Mechatronic bond graph modelling of an automotive vehicle

Automotive manufacturers have created vehicle models but these are somewhat complex and use black boxes with numerous tables and mappings. Each model is generally valid for its own field of use and can thus produce significant differences in results outside its specific field. Moreover vehicle behaviour requires detailing and analysis during precise manoeuvres called ‘life situations'. These ‘life situations' require different models to be set up. A complete vehicle model is necessary when attempting to reproduce simulated realistic behaviours for different manoeuvres. High modelling standards are also sought when vehicle systems such as steering, suspension or braking are approached. This paper presents bond graph modelling of an automotive vehicle with 16 degrees of freedom. Although not presented here, one purpose of such a model is dimensioning of different vehicle systems, in certain life situations, using an inverse approach. The vehicle body is modelled by a rigid body with six degrees of freedom. Each wheel has two degrees of freedom, one corresponding to vertical suspension deflection, the other to wheel axial rotation. Each front wheel has one additional degree of freedom corresponding to steering mobility. Vehicle components modelled and connected to the body model are thus four suspensions, wheels and steering system. Simulations of this model have been undertaken on 20Sim. They reveal good correlation with a model simulated on AMESim by automotive manufacturer PSA Peugeot Citroën, considered as the validation reference for this study.