Robot Manipulators
operate on 240 VDC. Main
controls, an underwater
telephone (to the surface
support vessel), and
emergency systems operate
at 24 VDC. The Atlantis fleet
also has a larger, 64
passenger sub with a 160
ton displacement.
With so much of the
sub’s control systems similar
to mobile robot technology,
we both felt that the
addition of a pair of remote
manipulator arms could
easily be interfaced with the
sub’s control systems. These
subs are more like an ROV
that carries passengers than
a larger military sub as they
have multiple thrusters to
move in three axes and
rotation, plus they travel at
slow speeds.
FIGURE 2. Space Shuttle Canadarm.
Robot Arms in Hostile or
Inaccessible Environments
Deepwater Horizon
disaster. At an ambient
pressure of over 2,200
pounds per square inch at
the depth of the blowout,
typical manned diving
operations were out of the
question. To be useful in
this difficult environment
(gushing oil from a broken
well head and blowout
preventer), ROVs must
have more capabilities than
just lighting and a TV
camera. Dual multi-axis
arms with a selection of oil
well specific claws are
needed to manipulate
various switches, valves,
and debris, and deposit
‘junk shot’ into the
wellhead blowout preventer.
Operating under the sea can
be extremely hazardous, but
the oceans are not the only hostile place for robots (and
humans).
Robot Manipulators in Space
After talking with Brian, I got to thinking about robot
manipulators as opposed to single industrial robot arms.
People generally think of robot arms as being in the
manufacturing arena, typically painting or welding cars.
Industrial robots are rarely thought of as an extension of a
human’s arm and hand as they perform repetitive,
programmed motions in a factory atmosphere. They are
mainly envisioned as relieving humans of tedious, repetitive,
boring, or dangerous work.
On the other hand, robot manipulators are usually
thought of as extensions for a person’s arms and hands
and are typically teleoperated. Quite often they operate in
pairs. The TV news coverage of the recent Gulf oil spill has
shown ROVs with claws attached to rotating wrist joints,
turning knobs on valves 5,000 feet down. An operator on
the surface was instructing the ROV’s arms and claws to
perform tasks beyond the capability of a human diver. In
contrast, the area in front of the Atlantis IX tourist sub was
not particularly hostile at 125 feet, but was still well beyond
the reach of the crew or the passengers. Sometimes it is
this desire to handle or collect something that justifies the
use of a remote manipulator.
Underwater Remotely
Operated Vehicles
For those of you who may have read the piece, the
July SERVO contained a great article by Dave Prochnow
on the ROVs deployed in the Gulf to assist in the
78 SERVO 09.2010
One of the most famous robot manipulators in use
today is the RMS or Remote Manipulator System used on
the Space Shuttle (Figure 2). Back in 1985 when I was with
Rockwell working on the NASA Space Station Project, I had
the privilege of having astronaut Judith Resnik give me a
short training session on the RMS simulator at NASA JSC.
Handling multi-hundred million dollar payloads and even
astronauts on the RMS’ end-effector requires a reliable fail-safe and functional manipulator system. I later had to
determine the robot manipulator system requirements for
the Space Station which were similar, yet different from the
shuttle’s system.
These days, adding remote robot manipulators is fairly
easy. However, the particular environment of the
applications mentioned above can dramatically increase the
complexity and expense required to design and build
robotic manipulators. Going back about 65 years, one of
the first applications for remote robot manipulators (or
teleoperators) was in the early days of the Manhattan
Project to produce the atomic bombs used in WWII. Figure
3 shows a newer version of the same type of mechanical
master/slave remote manipulators that were used to
assemble radioactive bomb parts in the mid ‘40s.
Mechanical linkages transferred the operator’s motions
directly to the claw and hand within the hot cell behind the
radiation-proof glass window. Nowadays, robot
manipulators have entered nuclear reactors to examine and
repair radioactive parts, delicately grasping and
