Modelling and Validation of the Vehicle Longitudinal Model

Abstract

This paper presents the detailed derivation and validation of a full vehicle model tostudy the behaviour of vehicle dynamics in the longitudinal direction. The modelconsists of handling and tyre subsystems, an engine model subsystem, an automatictransmission subsystem and a brake model subsystem. The full vehicle model was thenvalidated using an instrumented experimental vehicle based on the driver input frombrake and throttle pedals. Vehicle transient handling dynamic tests known as suddenbraking tests were performed for the purpose of validation. Several behaviours of thevehicle dynamics were observed during braking and throttling manoeuvres, such asbody longitudinal velocity, wheel linear velocity and tyre longitudinal slip, at eachquarter of the vehicle. Comparisons of the experimental results and model responseswith sudden braking and throttling imposed motions were made in this study. It isconcluded that the trends between simulation results and experimental data were found to be almost similar with an acceptable level of error for the application at hand