Title: Vehicle stability and attitude improvement through the coordinated control of longitudinal, lateral and vertical tyre forces for electric vehicles

Authors: Yugong Luo; Kun Cao; Yong Xiang; Keqiang Li

Addresses: State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China ' State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China ' State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China ' State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China

Abstract: Advanced electric vehicles equipped with independent electric driving/braking, steering and active suspension systems provide potential for optimal vehicle performance by accurate and independent control of each longitudinal, lateral and vertical tyre force. However, the lack of an effective method for the optimisation and control of tyre forces has restricted the development of this research field. In this paper, a novel method for the coordinated control of longitudinal/lateral/vertical tyre forces is proposed by solving a non-convex optimisation problem. A unified objective function that combines the tyre workload and the dynamic ratio of the vertical forces is developed. Thirty-six constraints, including driving demands, electric actuator characteristics and tyre friction limitations, are considered. An optimisation algorithm that combines constrained optimisation and feasible region planning is proposed. Finally, simulations and experiments using a driver simulator are conducted, which demonstrate that the proposed coordinated control method simultaneously improves handling stability and controls vehicle attitude effectively.

Keywords: electric vehicles; longitudinal tyre forces; lateral tyre forces; vertical tyre forces; coordinated control; vehicle stability; vehicle attitude; non-convex optimisation; vehicle control; tyre workload; driving demands; electric actuator characteristics; tyre friction limitations; constrained optimisation; feasible region planning; simulation; handling stability.

DOI: 10.1504/IJVD.2015.073112

International Journal of Vehicle Design, 2015 Vol.69 No.1/2/3/4, pp.25 - 49

Received: 28 Jun 2014
Accepted: 01 Dec 2014

Published online: 20 Nov 2015 *

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