The speed wobble is a phenomenon in nonlinear dynamics that can occur in many vehicles such as bicycles, motorbikes, skateboards and airplanes nose landing gear. The dynamic instability affects the steerable wheels of a vehicle and can lead to the loss of control. While for bikes, motorbikes and airplanes the dynamics and causes of the wobble are well known and the literature fully describes the subject, for the skateboard the literature is very poor and there is no paper which investigates this type of instability.
In order to do that, the skateboard equations of motion were obtained through Lagrange formalism and Lagrange multipliers method was used to solve the non-holonomic constraints. A parametric stability study was carried out on the linearized equations of motion and the influence of different skateboard parameters was investigated.
The main discovery is that the wobble doesn’t strictly depend on skateboard configuration, but the human control characteristics are predominant in the vehicle dynamics.