Page 435 - Sensing, Intelligence, Motion : How Robots and Humans Move in an Unstructured World

410 SENSITIVE SKIN—DESIGNING AN ALL-SENSITIVE ROBOT ARM MANIPULATOR

move as close as possible to the shown trajectory while avoiding collisions
with previously unknown obstacles.
3. Tests with a fully autonomous operation. The robot is expected to interact
with the human (who shares workspace with the robot) by moving next to
him or her. Whether or not the human partner is watching the robot, the
robot is expected to be “out of the way” of the human. One variation of
this test is when the arm “follows” the human, by keeping at some distance
from him/her while avoiding collisions.

When entertaining such experiments, one is reminded of the Isaak Asimov’s
three laws of robotics (from his short story I, Robot, 1950). In tests 3 above,
since the robots used were heavy industrial manipulators, Asimov’s first law (“A
robot may not injure a human being.. .”) suddenly took on a literal meaning.
Manufacturer technical manuals of industrial robot arm manipulators prohibits,
in no uncertain terms, humans from sharing space with such robots. Industrial
robots are large and heavy and fast—they can hurt. Factory work cells with
robots are often equipped with automatic means for stopping the robot if the rule
is somehow neglected (e.g., this can be a laser or wire sensor guarding the robot
perimeter, doors that are automatically locked when the robot is turned on, etc.).
In the described experiments, however, the whole point of the sensitive skin
and collision-avoidance software is that no such protection is necessary anymore.
A whole-sensitive robot is expected to never hurt a human: It should gently move
aside or back or around the human. And, it should do it no matter whether the
human noticed the robot. Aside from Asimov’s dramatic formulations, common
sense says that without such ability the robot simply cannot be used as a, say,
astronaut assistant. The assistant’s function may be to hand the astronaut tools
and to take them back for storage, or, say, help the astronaut move and rotate
bulky objects. In this team the astronaut must share space with the robot, and he
or she cannot afford to always be aware of the robot presence. No less important
is of course the robot’s own safety; the skin should protect it from hurting itself
by banging into surrounding objects. (Recall Asimov’s third law: “A robot must
protect its own existence.. .”).
This author and his students, and later people who did not know much about
robotics, have spent much time next to the robot, testing its “gentleness” provided
by its sensitive skin and its intelligence. Nothing bad ever happened. This, of
course, is not surprising: Multiple protective layers often appear in engineering
systems. If worse comes to worse, the system should stop (we never came to this
point in our experiments).
The pictures in Figures 8.9 to 8.12 show a few frames from videos taken in
6
the laboratory during some of those tests. The pictures in Figure 8.9 correspond
to the test setting 1 above: The robot was instructed to start from some position
on the left side of the scene and finish at some position on the right. Along the

6 A note to the reader: videos that supplied pictures for Figures 8.9 to 8.11 can be seen in full on
the web, http://aaaprod.gsfc.nasa.gov/Project/public html-NASA/LaRue-Lumelsty.htm.