Methods to Control Wheel Locks and Wheel Spins for Electric Vehicles with the Structure Having Independently Driven Front and Rear Wheels

Abstract

Wheel locks and spins occur easily when braking pedal and accelerator operations are performed while running on low friction coefficient roads such as snowy or frozen roads. In order to control these phenomena which are related to vehicle safety, an electric vehicle (EV) with the structure that can control the front and rear wheels independently is effective. This type vehicle has been proposed and developed by the authors as the next generation ECO vehicle. This paper describes methods which are suitable for the developed EV to control wheel locks and wheel spins. In these methods, the driving and braking torques are properly distributed to the front and rear wheels according to running road states while slip ratios of the front and rear wheels are controlled in consideration of the load movement. Effectiveness of the methods is verified through experiments using a prototype EV with the above structure