On the castor dynamic behavior

In this paper, a model describing the castor three-dimensional dynamic behavior, is presented. A procedure, based on the Udwadia–Kalaba formulation has been implemented to write the castor non-linear motion equations. The model takes into account the flexural and lateral compliance of the castor frame and the phenomena related to the wheel rotation. To prescind from the wheel–road interaction parameters, the hypothesis of no sideslip of the wheel has been adopted but other tire models can be easily implemented. The non-linear system stability is evaluated integrating the motion equations and performing a fitting procedure on the natural steering oscillation.