Integrated control of wheel drive—brake torque for vehicle-handling enhancement

Abstract

Wheel torque control is an effective means of improving vehicle handling and stability. Brake-based electronic stability programs which intervene in extreme situations to regulate vehicle behaviour are the most common form of wheel torque control. With the advent of advanced driveline technologies, wheel torque control can also be achieved by the differential distribution of available drive torque to all four wheels. Similarly, in combined cornering and braking manoeuvres, the applied brake input can be differentially distributed to regulate vehicle handling. This paper proposes an integrated scheme for wheel torque control that combines differential drive or brake torque distribution with the emergency braking control to regulate the vehicle yaw rate and side-slip angle. A wheel torque controller was developed using a non-linear predictive control theory, an eight-degrees-of-freedom vehicle model, and non-linear tyre models. The simulated vehicle responses show improved vehicle-handling performance.