Autonomous Drifting Using Torque Vectoring: Innovating Active Safety

Recent years have seen a rapid proliferation of new concepts and technologies related to automated cars, which could significantly contribute to enhance vehicle passenger safety. Among those, autonomous drifting is a promising idea that takes the control possibilities of a vehicle beyond what is currently achievable by active safety systems such as Electronic Stability Control (ESC). This paper explores for the first time the use of torque vectoring in autonomous drifting vehicles with multiple motors. The idea is to keep the vehicle drifting along a predefined path, with desired sideslip angle and vehicle speed. Considering a rear-wheel-driven vehicle with one motor per each rear wheel, a 3-wheel vehicle model with load transfers is used. The control formulation is a feedforward action coupled with a Linear Quadratic Regulator (LQR) based on a steady-state linearization of the vehicle dynamics. Experimental results on the full-scale prototype MARTY demonstrate the actual feasibility of the concept, with very good tracking performance in steady-state conditions - as per design - and along more challenging quasi-equilibrium trajectories.