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Thomas Bernd Kabutz and Schalk Els
Most forces on a ground vehicle go through the tyre contact patch. Because the tyre interfaces with the road surface, it is not possible to directly measure the contact patch. This presents a significant challenge in assessing soil characteristics. Predictions of the tread deformation allow estimates of total soil deformations. This can be used to determine elastic and plastic deformation of soil under moving vehicles, giving insight into soil parameters. Soil deformations and parameters are beneficial for vehicle control as well as evaluating the environmental impact. Previous studies utilized digital image correlation techniques to measure tyre deformation on the inner surface of the tyre. This paper investigates the feasibility of developing a measurement system that uses deformations on the inner surface of a tyre to predict the deformation on the outside. The proposed method involves offsetting the inner surface along its normal directions by the tread thickness to obtain the outer surface of the tyre. A 2D proof of concept was developed, showing the ability to predict tread deformation based on inner surface measurements. Reasonable accuracy was achieved, thus confirming the feasibility of predicting tyre tread deformations from inner surface measurements by a geometry offset. The identified errors are deemed acceptable for the given problem, with the errors due to the simplification of the problem proving significantly smaller than measurement-induced errors. A full 3D model was consequently developed to predict tread deformation over the full contact patch region. The findings pave the way for the development of a real-time system to predict soil volume displacement, providing crucial insights for vehicle control and environmental impacts in offroad scenarios.
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