World - Bucknell University

RESEARCH & TEACHING
Making a Better Bot
’RAY BUCKNELL
6 BUCKNELL WORLD • September 2006
The Plan for Bucknell calls for
building bridges to the world. Mechanical engineering
professor Keith Buffinton is doing just
that by involving students in real-world research.
Buffinton oversees the Pulse Width Control (PWC)
Project with his colleague, University of Washington associate
professor Martin Berg. Funded by the National Science
Foundation, the project is involved with developing precise
control of robotic devices.
As demands increase for finer and finer scale movements,
friction presents a serious challenge to robotics.
“When you’re trying to do really small maneuvers, even
small amounts of friction can cause you not to reach your
goal,” Buffinton says.
Countless variables affect friction, making it difficult
to predict how much force is needed to move a robot arm
precisely to the spot where it has a job to do.
Pulse Width Control offers a way to deal with the
uncertainty of friction. Rather than pushing a robot arm
along until it reaches its destination, a series of pulses are
given to the robot, like giving a coffee mug a push across a
table and then waiting to see where it comes to rest. If the
mug — or robot arm — doesn’t end up where you want it,
then another push is given. The key is for each push to be
just strong enough to overcome friction.
The PWC project is an outgrowth of work that
Buffinton and Berg did on a large robot used by the Boeing
Company in Seattle to construct airplanes. The real-world
application gave them an opportunity to test their ideas.
“It was a way for us to demonstrate that the idea, the
concept, the theory really worked with a real robot,”
Buffinton says. “Now we’re trying to take the same idea
and expand it for different types of applications, for different
types of robots, and to make it more flexible.”
One way that Pulse Width Control could be more flexible
is to design a system that can respond to changes in the
• Tulu Bayar, assistant professor
of art, was awarded an international
Artist-in-Residency position at Camac
Centre D’Art in Marnay-sur-Seine,
France, and spent the spring there
working on a new project. Bayar, a
photographer and multimedia artist,
completed her new work, “Addicted,”
a performance-based multimedia
installation, and presented it at Camac
to an audience from Paris, Bordeaux,
and the Champagne-Ardenne region
in France, as well as to a panel of
international curators.
• Buoyed by a school-record
eight Patriot League championships
in 2005–06, Bucknell captured the
Patriot League Presidents’ Cup for the
12th time in the 16-year history of
the conference. The Bison compiled
115.75 points in the Cup standings,
the most ever for Bucknell and the
third most in league history. Army,
the only other institution to have
won the Presidents’ Cup, was runnerup
with 108 points. In addition to the
league’s all-sports trophy for both
men and women, Bucknell won the
women’s trophy for the 12th time.
The Bison women set records for
points earned and margin of victory.
From left to right, Katie Hoffman ’08, Keith Buffinton, Christian Hubicki ’07, and
Chris Shake ’09.
factors that affect a robot’s performance, such as temperature
fluctuations, or picking up an object.
“We’re developing an adaptive controller, so rather
than having to know all the system parameters precisely,
we have a controller which learns the parameters as it does
maneuvers,” Buffinton says.
Students are integral to the PWC project. In his research,
Christian Hubicki ’07 is working on a version of PWC
called tabular control, which involves using a table to
calculate the values to send to the controller. His research
experience at Bucknell will be invaluable preparation for
his goal of studying robotics in graduate school.
Not only do Buffinton’s undergraduate researchers gain
hands-on research experience, but they also publish papers,
travel to conferences, and meet with Berg’s group twice a
year to discuss their work. Hubicki will travel to Heidelberg
with Buffinton in September to present their research.
The PWC Project also benefits from another “Bucknell
bridge” helped by Scott Alfieri ’94, a partner in the consulting
firm Accenture. In 2003, Alfieri started the Accenture
Technology Discovery Undergraduate Research Grant,
(ATDURG) which enables the 65 Bucknell graduates working
at Accenture to contribute to a matching fund that
directly supports undergraduate research at Bucknell. This
summer, Katie Hoffman ’08 received ATDURG support to
work with Buffinton. “This is a nice way to give back and
fund something that’s material and that students can really
dig their teeth into,” says Alfieri. — Barbara Maynard ’88
• Paul Humphreys ’28 not only
reached a milestone birthday in June
when he turned 100, but he also was
admitted into Phi Beta Kappa. Bucknell
did not have a chapter until 1942, and
he was invited to join then. However,
Pearl Harbor had just been attacked,
and he was unable to think about an
honor society when the world was at
war. His son, Richard Humphreys ’62,
found the invitation letter tucked
away and thought that a membership
into Phi Beta Kappa would make a
wonderful birthday surprise for his
father, and it indeed was — 78 years
after his graduation and 64 years after
the original invitation.