Traction and Yaw-rate Control of Electric Vehicle with Slip-ratio and Cornering Stiffness Estimation

In traction control systems of vehicles, it is generally required to detect vehicle speed in order to obtain the slip-ratio. However, it is hard to measure vehicle speed directly. In the first part of this paper, novel estimation method of slip-ratio is proposed without detecting the vehicle speed. Based on this estimation, a slip-ratio controller is developed with feedback linearization. In the second part, a novel DYC is proposed with the adaptive observer which can identify the front and rear cornering stiffness independently as well as it can estimate the body side-slip angle. The advantages of proposed methods are verified by simulations and experiments with an electric vehicle which has two in-wheel motors.