Industrial Robot

Background

Industrial robots are mechanical devices which, to a certain degree, replicate human motions. They are used whenever there is a need to reduce the danger to a human, provide more strength or accuracy than a human, or when continuous operation is required. Most robots are stationary, but some move throughout the workplace delivering materials and supplies.

Many people think of robots as the humanoid-type monsters that are seen in science fiction and fantasy movies. While we may someday have the technical ability to produce such a machine, today's robots are actually quite simple devices. Motions that we take for granted—picking up a coin from the table, for instance—are considerably more difficult for a robot. Our brain processes thousands of variable bits of data from our eyes to instruct our arm, wrist, hand, and fingers to reach, grasp, and pick up the coin. Even the tactile feel of the coin constantly updates our brain to provide just enough finger pressure to grip the coin securely. Any variations in position are effortlessly compensated for in our brain. To easily and economically program an industrial robot to perform the same task, many of these variables must be restricted or eliminated. Position, reach, weight, and grasp should remain as consistent as possible so that variations do not result in missing or dropping the object. The computer that controls the robot must be programmed by a technician, to "teach" the machine to complete the motion. The areas where robots perform better than humans are in accuracy and repeatability. While some people could pick up the coin with similar motions each time, the robot can perform the operation with exactly the same motions without tiring. Many robots can repeat motions with an accuracy of a few thousandths of an inch and operate 24 hours a day. Because of this tireless, accurate work, robots are a growing segment of industrial equipment purchases. Most are used for repetitive painting and welding operations, while others, known as pick-and-place robots, are used to lift and place products into machines and packages.

History

Robots, or "robotics," are a segment of the broader science of automation. Automation uses machines and computers which can learn or compensate for varying conditions of operation. The term robot can be traced to the Czech word robota, which means compulsory labor. The term first appeared in 1921 in the play "R.U.R." (Rossum's Universal Robots) by Czech dramatist Karel Capek. The play described humanoid robots that destroyed their human makers—much the same plot of some modern science fiction thrillers.

Practical robots were first attempted after the development of the computer. In the late 1960s, the Stanford Research Institute designed and built an experimental robot called "SHAKEY." Using a television camera and a computer, this machine was capable of moving and arranging blocks into stacks. General Motors financed a program at the Massachusetts Institute of Technology in the mid-1970s to develop an automated robot for assembly purposes. Here, researcher Victor Scheinman invented the PUMA (programmable universal manipulator for assembly), and the entry of robots into American industry began.

Raw Materials

Robots are mostly built of common materials. Some specialized robots for clean room applications, the space program, or other "high tech" projects may use titanium metal and structural composites of carbon fibers. The operating environment and strength required are major factors in material selection.

Steel, cast iron, and aluminum are most often used for the arms and bases of robots. If the robot is mobile, they usually equip them with rubber tires for quiet operation and a positive grip on the floor. Robots contain a significant amount of electronics and wiring, and some are radio or laser controlled. The cylinders and other motion-generating mechanisms contain hydraulic oil or pressurized air. Hoses of silicone, rubber, and braided stainless steel connect these mechanisms to their control valves. To protect the robot from the environment, some exposed areas are covered with flexible neoprene shields and collapsible bellows. Electric motors and linear drives are purchased from automation suppliers along with the controller, or "brain." Controllers are housed in steel electrical cabinets located near the robot's work area or carried on board the robot itself.