Engineers use the environment to give simple robotic
grippers more dexterity.
(August 4, 2015) Most
robots on a factory floor are fairly ham-handed: Equipped with large pincers or
claws, they are designed to perform simple maneuvers, such as grabbing an
object, and placing it somewhere else in an assembly line. More complex
movements, such as adjusting the grasp on an object, are still out of reach for
many industrial robots.
Engineers at MIT have now hit upon a way to impart more
dexterity to simple robotic grippers: using the environment as a helping hand.
The team, led by Alberto Rodriguez, an assistant professor of mechanical
engineering, and graduate student Nikhil Chavan-Dafle, has developed a model
that predicts the force with which a robotic gripper needs to push against
various fixtures in the environment in order to adjust its grasp on an object.
For instance, if a robotic gripper aims to pick up a pencil
at its midpoint, but instead grabs hold of the eraser end, it could use the
environment to adjust its grasp. Instead of releasing the pencil and trying
again, Rodriguez’s model enables a robot to loosen its grip slightly, and push
the pencil against a nearby wall, just enough to slide the robot’s gripper
closer to the pencil’s midpoint.
Partnering robots with the environment to improve dexterity
is an approach Rodriguez calls “extrinsic dexterity” — as opposed to the
intrinsic dexterity of, say, the human hand. To adjust one’s grip on a pencil
in a similar fashion, a person, using one hand, could simply spider-crawl her
fingers towards the center of the pencil. But programming such intrinsic
dexterity in a robotic hand is extremely tricky, significantly raising a
robot’s cost.
With Rodriguez’s new approach, existing robots in
manufacturing, medicine, disaster response, and other gripper-based
applications may interact with the environment, in a cost-effective way, to
perform more complex maneuvers.
“Chasing the human hand is still a very valid direction [in
robotics],” Rodriguez says. “But if you cannot afford having a $100,000 hand
that is very complex to use, this [method] brings some dexterity to very simple
grippers.”
Rodriguez and Chavan-Dafle will present a paper detailing
their new approach in September at the International Conference on Intelligent
Robotics and Systems.