Effective Tire Force Vector Control and Maximization Method for Independent-Four-Wheel-Drive Electric Vehicle

Towards the development of electric motorsport, this paper considers an independent-4WD EV with four-wheel-steering (4WS) system to pursue the limit of maneuverability. This paper proposes an effective method of tire force vector control and maximization by controlling slip ratio and tire slip angle. First, a vehicle model of independent-4WD EV with 4WS system is defined. Next, a simulation of the tire force vector control is conducted and shows that the proposed method can maintain tire workload at 1 for arbitrary tire force orientation. Finally, experimental validation is carried out using a real EV. The result suggests the tire force orientation error was within 10 degree and the tire workload kept around 0.8 - 1.0.