Experimental study on dynamic characteristics of rolling agricultural tire (identification of lug excitation force)

Abstract

When agricultural machines are operated on pavements, the vibration and noise caused by interaction between the tire lugs and the road surface are inevitable. Therefore, it is important to investigate the lug excitation force occurring on a rolling agricultural tire in order to clarify the vibration generation mechanism. In our previous study, it was confirmed that the dynamic behaviour of a rolling tire is influenced by the vibration characteristics of the tire. Further, only the rigid modes among the natural modes could affect the rolling tire behaviour. Therefore, we modelled the tire as a circular rigid ring supported on an elastic foundation with a contact model. This rigid ring model can represent those modes of vibration of the tire in which the tire ring moves as a rigid body and the equations of motion for translational motion are derived. In order to identify the lug excitation force, the shaft displacement and the shaft force during rolling motion are measured by rolling test. The tire ring displacement, supposed to be the vibration due to lug excitation frequency, is identified from the measured data using least squares method. The shaft forces predicted by the calculation using the identified parameters show good agreement with measured shaft forces. So, the validity of this identification method are confirmed. Finally, the lug excitation forces are identified.