Spin: camber and turning

摘要

The paper clarifies some important issues connected with wheel slip due to spin. The spin velocity is defined as the component of the rotational velocity of a rolling body normal to the contacting surface. For a tyre we distinguish two possible components of spin: camber and turning. Different from a homogeneous rolling body, the tyre with its peculiar structure may give quantitatively different responses to each of these components. When comparing the steady-state responses with side-slip and with pure turn slip (path curvature) of some analytical tyre models, it turns out that the aligning torque stiffness is equal to the turn-slip side-force stiffness. This reciprocity may be explained by energy considerations. A tyre model featuring spin-induced side-slip loses this reciprocity. This seems to be verified by tyre side-slip and turn-slip tests. Experimental methods and results are discussed. Some peculiar features and the importance of spin in vehicle dynamics are discussed and demonstrated in several applications of the short-wavelength intermediate-frequency tyre (SWIFT) model.