Impact of Toe and Thrust Angle Misalignment on Roll Behaviour of a Heavy Commercial Road Vehicle

Abstract

<div class="section abstract"><div class="htmlview paragraph">Heavy Commercial Road Vehicles (HCRVs) may be more susceptible to rollover incidents due to their higher centre of gravity position than passenger vehicles, and rollover is one of the significant causes of HCRV accidents. Therefore, variation in vehicle roll behaviour becomes crucial to the safety of an HCRV. Toe misalignment is a commonly observed phenomenon in HCRVs, and studying its impact on roll behaviour is important. In this study, the impact of the symmetric toe and thrust misalignment on the roll behaviour of an HCRV is analysed using IPG TruckMaker^®, a vehicle dynamics simulation software. A ramp steer manoeuvre was used for the simulations, and the toe misalignment on a wheel was chosen from the range [-0.21°, 0.21°]. Variation in roll behaviour was quantified using the steering wheel angle at which one-wheel lift-off (OWL) occurred (<i>SWA_L</i>). Additionally, an analytical model was formulated to predict OWL and the model predictions were compared with the results from IPG TruckMaker^®. The data synthesised from IPG TruckMaker^® showed that OWL occurred at the same lateral acceleration (0.3<i>g</i>) but at a lower or higher steering angle, depending on the magnitude and configuration of misalignment. Front axle thrust misalignment had the highest impact, leading to a maximum of 3.4% variation in <i>SWA_L</i>, followed by a 2.6% variation for rear axle thrust misalignment and a 2.1% variation for symmetric toe misalignment. The formulated analytical model predicted OWL-Axle (axle on which wheel lift-off occurs first) and the corresponding lateral acceleration (0.32<i>g</i>), which agreed well with those from IPG TruckMaker^®. The study identified conditions under which symmetric toe and thrust misalignment impact the roll stability of an HCRV.</div></div>