A constraint-based god-object method for haptic display

TLDR

Haptic display applies forces to a user to simulate touching real objects, relying on a system comprising an electro‑mechanical interface, a mathematical object model, and a real‑time rendering algorithm that computes model‑based forces. The paper introduces a new haptic rendering algorithm to generate convincing interaction forces for rigid polyhedra. The method constructs a virtual “god‑object” model of the haptic interface that conforms to the environment, allowing the interface to be servoed to this model in real time. The algorithm is extensible to other functional descriptions and establishes a foundation for rendering not only shape but also surface properties such as friction and compliance.

Abstract

Haptic display is the process of applying forces to a human "observer" giving the sensation of touching and interacting with real physical objects. Touch is unique among the senses because it allows simultaneous exploration and manipulation of an environment. A haptic display system has three main components. The first is the haptic interface, or display device, generally some type of electro-mechanical system able to exert controllable forces on the user with one or more degrees of freedom. The second is the object model-a mathematical representation of the object containing its shape and other properties related to the way it feels. The third component, the haptic rendering algorithm, joins the first two components to compute, in real time, the model-based forces to give the user the sensation of touching the simulated objects. This paper focuses on a new haptic rendering algorithm for generating convincing interaction forces for objects modeled as rigid polyhedra. We create a virtual model of the haptic interface, called the god-object, which conforms to the virtual environment. The haptic interface can then be servo-ed to this virtual model. This algorithm is extensible to other functional descriptions and lays the groundwork for displaying not only shape information, but surface properties such as friction and compliance.