Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
As the development of highways, it is quite normal for buses running in a speed around
100km/h. When buses are running in a high speed, they may suffer from the influence of side
wind disturbances at anytime. Sometimes, it may result in traffic accidents. Therefore, the
study of bus stability under side wind disturbances becomes more and more important. Due to
restrictions of real tests, computer simulation can be used to study this subject. The bus side
wind response character is reflected through the driver’s manoeuvre , so open-loop analysis is
hard to give a comprehensive evaluation of the side wind stability of the bus. Therefore,
closed-loop analysis is studied in this thesis.
An ADAMS bus model and a side wind force model are developed in this thesis, along with
two driver models, the PID control model and the preview curvature model. The driver
models are built in Simulink and co-simulation between ADAMS/View and Simulink is
The results of co-simulation show that the two driver models can both control the bus from
deviating from the desired course under side wind disturbances. The PID control model is
simple and shows a very good control effect. The maximum lateral displacement of the bus by
PID control model is just 0.0205m under maximum side wind load 1000N and 2500Nm when
preview time is 1.2s, while it is 0.0702m by preview curvature model, however, it is difficult
to determine the coefficients Kd, Kp, and Ki in the PID controller. The preview curvature
model also shows a good control effect in terms of the maximum lateral displacement and
yaw angle of the bus. Comparing these two models, the PID control model is more sensitive
to deviations, with quicker response and larger steering input.
The bus model system is stable under side wind disturbances. Through driver ’s proper steering manoeuvre, the bus is well controlled. The closed-loop analysis is a good method to study the bus stability under side wind disturbances.
2013. , 48 p.