Modeling, Simulation, and Hardware-in-the-Loop Transmission Test System Software Development

This paper describes the development of a generic test cell software designed to overcome many vehicle-component testing difficulties by introducing modern, real-time control and simulation capabilities directly to laboratory test environments. Successfully demonstrated in a transmission test cell system, this software eliminated the need for internal combustion engines (ICE) and test-track vehicles. It incorporated the control of an advanced AC induction motor that electrically simulated the ICE and a DC dynamometer that electrically replicated vehicle loads. Engine behaviors controlled by the software included not only the average crankshaft torque production but also engine inertia and firing pulses, particularly during shifts. Vehicle loads included rolling resistance, aerodynamic drag, grade, and more importantly, vehicle inertia corresponding to sport utility, light truck, or passenger cars. Driver aggressiveness algorithms that compensated for sensitivity to high grade, forward/reverse driving, and extremely high speeds were also incorporated to properly track a variety of severe driving profiles. Test results validating the operation of the system against actual vehicle data is also included. The paper summarizes the elements required to accomplish these tasks.