Aerodynamic drafting in overtaking games

Drafting aerodynamics are an integral part of motor racing. The contested overtake involves the exploitation of the vehicle and tyre characteristics, the track topology and the vehicular aerodynamics. When two or more vehicles are involved in a race, overtaking manoeuvres become a non-cooperative dynamic game. In contrast to an uncontested single-car scenario, in which the aim is to complete a given number of laps in minimum time, the racing objective is to win. The game described here adopts the well-known Stackelberg structure and is solved as a sequence of interlinked optimal control problems. The interactions between racing vehicles are subject to collision avoidance and near-field aerodynamics. In this study, the vehicles travel on the highly-banked Darlington raceway used in NASCAR. Collision avoidance is accomplished using a set of control barrier functions. While this study has several components, the emphasis here is on drafting aerodynamics. The results reveal interesting features of racing games that involve close-proximity ‘drafting’ aerodynamics.