Mechanics for Robot Hands and Arms
the same in space as on Earth. The astronauts themselves
do need to be firmly attached to a non-movable wall, floor,
or boom so they will not be the objects that move.
Terrestrial Approach to
Gravity Compensation
Most people think of the Iron Man suits from the
movie of the same name or the exoskeleton that Sigourney
Weaver fought with in Alien as the best representatives of
mechanisms people wear over their bodies to augment
their physical capabilities. Most exoskeletons require an
external energy source from a trailing cable to power the
many hefty motors within the suit. Complex actuators and
feedback sensors are fed or feed data to a computer, and
hand controls determine the motions required. These are
complex and expensive robotic machines and are designed
to give the user power beyond what he might have as a
mere human being. Figure 6 shows actor Robert Downey,
Jr. on the set of the Marvel Comics 2008 Iron Man movie
discussing props used in a scene. The complexity shown in
the movie is not far off from what real systems would
require.
Compensating for gravity does not mean adding
superior strength to a human’s lifting capacity. Workers in
automobile assembly lines quite often use overhead cables
to counterbalance a particularly heavy tool that needs to be
maneuvered around a car during assembly, such as a spot-welding head or a frame to pick up and install a windshield
or dashboard. The parts do not need to be heavy to tire a
person from repetitive handling. Sometimes a human just
needs a bit of help to continue lifting or holding an object,
such as in smaller assembly-line operations. A worker might
need a bit of help retrieving parts out of bins right in front
of him (or her) hundreds of times a day or more.
FIGURE 6. Robert Downey, Jr. discusses Iron Man
props on set.
Mechanical Solution to
Overcome Gravity
Many times, movie studios use steel track laid down on
the ground over which a camera dolly is pushed to follow a
moving scene. A handheld camera can do the same job
without the task of laying track. Handheld cameras have
been used for years to
allow a cameraperson
to follow a scene while
walking. This is
especially true when
following the action
might catch a view of
the track on the
ground. The spring-balanced Steadicam has
solved this dilemma. A
fairly affordable
Steadicam “Glidecam Smooth Shooter” is shown in Figure
7 in use with a video camera.
FIGURE 8. Defy Gravity
by Equipois.
SERVO 09.2011 79
