You're cruising along in a computer space game when an asteroid hits your ship. You see the craft shudder, you lose some points. But your joy-stick doesn't shake with the impact. That's the problem with computer games and virtual reality. You can see it. But you can't really feel it. Not yet.
Ed Colgate, a mechanical engineering professor at Northwestern University in Evanston, Ill., is working to change that. His lab has rigged up a crank linked to a computer. The crank turns easily, until Ed decides to create a virtual wall.
An intrigued guest in his lab, I whip the crank around. Wham! It runs into something very solid. I try again. Same result. There's no getting through this virtual wall. "We can make this wall a lot squishier," Ed says. An assistant presses some buttons on the computer. Now when I turn the crank, it feels like I'm hitting a rubber mat.
All this resistance is simulated. The computer is sending signals to an electric motor attached to the shaft, which mimics what it would feel like to hit a brick wall - or a rubber one.
This technology, called a haptic interface, promises to make virtual reality far more realistic than it is today. The lab's team has already replicated the feel of pushing a button, turning a bolt until it gets tight, and twirling a pendulum. They are also working on three-dimensional movements. Simulating the feel of something would allow a game player to feel the drag of gravity or a crew to drill in a hazardous-spill cleanup before attempting the real thing.
The main purpose of this work is to help NASA. The space agency already spends millions of dollars training its astronauts for weightlessness. They spend long hours in underwater tanks. The problem is that while the astronauts feel weightless, the water slows down their movements, and the tools they practice with fall to the bottom of the tank. So training to use the special tool needed to close the shuttle hatch in an emergency, for example, gets tricky on earth. The Northwestern lab is trying to come up with a way to replicate that feel with virtual reality.
This is harder than it seems. The eye is easily fooled by a computer-generated picture that flashes a mere 60 times a second. But a person can feel changes 400 times a second or more. These speeds force virtual-reality computers to make incredibly rapid calculations. Another challenge is building devices that duplicate the feel of the real world.
While Northwestern is working on making virtual reality seem real for the hand and the arm, Sandia National Laboratories in Livermore, Calif., is doing the same for fingers. Technician Ron Renzi has applied for a patent on a virtual glove. The glove has six tiny magnetically controlled rods at each fingertip. Computers force these plunger-shaped rods to move up and down against each fingertip, mimicking various sensations.
So when a user sweeps his fingers across, say, a block of stucco in virtual reality, the rods go up and down simulating the peaks and valleys of the surface. The lab has also simulated the feel of stone and wood. Such a glove could sell for under $100, the researcher estimates.
Other efforts are under way. A researcher at the Massachusetts Institute of Technology has developed a robot arm with a thimble-shaped device at the end. By putting a finger in the thimble, users can feel anything from rubber balls to keyboards.
Several companies - including Exos Inc. in Woburn, Mass. and Cybernet Systems Corporation in Ann Arbor, Mich. - are working on commercial products for virtual feel.
How long before the technology reaches the rest of us? Just a few years, researchers say. Then those virtual asteroids will - ouch! - give one a jar.
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