Abstract: Two types of shimmy problems in automotive engineering, wheel shimmy and vehicle body shimmy, as well as their behaviors and generation mechanism, are discussed in this paper. A review of their research history and significant achievements at home and abroad are presented as the main part of this paper. The shimmy phenomenon is essentially a very intricate nonlinear dynamics behavior, and many questions in theory and in practice still have to be answered. Both wheel shimmy and vehicle body shimmy are self-excited oscillations of nonlinear systems, and they can be attributed to the positive work generated by the forces at the contact patch between the tires and ground. The continuation of the shimmy behavior is just maintained by the input energy to the system. Meanwhile, the wheel subsystem with elastic tires, the steering subsystem and the suspension subsystem are the three key sources where influences on the shimmy behavior come from. Seeing that the shimmy problems are still challenges in vehicle dynamics and might change for the rapid developing new energy automobiles, the existing problems related to shimmy and their future research perspective are presented as well.

Key words: lateral stability, vehicle body shimmy, vehicle dynamics, wheel shimmy