Article About the Phantom

From: Lloyd G. Rasmussen (lras@loc.gov)
Date: Tue May 27 1997 - 11:04:49 PDT


You saw it first at the NFB Convention. There is not one word about
blindness in this article. Perhaps that's what it will take to make
this technology affordable.

This is from the web page of EE Times, from CMP Publications.

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                      Breakthrough brings touch to 3-D
                                      
                               By Larry Lange
                                      
   CAMBRIDGE, Mass. -- A breakthrough product called Phantom is spawning
   a firestorm of activity in the next frontier of the 3-D virtual space:
   haptics--or "touch"--technology. Research in a slew of applications,
   from electronic design to automotive and medical systems, could one
   day yield such futuristic scenarios as virtual circuit boards that
   designers can manipulate by hand and surgical simulations that let
   doctors "feel" an organ without making a cut.
   
   The technology to simulate virtual touch is known as "force feedback,"
   and engineers and scientists are finding that applying this tactile
   dimension opens the door to new possibilities. Indeed, continuing
   projects at the Massachusetts Institute of Technology, the Naval
   Research Lab, Mitsubishi, General Electric and Toyota are showing
   marked progress in a variety of application areas.
   
   Centered largely on the Phantom hardware from SensAble Technologies,
   here, tactile computing is also beginning to move out over the
   Internet, thanks to the company's new software release. Other pioneers
   offering PC-based force-feedback systems include Immersion Corp. (San
   Jose, Calif.) and Cybernet Systems Corp. (Ann Arbor, Mich.).
   
   "When you use a computer, you use your sense of sight to perceive
   what's inside and your sense of hearing to hear representations of
   what's inside. But there's been nothing available that lets you
   interact with a sense of touch," said Thomas Massie, co-inventor of
   the Phantom and chief technology officer at SensAble. Until now, that
   is.
   
   Looking a bit like a miniature Luxo lamp with a thimble on the end,
   the Phantom system, running on a fast Pentium processor, allows
   designers to write software that simultaneously processes signals from
   motion sensors on the Phantom's arm and sends instructions back to the
   motors, telling them how much pressure to apply to the thimble. The
   digital relay repeats 1,000 times per second, making the Phantom
   sensitive to the subtlest of hand motions.
   
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   SensAble has coined the term "3-D touch" rather than use the
   scientific-sounding haptics for what Massie sees as the next wave in
   computing. "In the real world, this is how we interact with the
   world--we touch things, we move them around," he said. "We don't point
   a mouse at them. Touch is how we confirm reality."
   
   In agreement is Thomas von Wiegand, a research scientist at MIT's
   Research Lab of Electronics (RLE). His team is working on projects
   that centrally use the Phantom, such as Virtual Environments for
   Training Electronics Troubleshooting. "We are particularly excited at
   the prospect of haptically conveying abstract fields--such as a rise
   in electromagnetic analysis or vector calculus," von Wiegand said.
   
   As an initial demonstration, part of the MIT/RLE team's efforts are
   being directed toward enabling manual interaction with virtual
   electronic circuit boards and components. Dubbed the Electronic
   Troubleshooting Task, the project is a combined initiative with the
   Naval Air Warfare Center/Training Systems Division.
   
   Touch, von Wiegand said, is giving virtual reality a new dimension.
   "Our results enable a more convincing presentation than that obtained
   using the more typical head-mounted display and VR glove-based
   interface." He added that haptics-based technology is well-suited for
   surgical training for procedures mediated by instruments that already
   utilize mechanical linkages, such as in laparoscopic surgery.
   
   That's exactly what Sarah Gibson believes. As a research scientist at
   Mitsubishi Electronics Research Lab (Cambridge), Gibson leads a team
   that's building a simulation system to train surgeons for
   arthroscopic--typically joint-injury--surgery. The system includes a
   computer model of the knee, the Phantom force-feedback device for
   haptic sensing of the virtual model and real-time rendering of the
   knee model.
   
   "Often, what a surgeon feels is just as important as what he or she
   sees during surgery," said Gibson. "Tissues such as healthy brain
   tissue and tumors might be visually indistinguishable, but they feel
   very different. Surgeons also rely heavily on their sense of touch
   when cutting or suturing tissues."
   
   By using haptics and force feedback, the Mitsubishi team is providing
   a virtual sense of touch for surgeons to implement during interaction
   with a computer model--or even while assisting in remote surgery.
   
   General Electric Co., too, has recently begun applying the Phantom in
   medical R&D. At the GE Haptic Volume Visualization and Modeling Lab in
   Schenectady, N.Y., work with MRIs (magnetic resonance imaging) is
   being investigated. "GE has this multimillion-dollar machine and of
   course, MRIs are very expensive," said Massie at SensAble. "After a
   doctor scans a person, he has to take this 3-D data and somehow
   interpret it. But the best he can do right now is to 'slice' the data
   into a two-dimensional plane and then show it on a screen. GE has
   written a program that uses a Phantom and actually allows a user to go
   in and touch this 3-D data. For instance, you can go in and touch a
   tumor."
   
   With the GE system, said Massie, "you can virtually cut away the skin,
   or the skull, and look at the brain in three dimensions. You can feel
   the nasal passages, the ear canal. You can take the lips off the model
   and look at the tongue behind it. Obviously, this makes better use of
   the million-dollar MRI machine, and you are also allowing the doctor
   to make a better diagnosis."
   
   Taking touch one stop further is a haptics team from the Computer
   Science and Physics Labs at the University of North Carolina at Chapel
   Hill, where research scientists have linked a Phantom to an
   atomic-force microscope that can map a strand of DNA. The result is a
   system that lets researchers actually feel each atom.
   
   That breakthrough raises the possibility of using Phantom to gain
   tactile access to generally intangible objects. "If you're touching a
   DNA strand, you can touch an algorithm," said Massie. "We actually
   debug a lot of our own code here at SensAble by touching it. We can
   feel our bugs to figure out what's going on, rather than going
   directly into the code. That's very compelling."
   
   Similarly, the University of Utah is using the Phantom to visualize
   airflow around computer models, in effect simulating aerodynamics.
   
   SensAble sees several opportunities for the application of 3-D touch
   in design engineering, and detailed some of them at the recent Design
   Engineering Conference in Chicago. For example, said Massie, "You
   could imagine going in and feeling temperature gradient right in the
   chip."
   
   The immediate design niche is in CAD, said Massie. "CAD is fine right
   now for very linear types of things, where you need straight lines,
   exact curves and exact dimension." More difficult is "free-form
   design. What's the shape of a mouth? Those things are still done today
   with blue foam and clay; industrial designers are still very much
   craftsmen." Thus, SensAble is working closely with Japan's Toyota
   Corp. on a Phantom-based haptic solution for automobile design.
   
   For its part, Cybernet Systems has offered force-feedback solutions
   for customers such as Ford Motor Co., NASA and joystick manufacturer
   ThrustMaster Inc. since 1988. Last year it received a $1 million
   contract from the U.S. Army to develop a full-body simulator
   synchronized with a visual presentation based on a head-mounted
   display.
   
   As for Immersion, "the excitement over our technology has been simply
   astounding," said chief executive officer Louis Rosenberg. "It is
   overwhelming to be a small startup company with a technology that
   everyone suddenly wants." Though offering a suite of force-feedback
   products for medical applications, the company's "I-Force" technology
   has also found favor in the gaming industry, including a plethora of
   major joystick makers.
   
   Further game applications may arise now that SensAble has released
   software that offers the ability to touch objects over the Internet.
   With the recent debut of WebTouch and the Ghost Software Developer's
   Kit, it's now fairly simple for haptic-happy industries to create
   real-world applications.
   
   Available as a standalone application or as a Netscape Navigator
   plug-in, WebTouch enables a browser to read in Virtual Reality
   Modeling Language (VRML) files. "You don't need a VRML browser," said
   Massie. "People don't have to build any new 3-D models to accommodate
   our tools if they want to touch them--all the work that's been done
   for 15 years of digitizing models carries over."
   
   For all the activity, haptics development is not without its technical
   problems. For example, Mitsubishi's Gibson says SensAble's Phantom has
   an "elegant mechanical design and we have been happy with its
   performance." However, she said, "the current Phantom version can't
   provide torque feedback, something that is needed for medical
   applications."
   
   In addition, "one other shortcoming of the Phantom's motor-driven
   approach is that the sizes of the reflected [feedback] forces are
   limited. If you push only reasonably hard on the Phantom, you can push
   right through the virtual bone model."
   
   MIT's von Wiegand also foresees problems in convincing the public
   about haptics. "Despite the improvements in surgical technique that
   can be attained by interposing a computer between the surgeon's hand
   and his instrument, it may be a while before the public accepts being
   probed or cut by a telerobotic or computer-mediated linkage," he said.
   
   "Even if the system utilizes force feedback, the spectacular
   consequences of a software glitch during such a surgical procedure are
   sure to capture the public's imagination, limiting acceptance."
   Eventually, though, "as with the accepted medical use of lasers, the
   public will embrace the technology as its safety and reliability are
   proven in practice."
   
   Massie said the overwhelming demand for SensAble's technology has
   spawned confusion as to which direction the firm should move in. But
   he retains his enthusiasm for the potential of the basic haptic
   technology it is founded on. "We'd like to see a Phantom on every
   desktop in the world," he said.
   
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-- Lloyd Rasmussen
Senior Staff Engineer, Engineering Section
National Library Service for the Blind and Physically Handicapped
Library of Congress 202-707-0535
(work) lras@loc.gov www.loc.gov/nls/
(home) lras@sprynet.com



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