Modelling and validation of the vehicle longitudinal model

This paper presents the detailed derivation and validation of a full vehicle model to study the behaviour of vehicle dynamics in the longitudinal direction. The model consists of handling and tyre subsystems, an engine model subsystem, an automatic transmission subsystem and a brake model subsystem. The full vehicle model was then validated using an instrumented experimental vehicle based on the driver input from brake and throttle pedals. Vehicle transient handling dynamic tests known as sudden braking tests were performed for the purpose of validation. Several behaviours of the vehicle dynamics were observed during braking and throttling manoeuvres, such as body longitudinal velocity, wheel linear velocity and tyre longitudinal slip, at each quarter of the vehicle. Comparisons of the experimental results and model responses with sudden braking and throttling imposed motions were made in this study. It is concluded 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.