02-03-2011, 12:54 PM
presented by:
Neha Jha
D. Naga sivanath
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ABSTRACT
“HAPTICS”-- a technology that adds the sense of touch to virtual environment .Haptic interfaces allow the user to feel as well as to see virtual objects on a computer, and so we can give an illusion of touching surfaces, shaping virtual clay or moving objects around.
The sensation of touch is the brain’s most effective learning mechanism --more effective than seeing or hearing—which is why the new technology holds so much promise as a teaching tool.
Haptic technology is like exploring the virtual world with a stick. If you push the stick into a virtual balloon push back .The computer communicates sensations through a haptic interface –a stick, scalpel, racket or pen that is connected to a force-exerting motors.
With this technology we can now sit down at a computer terminal and touch objects that exist only in the "mind" of the computer.By using special input/output devices (joysticks, data gloves, or other devices), users can receive feedback from computer applications in the form of felt sensations in the hand or other parts of the body. In combination with a visual display, haptics technology can be used to train people for tasks requiring hand-eye coordination, such as surgery and space ship maneuvers.
In this paper we explicate how sensors and actuators are used for tracking the position and movement of the haptic device moved by the operator. We mention the different types of force rendering algorithms. Then, we move on to a few applications of Haptic Technology. Finally we conclude by mentioning a few future developments.
Introduction
What is Haptics?
Haptics refers to sensing and manipulation through touch. The word comes from the Greek ‘haptesthai’, meaning ‘to touch’.
The history of the haptic interface dates back to the 1950s, when a master-slave system was proposed by Goertz (1952). Haptic interfaces were established out of the field of tele- operation, which was then employed in the remote manipulation of radioactive materials. The ultimate goal of the tele-operation system was "transparency". That is, an user interacting with the master device in a master-slave pair should not be able to distinguish between using the master controller and manipulating the actual tool itself. Early haptic interface systems were therefore developed purely for telerobotic applications.
Computing contact-response forces:
Humans perceive contact with real objects through sensors (mechanoreceptors) located in their skin, joints, tendons, and muscles. We make a simple distinction between the information these two types of sensors can acquire.
1.Tactile information refers to the information acquired through sensors in the skin with particular reference to the spatial distribution of pressure, or more generally, tractions, across the contact area.
To handle flexible materials like fabric and paper, we sense the pressure variation across the fingertip. Tactile sensing is also the basis of complex perceptual tasks like medical palpation, where physicians locate hidden anatomical structures and evaluate tissue properties using their hands.
2.Kinesthetic information refers to the information acquired through the sensors in the joints. Interaction forces are normally perceived through a combination of these two.
To provide a haptic simulation experience, systems are designed to recreate the contact forces a user would perceive when touching a real object.