Dynamic simulation and virtual control of a deformable fingertip

Abstract

An efficient computational model for the dynamics of a deformable robot fingertip is presented. The dynamic model is based on a discretization of the fingertip's volume into a lattice of masses locally interconnected by damped springs. The lattice's parameters are adjusted in correspondence with bulk properties of the fingertip's deformable material (rubber). In the task studied, the fingertip moves toward a rigid flat surface, contacts it, and presses against it. This motion is commanded by an external feedback controller which communicates with the dynamic model through a virtual control interface: The controller applies forces and torques to the dynamic model and the dynamic model responds in real-time with position/velocity/force feedback information. In this fashion, the controller interacts with the fingertip's model in the same way it would interact with the actual physical system. This type of paradigm is envisioned as a prototyping/testing tool in the design of control systems for deformable objects as well as for applications involving the haptic (i.e., sensorially realistic) interaction between a human and a virtual (deformable) object. Graphical snapshots of a real time simulation of the task under study are presented which reveal the physical and computational plausibility of the model.