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WHAT IS A ROBOT The term robot comes from the
Czechoslovakian wordfor "forced labor," invented by Karel
Capek. Karel Capek used robots in his plays and had them
look and behave like people. Today, the word "robot" is
harder to define because of new designs and technology. The
third edition of Websters's New International Dictionary
defines a robot as "a machine in the form of a human being
that performs the mechanical functions of a human being."
However, today's robot makers are not interested in giving
their creations human forms. Most industrial robots look
like lobsters or oversized grasshoppers. Around 1981, the
members of the Robot Institute of America, held a meeting
to develop a definition of an industrial robot. Finally
after long debate, they came up with the definition: "A
reprogrammable, multifunctional manipulator designed to
move material, parts, tools or specialized devices, through
variable programmable motions, for the performance of a
variety of tasks." The key wor ds in their definition are
"reprogrammable" and "multifunctional." By "reprogrammable"
they mean that if a robot gets a new assignment, it will
need new instructions, but its basic structure will not
change (except maybe a new mechanical hand). By
"multifunctional" they mean a robot is the mechanical
counter part of a computer that can handle various problems
without any major hardware modifications. The only thing
that changes when a robot is reassigned is its program of
instructions. In modern robots, programmable
microprocessors control all the robot's movements and
actions. Robots can be taught by using a teaching mode. An
operator moves the robot's hand through all of the desired
motions manually with his own hand. When the robot is
activated, it will repeat those same motions over and over
again. Most robots are equipped with one hand and one arm
of several articulated joints. Some of these joints swivel
in smooth arcs mimicking the behavior of the human
shoulder, wrist, and elbow. Other robots move in straight
lines similar to a crane. Robots rarely have a pair of
arms, and are usually stationary. If a robot moves that is
all it does. Examples are delivery robots rolling down
halls delivering mail or supplies. The hands and arms of
early robots were pneumatically powered (air pressure) or
hydraulically powered (fluid pressure). Flexible tubes
carried the pressurized substances to the joints. Now,
electric motors located at the joint give the robot greater
precision and control, but slow down its movements. All
robot manufacturers dream of joints with human-like
tendons. Most robots are blind and are insensitive to their
surroundings. Some have sensors triggered by light,
pressure, or heat that can create a crude picture of what
is happening. ROBOTIC ARMS There are four types of robot
arms that are used today. Degrees of freedom are the axes
around the arm in which it is free to move. The area a
robot arm can reach is its work envelope. Rectangular arms
are sometimes called "Cartesian" because the arm's axes can
be described by using the X, Y, and Z coordinate system
developed by Descartes. Descartes is a famous French
philosopher, scientist, and mathematician. If a pen were
attached to the arm, it would draw a rectangle which would
be its work envelope. Imagine a graph where X would be side
to side, and Y would be in and out on the graph. Up and
down would be Z which runs through the graph and describes
depth. Z also adds the third dimension. A cylindrical arm
also has three degrees of freedom, but it moves linearly
only along the Y and Z axes. Its third degree of freedom is
the rotation at its base around the two axes. The work
envelope is in the shape of a cylinder. The spherical arm
replaces up and down movements along the two axes with a
rocking motion of the arm. The spherical arm's work
envelope is a partial sphere which has various length
radii. The last and most used design is the jointed-arm.
The arm has a trunk, shoulder, upper arm, forearm, and
wrist. All joints on the arm can rotate, creating six
degrees of freedom. Three are the X, Y, and Z axes. The
other three are pitch, yaw, and roll. Pitch is when you
move your wrist up and down. Yaw is when you move your hand
left and right. Rotate your entire forearm as if you are
drilling a hole. Your arm would rotate around an axis that
goes through the center of your wristbone. This motion is
called roll. What a robot does is stated in its program.
The program tells a microprocessor what to do. The
microprocessor sends signals to joint boards, which in
turn, send signals to a motor. Then the motor moves the
joint the way the program wants it to. Robots can be
programmed by a computer. An operator enters the work
movements into a computer which tells the robot what to do.
Robots can also be "taught" what to do by having its arm
moved. The operator moves the robot's arm with his own arm
through all the movements. The robot preforms the movements
over and over again. ROBOTS IN INDUSTRY In factories today,
industrial robots perform such tasks as welding, machine
loading and unloading, material handling, spray finishing,
assembly, and machine applications. In nuclear power plants
and other facilities where radiation is hazardous to
humans, robotic arms that are partly machine and human
controlled are used for maintenance, repair, and waste
removal. Similar arms on diving vehicles facilitate
undersea salvage and exploration by navies and offshore oil
industry. WELDING Industrial robots can perform two kinds
of welding operations - spot and arc welding. For spot
welding, two metal sheets are welded by laying one sheet on
top of the other and fusing them with an electric gun at
several points. This is a difficult and unpleasant task for
humans because the welding gun is heavy. Also, assembly
lines only allow a short time to move the gun, and welds
can be placed inconsistently or missed. The parts move on a
conveyor belt and as they pass by, the robot welds them.
The robots remember the position of each weld that is to be
made, and can recall other programs when a new material
appears on the line. In arc welding, metal sheets are
pressed together. Then a thin tungsten wire at the tip of
and electrode is brought close to the surface. Current is
passed through the electrode, creating a spark. The
resulting heat, as much as 6,500 degrees Fahrenheit, melts
the sheets together. Robots are used instead of humans
because of the heat and flying sparks. Also, the robot must
hold the electrode at the same height while welding. This
is hard for a human to do hour after hour. MATERIAL
HANDLING Material handling is the second largest industrial
robot application. A common material handling task is
palletizing parts as they come off a conveyor or
depalletizing parts in order to put them on a conveyor.
Pallets are platforms on which items are transported or
stored. The robot must know if a pallet is filled,
half-filled, or empty. Manufacturers use a bar code like
the ones in supermarkets to tell the robot about the
pallet. Also, some robots have two- dimensional vision that
can recognize the pallet. The program tells the robot to
place the parts in different positions. In depalletizing,
the program tells the robot where to reach for and object
and how to grab it with the correct force. Robots are now
used in Hackettstown, New Jersey. They are used to pack
M&M's and then weigh the package to see if the right amount
has been packaged. The robots the place the packages in a
box. MACHINE LOADING AND UNLOADING Machine loading and
unloading robots pick up and transfer parts to and from
machines. The die-casting industry uses robots to remove
parts from die-casting machines. The die-casting process
forms parts by pouring molten metals in molds which are
cooled later. The working environment is unpleasant for
humans because of the heat. Preparing molds is tiring and
boring because the steps are repeated over and over again.
Robots are well suited for this work. SPRAY FINISHING Spray
finishing includes the application of paint, enamel,
polyurethane, and other protective materials. Human workers
must hold the gun a certain distance and angle from the
surface. Also, he must move the gun continuously to prevent
dripping. The painter uses his own judgements regarding a
good finish. Because of this, products are never
identically finished. The spray finishing environment is
one of the most noxious for humans to work in. Fumes from
solvents are toxic and sometimes carcinogenic. There is a
hazard of fire since finishes are flammable, and noise from
air discharge can damage hearing. In the automotive
industry, robots are use to paint cars, but cannot paint
all of it. Operators must finish the job after the robots
have done what they can. The risk of fire demands the
hydraulic robots rather than the electric driven robots.
Since robots move more smoothly than humans, the paint coat
will be more consistent. Also, robots can be programmed to
switch colors. Spray finishing robots cut costs because
they require less light, reduce fresh-air requirements,
reduce exhaust, and lesson energy costs. Since robots can
operated in isolated areas, fewer particles stick to coated
surfaces as they dry. The isolated environment also means
no ventilation or noise elimination is necessary. ASSEMBLY
AND INSPECTION Robots can bolt or screw pieces together
depending on the job needed. The assembly lines move fast,
so robots are well suited for the job. The robots move fast
and take only one or two seconds to fit pieces together.
Inspection robots fit pieces into a mold to see if they fit
correctly. If the piece doesn't fit the robot rejects or
signals a warning. Robots can rotate pieces to see if they
fit and can change angles. Some advanced robots scan the
pieces as they go by on a conveyor belt. The robot then
checks the piece's measurements to the correct
measurements. This technique is very fast and usually
accurate. Humans aren't really interested in this job.
Humans would take longer to fit the pieces into the mold
because they are not sure which way to turn the piece.
Also, humans can't scan pieces and check the measurements
slave manipulators are robotic arms that humans can control
with joy sticks as well as computers. They are use in
hazardous land, sea, and space environments. The nuclear
industry handles radioactive fuel and wastes with these
devices. The mining industry uses them for waster disposal.
Sea salvage operations would be impossible to be carried
out without these arms. Even the Space Shuttle use an arm
that helps the astronauts launch satellites. Three robotic
manipulators are used to maintain the linear accelerator,
or "atom smasher", at the Los Alamos Meson Physic Facility
in New Mexico. When protons are accelerated, strong
radioactivity occurs. Even if the machine is off, radiation
is still high and hazardous to humans. Workers use the
manipulators to maintain the target area. The arms hang
over the area from a large hydraulic system. The operators,
which are sitting behind a protective wall, move the
controller which moves the arm. The arm has bilateral force
sensing which allows the arm to have collisions with
objects, and yet continue to work. The arm absorbs the
shock the same way a human hand does when catching a ball.
With these manipulators, workers can do almost all of the
things people can do but without risking the effects of
radiation. Soldering, electrical wiring, welding, and
handling materials are some of the tasks achieved. In
deep-sea activities, the hazard is not the object being
retrieved, but depth itself. Humans can withstand depths up
to 300 feet. Depths after that can be dangerous and unsafe
because of pressure. A device called a "wasp" was developed
and tested. It is a cross between a diving suit and a
submarine with two robotic arms. The pilot in the suit can
walk on the floor at depths up to 2,000 feet. The diver can
look out the plexiglass dome, and move the arms with a joy
stick. The wasp has been used to make many undersea
discoveries. Now, several companies have been making and
developing remotely operated vehicles (ROVs). One called
the Scorpio can dive to a depth of 3,000 feet. It is
tethered to a vehicle on the surface where it is controlled
from, but it does not need a human inside. Scorpio's two
arms can lift up to 250 pounds water weight. Several
multimillion dollar projects are underway to improve ROVs
so they can dive to depths of 6,000 feet. They are needed
to salvage costly equipment, and offshore oil industry
hopes to use them to maintain rigs. ROBOTS OF THE FUTURE
Robotics and robot technology is advancing quickly. There
are many dreams to have a robot do something or everything
for you. Here are some ideas that we might see in the
future. Many people are working on robotic defense systems
that can protect the United States from destruction. Here
is one idea: To protect the Unites States from nuclear
missile attack, hundreds of nuclear battle stations would
be put in orbit. When the station detects a missile launch,
it move a hollow tube towards the missile. Then the station
launches a laser beam that hits the missile before it
reenters the atmosphere. To help astronauts retrieve
satellites from space, a remote manipulator operated from
inside the ship can be used. The manipulator would get to
the satellite by using four small thrusters. When it
reached the satellite, it would use a grappling device to
tow the satellite back to the ship.


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