Title: Yaw stability control of a four-independent-wheel drive electric vehicle

Authors: Yan-e Zhao, Jianwu Zhang

Addresses: School of Mechanical Engineering, Institute of Automotive Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, 200240, Shanghai, PRC. ' School of Mechanical Engineering, Institute of Automotive Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, 200240, Shanghai, PRC

Abstract: A yaw stability control system is proposed to improve the handling and stability of a four-independent-wheel drive Electric Vehicle (EV). The control system comprises an Active Front Steering (AFS) controller together with a direct yaw moment controller based on Sliding Mode Control (SMC) and a dynamic force distribution controller based on the optimal Sequential Quadratic Programming Method (SQPM). The function of the control system is to trace the desired yaw rate and meanwhile to keep the sideslip angle of the body Centre of Gravity be minimised. The optimum torque distribution method is applied to adjust the torque of all four wheels. By measuring the vehicle states, the control algorithm determines the level of vehicle stability and intervenes when necessary through individual wheel traction control to provide added stability and handing predictability. The controller system distributes torque and power to each motor to meet the requirements of each wheel. The effectiveness and validation of the proposed control method are evaluated by experiments and simulations. The results manifest that the designed system can assist drivers in controlling the EV|s stability during adverse driving manouevres and enhance its performance.

Keywords: electric vehicles; four-wheel drive; direct yaw moment control; DYC; active front steering; AFS; force distribution control; yaw stability control; vehicle handling; vehicle stability; sliding mode control; vehicle performance.

DOI: 10.1504/IJEHV.2009.027677

International Journal of Electric and Hybrid Vehicles, 2009 Vol.2 No.1, pp.64 - 76

Received: 09 Sep 2008
Accepted: 21 Feb 2009
Published online: 07 Aug 2009 *

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