and four simulated ones. The real RailCab runs on the test track, its position and velocity being transmitted to the visualisation unit. The other four RailCabs are simulated. The entire convoy is displayed in the visualisation.

HIL-Simulation

For simulating the RailCabs a Matlab/Simulink model was generated. The model takes into account environmental impacts such as slopes on the track and wind. The convoy is made up of one real RailCab and four simulated ones. The first RailCab in the convoy is the so-called leading RailCab. It transmits its reference velocity to all vehicles in tow. Every RailCab running behind computes its own position on the basis of the position and the velocity of the RailCab running in front. To prevent collisions the reference position is calculated from a comparison of the braking distance to the RailCab running in front.

HIL-Testbed for Convoy Controller

VR-Visualisation

For visualising a convoy the RailCabs and the NBP test track were reproduced as 3-D models.
The first RailCab of the convoy is the real one while the RailCabs running behind are represented by the simulated ones.
The visualisation displays the behaviour of the entire convoy. In this way possible collisions between RailCabs can be detected earlier. On board the RailCab on the test track there is an industrial PC which computes the simulation. For visualisation, position and velocity are transmitted via UDP protocol. The transmitted position is used to place the RailCabs on the virtual test track. The velocity serves for extrapolating the travels of the RailCabs in the event of a communication breakdown.

NBP test track with actual RailCab and VR-visualization of a convoy