Bifurcation of lane change on highway for large bus

Abstract

In this study, a new method is proposed for analysing the non-linear dynamics and stability in lane changes on highways by large buses. Unlike most of the literature associated with a simulated linear dynamic model for large buses, a verified 4DOF mechanical model with non-linear tire based on vehicle test is used in the lane-change simulation, including sinusoidal steering and steer returning. According to Jacobian matrix eigenvalues of the vehicle model, bifurcations of steady steering, sinusoidal steering and steer returning with disturbance on highways are investigated using a numerical method. The numerical simulation results reveal that Hopf bifurcations are identified in steady and sinusoidal steering conditions, which translates into an oscillatory behaviour leading to instability. Various equilibrium forms of stability are found, as well as saddle and Hopf bifurcations with disturbance ζ variety. The derived knowledge of the bifurcations set is hugely important to fully understand the actual dynamic motions of vehicles when lane changing on an even surface. It is a valuable reference for safety design of large buses to improve the traffic safety of driver–vehicle–road closed-loop system.