[info] eurekalert: magnetic levitation-based haptic interface

[Alejandro Dubrovsky]

(
http://www.eurekalert.org/pub_releases/2008-03/cmu-mlg030308.php
)

Contact: Anne Watzman
aw16 at andrew.cmu.edu
412-268-3830
Carnegie Mellon University
Magnetic levitation gives computer users sense of touch
NSF makes Carnegie Mellon invention available to more researchers

PITTSBURGH— Computers, long used as tools to design and manipulate
three-dimensional objects, may soon provide people with a way to sense
the texture of those objects or feel how they fit together, thanks to a
haptic, or touch-based, interface developed at Carnegie Mellon
University.

Unlike most other haptic interfaces that rely on motors and mechanical
linkages to provide some sense of touch or force feedback, the device
developed by Ralph Hollis, research professor in Carnegie Mellon’s
Robotics Institute, 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 while
using an interface that responds rapidly to movements.

“We believe this device provides the most realistic sense of touch of
any haptic interface in the world today,” said Hollis, whose research
group built a working version of the device in 1997. With the help of a
$300,000 National Science Foundation grant, however, he and his
colleagues have improved its performance, enhanced its ergonomics and
lowered its cost. The grant also enabled them to build 10 copies, six of
which are being distributed to haptic researchers across the U.S. and
Canada.

“We have gone from the prototype to a much more advanced system that
other researchers can use,” Hollis said. Putting the instrument in the
hands of other researchers is critical in a young, developing field such
as haptic technology, he emphasized. Though haptic interfaces have uses
in engineering design, entertainment, assembly, remote operation of
robots, and in medical and dental training, their full potential has yet
to be explored. That’s particularly the case for magnetic levitation
haptic interfaces because so few have been available for use by
researchers, he added.

“This is an affordable device that’s also practical,” said Hollis, who
has started a spinoff company to build additional devices. “Now other
people can have this technology, and this represents technology transfer
in the very real sense.”

Six devices will be delivered to researchers at Harvard, Stanford,
Purdue and Cornell, as well as to the universities of Utah and British
Columbia. All are members of the Magnetic Levitation Haptic Consortium,
an international group dedicated to fostering increased use of this
technology.

Hong Tan, associate professor of electrical and computer engineering at
Purdue University and a consortium member, studies human perception of
fine surface textures — work that requires simulation resolution at the
micron level. “This is beyond the capability of most commercially
available haptic devices, but the maglev device developed by Dr. Hollis
will make it possible for us to continue this research,” she said.

“The field of haptic research and development is expanding rapidly,”
said Rob Conway, project manager in Carnegie Mellon’s Center for
Technology Transfer. “Carnegie Mellon’s research opens new possibilities
by joining the world of haptic feedback with a comfortable magnetic
levitation interface. The magnetic levitation decouples the interface
device from the mechanical world, eliminating friction, backlash, jump,
sticking and other interfering effects, so that the user feels only the
artificial environment in complete accuracy down to the micro scale.”

The system eliminates the bulky links, cables and general mechanical
complexity of other haptic devices on the market today in favor of a
single lightweight moving part that floats on magnetic fields.

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.

A user moves the handle much like a computer mouse, but in three
dimensions with six degrees of freedom — up/down, side to side,
back/forth, yaw, pitch and roll. 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 this virtual object encounters other virtual surfaces and
objects, corresponding signals are transmitted to the flotor’s
electrical coils, resulting in haptic feedback to the user. Hollis and
his colleagues will demonstrate the new maglev haptic interfaces at the
IEEE 16th Symposium on Haptic Interfaces for Virtual Environments and
Teleoperator Systems, March 13-14 in Reno, Nevada.

###

For details on the Haptic Consortium, see
www.msl.ri.cmu.edu/projects/haptic_consortium/

About Carnegie Mellon: Carnegie Mellon is a private research university
with a distinctive mix of programs in engineering, computer science,
robotics, business, public policy, fine arts and the humanities. More
than 10,000 undergraduate and graduate students receive an education
characterized by its focus on creating and implementing solutions for
real problems, interdisciplinary collaboration, and innovation. A small
student-to-faculty ratio provides an opportunity for close interaction
between students and professors. While technology is pervasive on its
144-acre Pittsburgh campus, Carnegie Mellon is also distinctive among
leading research universities for the world-renowned programs in its
College of Fine Arts. A global university, Carnegie Mellon has campuses
in Silicon Valley, Calif., and Qatar, and programs in Asia, Australia
and Europe. For more, see www.cmu.edu.