Well established vehicle models and simulation methods are more and more important in nowadays technical evolution. With the rise of learning-based techniques in self driving car research, simulated environments have rising importance.
With the advances in vehicle dynamic softwares in the recent years, building models, and defining test cases getting easier, but finding the proper parameters for these vehicle models is usually very labor intensive. One of the most basic parameters of a vehicle model is its center of gravity height.
This paper investigates different center of gravity height estimation methods. The goal is to get a picture about their accuracy, field of suitable application, required time, necessary technical equipment, financial and human resources. We also investigate the possible sources of inaccuracy, and developed procedures to avoid, or at least minimize those.
Three types of estimation methods were examined. First, a static case, when the car is not moving, and the center of gravity height is calculated from the changes in the tire normal force during lifting one axle. These measurements can be carried out in a properly equipped workshop.
Then two dynamic methods are described, where the car is moving and the center of gravity height is calculated from the logged data of an advanced measurement system, that makes possible to log tire normal forces, lateral or longitudinal accelerations, damper potentiometer displacements. These measurements require a lot of sensors in the chassis and suspension and a data logging system. Both calculation methods are based on the dynamic load transfer during accelerations. First, the changes in the measured tire normal forces during longitudinal or lateral accelerations were used to determine center of gravity height, and in the second dynamic case, the tire normal forces were not measured but estimated from damper potentiometers.
The results confirm the widespread use of a well performed “lifted axle method”, as turns out to be an efficient choice, without the need for costly sensors and tools. A good comparison is also established about these estimation methods, and detailed procedures for each are developed to avoid mistakes during the different measurements.
Comparison of Center of Gravity Height Estimation Methods
Lect.Notes Mechanical Engineering
Vehicle and Automotive Engineering ; 2020 ; Miskolc, Hungary November 25, 2020 - November 26, 2020
2020-10-20
9 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Comparison of Center of Gravity Height Estimation Methods
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