Screw bondgraph contact dynamics

Abstract

This paper presents an elegant contact dynamics model in screw bondgraph form. It can model the contact between any two objects of finite curvature. It does so by defining a Gauss frame on the surfaces of both objects in the points that are closest to each other. Then it describes how the Gauss frames move as the objects move relative to each other. This is called the contact kinematics. The contact kinematics detect when two objects touch, then describe how they roll and slide over and along each other, and then detect when they get loose again. With the contact kinematics a dynamic screw bondgraph model is built. This dynamics model is verified in two simulations. The first simulation shows two objects of nontrivial curvature, eggs, rolling over each other. The second shows a robotic hand manipulating an object.