Rail vehicle control system integration testing using digital hardware-in-the-loop simulation

Control systems for converter-controlled rail vehicles are orders of magnitude more complex than controllers for previous generations of vehicles. While the dynamic behavior of previous generations of vehicles was to a large extent determined by its power components alone, an important part of the dynamics of modern vehicles is shaped by real-time software, distributed computing and intercontroller communication. To ensure proper operation of the vehicle on track, an integration test of the vehicle control system is performed before initial roll-out. In order to achieve a maximum test depth and to minimize risk and cost, this test is achieved by connecting the original vehicle control system to a real-time dynamic vehicle simulator in closed-loop operation. The paper describes concept, evaluation, and operation of a digital hardware-in-the-loop simulator for testing control-relevant parts of the vehicle. Particular emphasis is put on the hybrid nature of the underlying simulation problem and its inherent causality variations due to the combination of discrete switching effects, e.g., in diodes and controlled converters, with continuous system parts, e.g., differential equations for currents or mechanical system parts