A general purpose formulation for nonsmooth dynamics including large rotations: Application to the woodpecker toy

The aim of this work is to extend the finite element multibody dynamics approach to problems involving frictional contacts and impacts. Since rigid bodies and joints involve bilateral constraints, it is important to avoid any drift phenomenon. Therefore, the nonsmooth generalized-a method is used, which imposes the constraints both at position and at velocity levels. Its low intrusiveness allows one to reuse an existing library of elements without major modifications. The study of the woodpecker toy dynamics sets up a good example to show the capabilities of the nonsmooth generalized-a within the context of a general finite element framework. This example has already been studied by many authors who generally adopt a model with a minimal set of coordinates and small rotations. We show that using a finite element approach, the equations of motion can be assembled automatically, and large rotations can be easily considered.