University of Utah researchers have developed a motor that is the width of seven strands of hair. It's the next step in the race between the United States and Japan to develop the smallest computer, which one day could be used in travels into the human body.

The "wobble motor," now humming along at the university's Center for Engineering Design, has potential applications in medicine, surgery, engineering and the kitchen, said Dr. Steve Jacobsen, center director.Uses of microelectromechanical systems, or MEMS, have the potential to offer what the design center's team calls a "revolution in some areas." That includes allowing surgeons to probe in areas current devices are to big to probe.

"We are working at the limits of science and engineering," he said. "These are machines you can't manufacture by touching and can't fix. They require enormous predesign."

A wobble, as Jacobsen calls it, is a tiny rod turning inside a shaft. The rod slightly wobbles as it rolls around inside. Rolling reduces friction and solves the problem of lubricating something that is 560 microns wide. A hair strand is 80 microns wide.

And Jacobsen said tests are being conducted on a second wobble that is 200 microns wide - or less than the thickness of four strands of hair. Mass-produced MEMS could function in what Jacobsen described as "massive computer memories, cheaper than dirt."

Such motors potentially can lead to a new class of mechanical, optical, fluid, thermal and chemical machines, "which exhibit otherwise impossible improvements in performance, reliability, and economy."

Scientific instruments, measuring devices, sensors, manipulation of biological materials, realistic artificial limbs, display terminals, unique filters and manufacturing devices are just a few others.

Tiny motors on the tip of a catheter, for example, could enter the human body to examine, measure and perform minifunctions now out of reach to surgeons, perhaps even dealing eventually with individual cells, said Jacobsen.

Japan has made developing MEMS its top research and development target in the race to make the smallest machine possible.

The tiny motor has the gears and gizmos in all motors and uses electrostatic forces rather than magnetic forces that most larger motors use. The motor is driven by applying voltages to its walls.

The rotation produces high torque, which could be harnessed to equally small saws, knives, claws or similar devices to grip, cut, twist or do other work.

Advanced work in the field deals with trying to make such microscopic machines run smoothly for more than brief periods. The motor shows very little wear "and no signs of quitting," according to the design center team.

Most of the work on MEMS has involved technology used to make computer microcircuit chips, which has produced tiny, flat, two-dimensional motors. The U.'s wobble motor is a leap forward to a fully functional three-dimensional system.

The U. is one of six institutions researching MEMS. The project has been financed by a grant from the Defense Advanced Research Proj-ects Agency and by the Systems Development Foundation.

Work on MEMS began six years ago at the U. as an outgrowth of two other projects in Jacobsen's laboratory: the Utah artificial arm, which uses electrical signals in an amputee's remaining muscles to move the complex arm; and the Utah/MIT dextrous hand, a four-fingered robotic limb built to mimic the human hand.