Implementation of a Semi-active Auxiliary Axle for Lateral Stability of Articulated Heavy Vehicles at Extreme Loss of Control Limit

Abstract

Articulated heavy vehicles (AHVs) play a vital role in the economy of freight transport. Lateral stability control of AHVs during the immediate vicinity to loss of control (LOC) is a significant issue that has not been effectively addressed in the literature. This paper presents a novel approach to the lateral stability control of tractor semi-trailers under conditions leading to LOC. An active auxiliary axle is proposed to prevent trailer swing and snaking during severe lane change maneuvers. A linear 3-DOF model was developed to represent the effectiveness of the active auxiliary axle and tire cornering stiffness in yaw-rate control to provide an analytical basis. Nonlinear modeling of the axle and vehicle system was performed in TruckSIM. A Fuzzy Logic Controller (FLC) was developed to identify the required rate (magnitude per unit time) of actuation force, and a PID controller was introduced to regulate the magnitude of actuation force at the axle-wheel interface. Co-simulation was performed in MATLAB/SIMULINK in combination with TruckSIM. To simulate an LOC on a dry road with a coefficient of friction of 0.85, a double lane change (DLC) maneuver at 90 km/h was conducted. This resulted in a combined state of relative roll-over and trailer swing, facilitating the evaluation of the semi-active auxiliary axle's performance in regaining stability and eliminating transient overshoots in the vehicle combination's lateral response. Yaw rate rearward amplification was effectively controlled, and articulation angle oscillations were significantly diminished. This approach suggests a systematically minimal yet practicable retrofit to the trailer, contributing to a remarkable improvement in the traffic safety of AHVs.