Fundamental Study on Driving Force Control Method for Independent-Four-Wheel-Drive Electric Vehicle Considering Tire Slip Angle

Electric vehicle (EV) has great advantages in vehicle maneuverability using electric motor. As one of EV's motion control methods, driving force controller with slip ratio limiter has been proposed. In the conventional methods, slip ratio saturation value was fixed so that the controller was only applicable for going on straight. To make it usable for cornering as well, this paper proposed a variable slip ratio saturation method considering tire slip angle. Its effectiveness was verified by simulations and experiments on acceleration cornering close to tire's limit. The result shows a reduction of overall tire slip, and required steering angle was reduced by 20% at most for the same vehicle trajectory.