Four-wheel-drive powertrain models for real-time simulation

Dynamic vehicle powertrain models have been formulated by many researchers for particular applications, mainly the analysis of powertrain characteristics or vibration. In this paper, we formulate models of four-wheel-drive vehicle powertrains for the purpose of real-time simulation. While not encompassing the complete characteristics of powertrain operation, these models are applicable for use in vehicle simulators, and include both the differential and lock-up modes of four-wheel-drive transfer case operation. The models of four-wheel-drive powertrains are applied to a particular vehicle, the US Army High Mobility Multipurpose Wheeled Vehicle or HMMWV, in order to compare and contrast both the simulated vehicle performance and the computational complexity of the models. The HMMWV powertrain incorporates a wide variety of components including: automatic transmission, torque converter, worm-gear differentials, transfer case for both differential and lock-up operation, and final-drive speed reducers at the wheel hubs. Thus the simulation of this vehicle indicates the wide application of the developed models. 9 refs