Title: Active control of a truck full-trailer's rearward amplification

Authors: Moustafa El-Gindy, Scott Lewis, Nezih Mrad

Addresses: Pennsylvania Transportation Institute, The Pennsylvania State University, 201 Research Building, University Park, Pa. 16802, USA. ' Penn State Applied Research Laboratory, Autonomous Control and Intelligent Systems Division, PO Box 30, State College, PA 16804, USA. ' Structures, Materials and Propulsion Laboratory, Institute for Aerospace Research, National Research Council of Canada

Abstract: This paper presents the results of examining the influence of tyres| uncertainties (represented by the variation of the cornering stiffness) on the actively controlled rearward amplification (RWA) of six-axle truck/full-trailer. In this preliminary study, a four degrees of freedom yaw/plane model has been developed and used. The RWA is defined as the ratio of the peak lateral acceleration at the rearmost trailer|s centre of gravity (cg) to that at the cg of the lead unit during lane-change manoeuvre. The vehicle under consideration is a 6-axle truck/full-trailer, which usually exhibits a high level of rearward amplification ratio leading to rollover during obstacle avoidance manoeuvres. In this study, the effect of the active control torque applied to the dolly is examined by using the optimal linear quadratic regulator (LQR) and sliding mode controller approaches. Unlike the LQR algorithm, the sliding model controller is designed to account for uncertainties (tyres cornering stiffness variation in this study). The control performance index criteria are determined for the vehicle based on an acceptable RWA target value. For active yaw control at the dolly cg, the optimal controller is found to be most sensitive to the dolly|s tyres, cornering stiffness variations and least sensitive to steering axle from the RWA ratio point of view. It is also found that the controller was determined to be most sensitive to the steering axle parameter variations for the path following case. Simulation results indicate that the rearward amplification ratio can be reduced without significant change of the uncontrolled vehicle trajectory when active yaw torque is applied to the dolly. The sliding mode controller is found to be more effective in improving the dynamic performance in terms of reducing the rearward amplification during severe lane-change manoeuvres. This improves the vehicle roll stability, particularly when parameter uncertainties such as tyre cornering stiffness are present.

Keywords: heavy vehicles; linear quadratic regulator; truck full- trailer rearward amplification; tyre cornering stiffness.

DOI: 10.1504/IJHVS.1998.054618

International Journal of Heavy Vehicle Systems, 1998 Vol.5 No.3/4, pp.277 - 299

Published online: 18 Jun 2013 *

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