Page 29 - Concise Encyclopedia of Robotics

Assembly Robot
Various landmarks can be used as artificial stimuli. It is not necessary
to have wires or magnets embedded in the floor, as is the case with the
AGV. A robot might be programmed to follow the wall on its right-hand
(or left-hand) side until it reaches its destination, like finding its way out
of a maze. The lamps in a hallway ceiling can be followed by light and direc-
tion sensors. The edge of a roadway can be followed by visually checking
the difference in brightness between the road surface and the shoulder.
Another way to provide guidance is to use a beacon. This can be
an infrared (IR) or visible beam, or a set of ultrasound sources. With
ultrasound, the robot can measure the difference in propagation time
from different sources to find its position in an open space, if there are
no obstructions.
There are many ways that objects can be marked for identification.
One method is bar coding, which is used for pricing and product identi-
fication in retail stores.Another is a passive transponder, of the type attached
to merchandise to prevent shoplifting.
See also AUTOMATED GUIDED VEHICLE, BAR CODING, BEACON, EDGE DETECTION, and PASSIVE
TRANSPONDER.
ASIMOV’S THREE LAWS
In one of his early science-fiction stories, the prolific writer Isaac Asimov
first mentioned the word “robotics,” along with three fundamental rules
that all robots had to obey. The rules, now called Asimov’s three laws, are
as follows.
• A robot must not injure, or allow the injury of, any human being.
• A robot must obey all orders from humans, except orders that
would contradict the First Law.
• A robot must protect itself, except when to do so would contradict
the First Law or the Second Law.
Although these rules were first coined in the 1940s,they are still considered
good standards for robotic behavior.
ASSEMBLY ROBOT
An assembly robot is any robot that assembles products, such as cars,
home appliances, or electronic equipment. Some assembly robots work
alone; most are used in automated integrated manufacturing systems
(AIMS), doing repetitive work at high speed and for long periods of time.
Many assembly robots take the form of robot arms. The type of
joint arrangement depends on the task that the robot must perform. Joint
arrangements are named according to the type of coordinate system they
follow. The complexity of motion in an assembly robot is expressed in
terms of the number of degrees of freedom.

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