Title: Pitch reduction and traction enhancement of an EV by real-time brake biasing and in-wheel motor torque control

Authors: Husain Kanchwala; Johan Wideberg

Addresses: Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur-208016, India ' Department of Transportation Engineering, University of Seville, Seville-41092, Spain

Abstract: This paper focuses on pitch control in braking and traction enhancement in acceleration. During braking the vehicle pitches, which greatly determines the ride comfort; on the other hand, during acceleration an optimum value of wheel slip is desired for better traction. In the first part, we control the vehicle pitch of a Fox electric vehicle by real-time brake biasing. We begin with determining side view swings arm centre positions as a function of wheel travel for both front and rear suspensions. Next using these instantaneous centres, vehicle pitch point is determined and the mathematical model for vehicle pitching is developed. Finally, a PD controller is developed which minimises vehicle pitch using brake biasing. In the second part, the motor torques are controlled by maintaining a constant wheel slip at which maximum longitudinal force is generated. The results show significant reduction in vehicle pitch and better tracking of desired velocity profile.

Keywords: electric vehicles; pitch control; brake biasing; torque biasing; in-hub wheel motors; anti-dive; ride comfort; kinematics; compliance; pitch reduction; wheel slip; traction enhancement; motor torque control; vehicle braking; vehicle pitching; mathematical modelling; PD control; controller design.

DOI: 10.1504/IJVSMT.2016.077931

International Journal of Vehicle Systems Modelling and Testing, 2016 Vol.11 No.2, pp.165 - 192

Received: 26 Aug 2015
Accepted: 04 Mar 2016
Published online: 22 Jul 2016 *

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