New Haptic Interface for Computers Gives Users the Sense of Touch

Carnegie Mellon researchers have developed a new type of haptic interface for computers that enables users to virtually reach into their screens and physically interact with simulated objects and environments.

"Haptic" refers to something sensed by active touch.

The interface, which employs magnetic levitation, is unique because it enables people to not only touch these objects, but to manipulate them in three dimensions as well. The new system also eliminates the bulky links, cables and mechanisms of current haptic interfaces in favor of a single, lightweight moving part, which floats on magnetic fields.

The system has a bowl-shaped floating element containing six levitation coils surrounded by strong, permanent magnets. A protruding handle attached to the bowl is grasped by the computer user, enabling interaction with solid, three-dimensional models graphically depicted on the computer screen. The system is housed in a desktop-high cabinet.

"With a magnetic levitation haptic interface, you can reach into a simulated environment and feel the force and torque of simulated objects," said Ralph Hollis, a principal research scientist in the Robotics Institute.

"Early in their development, computers used to be just text. Then came graphics, 3D graphics and speech, involving more and more of a user's senses. Of the last three senses left - smell, taste and touch - the latter will likely be the most useful," he said.

It has taken Hollis and doctoral student Peter Berkelman five years to develop the haptic interface. They believe that future applications of the technology will be in computer-augmented design, medical training, entertainment, flight simulation and the interactive control of remote robots.

Hollis and Roberta Klatzky, head of the Psychology Department, have received a $600,000 grant from the National Science Foundation to study the psychophysical aspects of magnetic levitation devices relative to how people perceive virtual and real worlds.

"Over the past several years, my colleagues and I have worked on the interface between engineering and behavioral science, assessing the value and potential of various devices for human users," Klatzky said.

"We can take a device like the haptic interface and give people tasks that test its capabilities. In this instance, we'll give people the task of manipulating remote objects, for example, placing a peg in a hole where these objects are depicted on a screen, or in a real environment but manipulated by a robot. We will compare these remote conditions to direct manipulation," she said.

For more information on Carnegie Mellon's magnetic levitation haptic interface, visit the Web at

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