| Real-time driving simulation requires accurate prediction of the Powertrain dynamic response. Development of a model for real-time driving simulation involves the following challenges: (1) develop simple, yet computationally efficient models of all important components of a Powertrain, and (2) model interactions between the Powertrain and the vehicle that influence the vehicle ride and handling behaviors significantly.; In this work, a simple and efficient real-time Powertrain model was developed using AUTOSIM, to be used in a driving simulator. The model consists of three major components: a lumped-parameter driveline torsional dynamics model, a 6-DOF engine-mounting system model and a driveshaft (including CV joints) model. This model includes the following four important interactions: (1) driveline torsional dynamics with vehicle longitudinal dynamics, (2) driveline torsional dynamics with engine-block rigid-body dynamics, (3) engine-block rigid-body dynamics with vehicle rigid-body dynamics through compliant mounts and (4) the engine-block with front unsprung masses, due to kinematical constraint applied by driveshafts.; The major contributions of the study presented in this dissertation are listed below. (1) Development of modeling methods for an engine-block equipped with a roll restrictor. Two options are included: physics-based model and modal analysis model. Three modeling methods were proposed for physics-based version of the engine-block mounting system, i.e., 12-DOF Model, 6-DOF Model A and 6-DOF Model B. Three models were compared using ABAQUS modal analysis and dynamic analysis and Model B was chose to be used in the powertrain model in this research. (2) Development of a driveshaft model to calculate the axial force generated by a tripode joint. This model is based on kinematical analysis and friction law. With this driveshaft model included, the shudder phenomenon can be studied by full-vehicle simulation.; The developed powertrain model was included into a full-vehicle model. This model was validated by comparing predicted acceleration performance of a vehicle with experimental data from tests. Simulations and parametric studies of straight-line acceleration scenarios were performed. The following conclusions were reached: (1) In a front wheel drive (FWD) automatic-transmission car, the vehicle's response to a throttle tip-in is not sensitive to the driveline compliance. (2) The engine-block rigid-body motion has significant influence on the vehicle ride response to three excitations: throttle tip-in, tripode joint axial force and road disturbance. Finally, it was demonstrated that a full vehicle model, incorporating the powertrain model, can be used as a virtual design tool. Great cost and design time savings can be achieved by using this design tool. |
