JHU Eng 2002-6 (undergrad invention: tool for disabled)

[Dennis O'Shea]

THE JOHNS HOPKINS UNIVERSITY
OFFICE OF NEWS AND INFORMATION
3003 N. Charles Street, Suite 100
Baltimore, Maryland 21218-3843
Phone: (410) 516-7160 / Fax (410) 516-5251
May 30, 2002

MEDIA CONTACT: Phil Sneiderman
(410) 516-7907
prs@jhu.edu

FOR IMMEDIATE RELEASE

STUDENTS INVENT VOICE-ACTIVATED GRASPING TOOL FOR DISABLED MAN

Using two motors, speech-recognition software and an exo-skeleton inspired 
by science fiction, three Johns Hopkins University undergraduates have 
designed and built a muscle enhancement device that will help a disabled 
man grasp and lift a cup, a book and other household items. By uttering 
commands such as "open" and "raise," the man will receive mechanical help 
in moving his fingers and bending his elbow. The motorized plastic shell 
will fit over the right arm of the man, who has an extremely rare 
degenerative muscle disorder called inclusion body myositis

This device, which could be adapted for other people with disabilities, was 
developed during two semesters by students in the Department of Mechanical 
Engineering's Senior Design Project course. The project originated last 
summer when the man with the muscle disease sought help from Volunteers for 
Medical Engineering, a nonprofit Baltimore group that uses technology to 
assist people with disabilities. The client, who asked that his name not be 
disclosed, explained that his nerves were intact, meaning that he could 
control the placement of his fingers around an object. But progressive 
muscle deterioration left him unable to grasp and lift even small objects.

To help him, the VME sponsored a project in the Johns Hopkins course. The 
task of designing and building the device went to a team consisting of 
three senior students: Jonathan Hofeller, 21, a mechanical engineering 
major from Needham, Mass.; Christina Peace, 21, a biomedical engineering 
major from Baltimore; and Nathaniel Young, 22, a biomedical engineering 
major from Dayton, Ohio. The students researched prosthetic limbs and, 
taking a cue from props featured in the film "Aliens," they designed a 
plastic exo-skeleton that could slide over the client's right hand and arm. 
To help move his fingers and elbow, the students tested and rejected 
systems using electromagnets and air pressure systems. They finally settled 
on two small but powerful stepper motors. These could move the fingers and 
elbow in small, slow increments, allowing the client to clasp a cup firmly 
without crushing it. In addition, these motors did not require continuous 
electrical current to stay in position, which preserves battery power. The 
students linked the motors to a series of cables and springs to enable the 
device to move the man's arm into position and help his fingers grasp and 
release.

The students opted for voice recognition software as an easy way for the 
disabled man to control the grasping device. After the software is trained 
to the client's voice, the man will first say "arm" or "hand" to take 
command of one of the two motors. The elbow motor will then respond to 
"raise," "down" or "stop." The hand motor will respond to "open," close" 
and "stop." The device is hard-wired to a control box that contains a 
miniature computer and two programs that turn the voice commands into 
signals that tell the motors how to operate the bending and grasping 
motions. The unit is powered by a rechargeable 12-volt lead-acid battery 
commonly used for remote-control model boats and airplanes. The control box 
fits inside a small pack the man can carry on his waist, making the 
grasping the device fully portable. 	

"The students did a wonderful job," said Jan Hoffberger, executive director 
of Volunteers for Medical Engineering. "They came up with a very creative 
design for the device. They purposely set it up to move very slowly, so 
that at any time in the grasping and lifting process, our client can tell 
it to stop. We believe he will find it very helpful."

The students had to work within a budget of $10,000; they ended up spending 
about $8,000 on the device. Designing and building it helped the 
undergraduates to understand some of the challenges that working engineers 
face. "In a textbook, there is always one right answer," said Young. "In 
this project there were many different ways we could go, but once we were 
committed we had to go in that direction." His teammate, Hofeller, said, 
"The project involved a lot of trial and error, but it was fun to apply 
what we've been learning." The third team member, Peace, added, "When 
you're working out a problem in an engineering book, the conditions are 
ideal. In this project, the conditions were not perfect, but we still got 
the job done."

The grip enhancing device was one of 11 Johns Hopkins projects completed 
this year by undergraduates in the Senior Design Project course. The class 
is taught by Andrew F. Conn, a Johns Hopkins graduate with more than 30 
years of experience in public and private research and development. Each 
team of two or three students, working within budgets of up to $10,000, had 
to design a device, purchase or fabricate the parts, and assemble the final 
product. Corporations, government agencies and nonprofit groups provided 
the assignments and funding. The course is traditionally a well-received 
hands-on engineering experience for Johns Hopkins undergraduates.

                                                                      ###

Color images of the device and the students available; contact Phil 
Sneiderman or see http://www.jhu.edu/news_info/news/home02/may02/grasp.html 
and http://www.jhu.edu/news_info/news/home02/may02/grasp2.html

Related Links:
Johns Hopkins Department of Mechanical Engineering: http://www.me.jhu.edu
Volunteers for Medical Engineering: http://www.toad.net/~vme