Most of the time the concept of "robot" is just fingerspelled.
There are many kinds of "robots" but if you are telling a story to
children or discussing a mechanical humanoid type robot then you
could use the "robot" sign.
Sometimes by "robot"
you really mean a "machine." In that case, use the "machine" sign.
MACHINE / engine / factory:
You can learn
American Sign Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars