GEERHEAD
Here, the Aqua robot and a diver are working
together in a pool. The robot obeys image-based commands delivered by hand in front of
its camera. This control technology was
developed because the robot cannot receive
radio-based commands underwater.
These image-based communications are called
RoboChat. All underwater communications must
be acoustic or visual. Acoustics are typically
too slow. Some of the commands the diver
gives the robot are stop, go, follow the diver,
surface, etc. The technology also enables the
diver to give the robot numerical inputs. The
robot can be programmed while under water
using these images.
follow a diver or the contours of a reef,” explains Dudek. “It
learns patterns associated with a particular diver it wants to
follow, and looks for those patterns and follows them.”
These patterns include combinations of colors, motions,
and textures.
This is called target recognition. The technology uses a
filter that analyzes each picture the robot takes. If it is
tracking a face, it will have been trained on what two eyes
look like and it will search for those. The technology uses
hundreds of filters. This is called ensemble tracking because
it uses an ensemble of filters.
In the first stage of training the robot’s tracking system,
researchers show the robot an image of something they
want it to follow. In the second stage, some of the robot’s
systems train the other systems. The robot’s interworkings
constantly adapt to what one of its systems knows is a
correctly identified target.
In the research at York University, the robot applies
trinocular sensors which use two cameras together to see
how far apart objects are under water. One camera looks
ahead following a diver, while another looks at the terrain
below, mapping it out.
Thanks to the computers and cameras, the robot takes
better images including videos (watch the lobster video in
the resources). When the robot surfaces, researchers may
want to know right away if it saw anything of significance.
The robot may have taken three hours of video, but with its
new technology it can identify the 25 most interesting
images very quickly.
The problem with selecting the things that are
interesting from all the images is that the technology has to
model things that people would find interesting. So, the
robot needs to be able to identify those. In the model,
some things are interesting because they are new, and
12 SERVO 07.2010
some are interesting because they are unlike
any previous images.
The Aqua robot works in tandem with
stationary sensors in the water. There is a
separate project dedicated to deploying these
sensors to collect data. An Aqua robot can
swim to a sensor, pick up the data, and
retrieve it.
The Aqua robot also has legs — a new set that are fully
amphibious, so it can walk and swim, and do both very
well. Photos are currently unavailable as this technology is
still a bit under wraps. Having the Aqua robot swim and
then walk directly onto shore when done opens up a lot of
possible uses. These include military applications where the
bot can stay on the beach and then go into the water to
de-mine the surf zone. The robot could also walk into the
water, swim and collect data, crawl back out of the water,
and walk into a designated area and uplink the data. Or, it
can follow a diver into the water.
Final Thought
The RHex-based Aqua robot is blazing a new trail in
water research robots. SV
Resources
Aqua robot sees lobster (video)
www.youtube.com/watch?v=FCOZFwzMiU8
Aqua robot walks on shore (video)
www.youtube.com/watch?v=pXXikLMXhtY
Aqua robot scales angled
sandy terrain (video)
www.youtube.com/watch?v=aiDV06DIqE8
Aqua robot transitions from water to shore
with new legs (video)
www.youtube.com/watch?v=lpkXopUHKg8
RHex Robot Platform
www.rhex.web.tr