Analytical Methods in Vehicle Dynamics
Yaw stability of a passenger vehicle with respect to road disturbances
Project group
Peter Folkow, Associate Professor, Division of Dynamics
Mathias Lidberg, Associate Professor, Division of Vehicle Engineering and Autonomous Systems
Background
The research group in vehicle dynamics is studying active safety systems to improve safety and stability for passenger and heavy vehicles. Much of the development in this area concerns control technology with new actuator systems such as active steering and differentials. However, there are still a need for the development of the automotive chassis and tire. There are many interesting problems within modern vehicle dynamics that are directly related to advanced analytical mechanics. Consequently, there are needs to combine knowledge from both vehicle dynamics and analytical mechanics [3]. In this project, the latter field is covered by the Division of Dynamics which has competencewithin rigid body mechanics, using both analytical and numerical methods.
Project Proposal
Tire characteristics are of crucial importance for the dynamic behavior of the road vehicle. It is well known that the steady state slope of the tire side force vs slip angle near the origin is the determining factor for basic linear handling and stability. The stability of the motion at large lateral acceleration is in a similar way determined by the local slope of the same tire characteristic and other factors such as wheel camber angle [4]. Recently, tire models capturing the influence of tire pressure and wheel camber have been developed [1]. However, very little is known about the influence of these tire properties on the stability of road vehicles. It is therefore proposed to study the yaw stability of a passenger vehicle with respect to road disturbances including more detailed tire characteristics [2]. It is expected that the stability analysis is challenging and requires approaches beyond linear stability theory e.g. Lyapunov stability theory.
Implementation
The two students will work together in the same office at Chalmers Johanneberg. All four (the two students and the two supervisors) will have one meeting every second week. At least one of the supervisors will meet the students once a week.
Project plan:
Introduction (1 week)
Literature Review ( 1 week)
Modeling and Stability Analysis(4 - 6 weeks)
Simulation Study (4 - 6 weeks)
Thesis Writing (4 weeks)
Presentation (2 weeks)
Anticipated research results and synergy effects
This project will be carried out as a cooperation between the Divisions of Dynamics and Vehicle engineering and Autonomous systems.
It is anticipated that this research will result in new insight in the vehicle dynamics field, based on rigorous treatment of the tire-road interaction and its influence on vehicle stability. This kind of projects is quite rare, as much research within vehicle engineeringis based on simplified assumptions that sometimes are questionable for detailed analysis. It is likely that the result of the thesis can be published at least at a scientific conference.
The proposed work is important for the vehicle dynamics research projects performed at Chalmers. These projects involve similar aspects to the work proposed but does not allow for the rigorous treatment aimed for here. The results are also expected to be possible to apply by the vehicle industry e.g. Volvo, SAAB in their development process. This will hopefully increase the chances of attracting industry funding for further activities in this field.
References
1. I. J.M. Besselink, A. J.C. Schmeitz, H. B. Pacejka, An improved Magic Formula/Swift tyre model that can handle inflation pressure change, VehicleSystem Dynamics 2010.
2. W.Liang, J.Medanic, R.Ruhl, Analytical dynamic tire model,VehicleSystem Dynamics, 2008.
3. B. Andersson, P. Gillberg, High Speed Braking Stability, MSc Thesis, Chalmers University of Technology 2013,
4. CamberTire,