Self-excited Torsional Vibrations of the Driven Wheels in a High-Performance Car

During heavy acceleration launch maneuvers of high-performance cars, a high amplitude vibration can arise due to disturbances such as road surface irregularities. This vibration manifests itself as an oscillation of the wheel center with respect to the vehicle’s chassis coupled with a torsional vibration involving the driveline, the latter being so violent it can damage and crack the driving axles. This study presents evidence of the problem, and assesses the results obtained from stability analysis of a minimal model. The leading parameters controlling the onset and amplitudes of this anomalous vibration are identified and can be classified as a type of “axle tramp,” a self-excited oscillation occurring on driven axles. The influence of each governing parameter of the model is analyzed, in particular those characterizing the tyre forces and the suspension mechanism, with the aim of finding possible passive control strategies.