Car-Trailer Dynamics: Modelling for Parametric Study on System Stability

To improve load carrying capability, passenger cars can be equipped with trailers that may significantly modify the dynamic behaviour of the vehicle alone (e.g., inducing the trailer sway oscillation). The present paper aims at providing a nonlinear model for describing the steady-state and the transient handling behaviour of a car combined with a single-axle trailer. The proposed models can be used to perform parametric studies on the geometrical and inertial characteristic of the trailer. A linearised version of the model is derived and adapted in order to match the results of the nonlinear model during ramp and step steer tests. Moreover, the linear model allows the assessment of system stability and the identification of critical speeds depending on the trailer configuration. Finally, the most relevant model parameters and assumptions for an accurate physical description of the trailer sway are identified and underlined in the paper.