Science / Medicine : Don’t Swat That Fly: That’s the Vacuum Cleaner
Imagine flea-sized machines that tell a mechanic what’s wrong with a car or advise when a tune-up is needed.
Or tiny, self-propelled sweepers that scurry into hard-to-reach corners, suck up dirt and dust and return to the vacuum cleaner that released them.
Or a robot the size of a gnat that navigates through the body’s vascular system to correct a heart defect.
Such are the extraordinary but perhaps not impossible visions of engineers crafting tiny building blocks for a revolutionary new technology: micromachines.
In a handful of laboratories, pioneering researchers are turning to the same technology that spawned the microelectronics industry to produce devices that some day may serve as everything from assembly line workhorses to instruments for intricate surgery.
Big Industry Ahead?
“This will be a new industry,” said George A. Hazelrigg of the National Science Foundation. “I think it will be a big one.”
Researchers from UC Berkeley outlined their efforts at a conference on the campus earlier this month.
Scientists are creating gears, turbines and motors so small that 60,000 of them would fit in a single square inch. Because they can in principle be mass-produced on a chip using semiconductor manufacturing technology and material, the microrobots may prove to be cheap as well as useful.
Roger T. Howe of UC Berkeley predicts “a real revolution in the mechanical world.”
But Kaigham Gabriel of AT&T;’s Bell Laboratories cautions, “There is a lot of potential, but there are major problems to overcome before any of our visions are crystallized.”
Roger T. Howe, associate director of the Berkeley Sensor and Actuator Center, suggests the new technology will be important in the automobile industry. In the next few years, for example, hundreds of thousands of automobiles will be equipped with crash sensors to trigger the release of air bags when needed.
Tiny Speed Sensors
The key element of a crash sensor is an accelerometer--a device that can detect a car’s deceleration instantly. Accelerometers smaller than a match head, fabricated on chips along with the associated circuitry, already exist--and their cost is low.
As the tiny gadgets grow cheaper and are commonly installed in automobiles, Howe foresees the day when a car “may be smart enough to tell you when it needs servicing. As the car gets more and more ‘intelligent,’ it may even be able to tell the mechanic what’s wrong with it.”
Micromachines made by a process of etching patterns on silicon chips may also change the way delicate eye, brain or other microsurgery is performed.
For example, microscopic tools on a catheter, inserted through a blood vessel, could enable surgeons to do “closed heart” surgery.
“Some day, we could have some small actuating thing go in and scrape out blocked arteries, maybe eliminating heart attacks,” says Richard Muller of UC Berkeley.
Miniature robots might also be able to take over the tedious and eye-straining job of attaching wires, one-thousandth of an inch thick, that connect a chip’s microelectronic circuits to the pins or electric plugs that mount the chip package to a circuit board.
“We may be wrong in our predictions since the micromachinery business is about where the computer industry was in 1950: at the very beginning,” Hazelrigg said. “And if you told people 25 years ago a computer would be used as a word processor, they’d laugh.”
Like the Computer Revolution
The same technology that transformed computers from lumbering giants into tiny chips that run everything from missile-guidance systems to microwave ovens is being used to shrink mechanical devices to microscopic dimensions.
At Bell Labs, Gabriel and William Trimmer have used silicon chip processing techniques to make air-driven turbines and working gears with teeth less than one-fifth the thickness of a human hair.
Berkeley scientists have made the first microscopic movable mechanical parts, including cranks, gears, springs and joints, and are working to produce the first silicon micromotor.
To make complete micromachines, engineers will need to take another step--combining computer circuitry with the micromotors and mechanical elements.
The machines will also depend on sensors to feed them information about the outside world. Engineers have already made miniature sensors that can detect pressure, chemical vapors, changes in speed and other factors.
There is also the question of whether the tiny components will wear out over time. The Berkeley researchers are exploring new materials and properties that may eventually prove superior to anything currently used.
As in any infant field, “We have a lot of unexplored territory,” Muller said.
