Vehicle drifting: mathematical theory and dynamic analysis for stabilised drifting of RWD vehicles

This paper introduces a mathematical definition for drifting of vehicles. A necessary kinematic condition for enabling negative body side-slip angle at centre of the front wheel during a left-hand turn is identified as drifting indicator. Dynamics of the drifting motion is investigated by means of a simplified three-wheel vehicle model in steady-state, focusing on rear wheel drive (RWD) vehicles. Drifting point is identified as an unstable equilibrium point of the nonlinear system. The equilibrium point is made stable by means of direct control only over yaw velocity, as a single key stabilising objective, and using the steady-state model as feedforward. A four-wheel planar dynamic simulation model is used together with a combined slip tyre model to investigate the accuracy of the proposed analysis. Steady-state RWD drifting motion is achieved by using the proposed method, validating the proposed dynamics analysis. Finally, the drifting metric is used to measure the amount of drifting achieved during a manoeuvre and its effectiveness is observed.