The Mouse That Soared

Floating 'mouse' reduces mechanical interference for a real feel of computer images.

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So far, humans have sensed computing environments mostly through sight and sound. Now, researchers are working to bestow yet a third of the five human senses upon the ubiquitous machines: touch. A new device called a "maglev" eliminates the bulky links, cables and general mechanical complexity of computer "touch" devices in favor of a single lightweight moving part that floats on magnetic fields. With such a gizmo, you could feel, say, the rocks and crevices on the surface of Mars just by scrolling over an image of the planet on your computer screen.

A user operates the maglev much like a computer mouse, except it has a handle that moves in three dimensions and in different directions—up and down, side to side, back and forth, and yaw, pitch and roll. This moves a virtual "feeler" on the computer display, which bumps into or rolls over other virtual surfaces and objects and sends signals back to the user, which he or she experiences through the hand.

Scientists and engineers have been working on such "haptic," or touch-based devices for decades, but Ralph Hollis, a research professor in Carnegie Mellon's Robotics Institute, says the one he developed is better.

"We believe this device provides the most realistic sense of touch of any haptic interface in the world today," said Hollis, whose research group first built a working version of the device10 years ago. Since then, Hollis and his colleagues have improved its performance, enhanced its ergonomics and lowered its cost so other researchers can use it to advance the field.

Unlike most other haptic interfaces that rely on motors and mechanical linkages to provide some sense of touch, Hollis’ device uses magnetic levitation and a single moving part to give users a highly realistic experience. Users can perceive textures, feel hard contacts and notice even slight changes in position.

At the heart of the maglev haptic interface is a bowl-shaped device called a flotor that is embedded with six coils of wire. Electric current flowing through the coils interacts with powerful permanent magnets underneath, causing the flotor to levitate. A control handle is attached to the flotor.

Optical sensors measure the position and orientation of the flotor, and this information is used to control the position and orientation of a virtual object on the computer display. As that virtual object encounters other virtual surfaces and objects, corresponding signals are transmitted to the flotor's electrical coils and fed back to the user.

So, haptic devices are different from mice and joysticks in that they allow information to flow in both directions—from the user to the computer and back, often in the form of force or resistance felt by the hand. By unlinking the interface device from the mechanical world, the maglev eliminates, backlash, jump, sticking and other interference so the user feels only the artificial environment in complete accuracy down to the micro scale.

Hollis and his colleagues will demonstrate the new maglev haptic interfaces at a symposium March 13-14, in Reno, Nev.

This work was supported by the National Science Foundation.

—By Leslie Fink/NSF

This report is provided by the National Science Foundation, an independent federal agency that supports fundamental research and education across all fields of science and engineering, in partnership with U.S. News and World Report.