Title: Development of an optimal control system for longitudinal and lateral stability of an individual eight-wheel-drive electric vehicle

Authors: Ming-Chun Liu; Cheng-Ning Zhang

Addresses: National Engineering Lab for Electric Vehicles, School of Mechanical Engineering, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian, Beijing 100081, China ' National Engineering Lab for Electric Vehicles, School of Mechanical Engineering, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian, Beijing 100081, China; Beijing Co-innovation Center for Electric Vehicles, Beijing, China

Abstract: This paper presents an optimal torque allocation control method for an individual eight-wheel-drive electric vehicle to improve longitudinal and lateral stability. The proposed optimal controller is designed as a hierarchical structure with an upper level controller and a lower level controller. The upper controller including human driver model is developed using sliding mode control algorithm, which takes longitudinal velocity, side slip angle and yaw rate as control variables. The lower controller is developed using optimal control algorithm, which optimally allocates the tractive/braking torque to eight in-wheel motors and mechanical brake system independently. Numerical simulation studies, including driver-vehicle-controller in-loop and open-loop simulations, are conducted to investigate the performance of the proposed controller. The simulation results show that the proposed controller significantly improves vehicle longitudinal and lateral stability.

Keywords: eight-wheel-drive electric vehicles; torque allocation control; sliding mode control; SMC; optimal control; longitudinal stability; lateral stability; vehicle stability; controller design; longitudinal velocity; side slip angle; yaw rate; tractive torque; braking torque; numerical simulation.

DOI: 10.1504/IJVD.2015.073117

International Journal of Vehicle Design, 2015 Vol.69 No.1/2/3/4, pp.132 - 150

Received: 14 Nov 2014
Accepted: 04 Mar 2015
Published online: 20 Nov 2015 *

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