Modified Generalised Maxwell Slip Based Electro-Hydraulic Transfer Case Modeling for All-wheel Drive Vehicle Simulation

Abstract

This paper describes the modeling of a torque-on-demand transfer case and an all-wheel drive (AWD) vehicle simulation through model integration. To develop the AWD vehicle controller, reliable and robust mathematical modeling of transfer case for AWD vehicle simulation should be proceeded. However, conventional wet clutch model cannot be applied for simulating the AWD vehicle especially when clutch is fully lock up state because of the chattering response of torque followed by the change of external factors. By replacing a slip-regulation equation of lock-up state with a degree of freedom (DOF) reduction equation in the generalized maxwell slip (GMS) model, the chattering and instability issue of original GMS model for AWD vehicle simulation was solved in this study. For parameter verification of the wet clutch, the simulation of the transfer case module and validation with the experimental data were conducted first. Then, the simulation of an AWD vehicle was conducted through the integration of the developed one in CarSim software. Through the comparison of the modified GMS model with the original GMS model, the former is verified to be superior to the latter for stable simulation.