A robot is a mechanical or virtual artificial agent. In practice, it is usually an electro-mechanical system which, by its appearance or movements, conveys a sense that it has intent or agency of its own. The word robot can refer to both physical robots and virtual software agents, but the latter are usually referred to as bots. There is no consensus on which machines qualify as robots, but there is general agreement among experts and the public that robots tend to do some or all of the following: move around, operate a mechanical arm, sense and manipulate their environment, and exhibit intelligent behavior, especially behavior which mimics humans or animals.
Stories of artificial helpers and companions and attempts to create them have a long history, but fully autonomous machines only appeared in the 20th century. The first digitally operated and programmable robot, the Unimate, was installed in 1961 to lift hot pieces of metal from a die casting machine and stack them. Today, commercial and industrial robots are in widespread use performing jobs more cheaply or with greater accuracy and reliability than humans. They are also employed for jobs which are too dirty, dangerous or dull to be suitable for humans. Robots are widely used in manufacturing, assembly and packing, transport, earth and space exploration, surgery, weaponry, laboratory research, and mass production of consumer and industrial goods.
People have a generally positive perception of the robots they actually encounter. Domestic robots for cleaning and maintenance are increasingly common in and around homes. There is anxiety, however, over the economic impact of automation and the threat of robotic weaponry, anxiety which is not helped by the many villainous, intelligent, acrobatic robots in popular entertainment. Compared with their fictional counterparts, real robots are still benign, dim-witted and clumsy.
The last property, the appearance of agency, is important when people are considering whether to call a machine a robot, or just a machine. (See anthropomorphism for examples of ascribing intent to inanimate objects.)
For robotic engineers, the physical appearance of a machine is less important than the way its actions are controlled. The more the control system seems to have agency of its own, the more likely the machine is to be called a robot. An important feature of agency is the ability to make choices.
However, for many laymen, if a machine appears to be able to control its arms or limbs, and especially if it appears anthropomorphic or zoomorphic (e.g. ASIMO or Aibo), it would be called a robot.
Even for a 3-axis CNC milling machine using the same control system as a robot arm, it is the arm which is almost always called a robot, while the CNC machine is usually just a machine. Having eyes can also make a difference in whether a machine is called a robot, since humans instinctively connect eyes with sentience. However, simply being anthropomorphic is not a sufficient criterion for something to be called a robot. A robot must do something; an inanimate object shaped like ASIMO would not be considered a robot.
The Robotics Institute of America (RIA) uses a broader definition: a robot is a "re-programmable multi-functional manipulator designed to move materials, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks". The RIA subdivides robots into four classes: devices that manipulate objects with manual control, automated devices that manipulate objects with predetermined cycles, programmable and servo-controlled robots with continuous point-to-point trajectories, and robots of this last type which also acquire information from the environment and move intelligently in response.
The word robot was introduced to the public by Czech writer Karel Čapek in his play R.U.R. (Rossum's Universal Robots), which premiered in 1921. The play begins in a factory that makes artificial people called robots, but they are closer to the modern ideas of androids and clones, creatures who can be mistaken for humans. They can plainly think for themselves, though they seem happy to serve. At issue is whether the robots are being exploited and the consequences of their treatment.
However, Karel Čapek himself did not coin the word; he wrote a short letter in reference to an etymology in the Oxford English Dictionary in which he named his brother, the painter and writer Josef Čapek, as its actual originator. In an article in the Czech journal Lidové noviny in 1933, he explained that he had originally wanted to call the creatures laboři (from Latin labor, work). However, he did not like the word, and sought advice from his brother Josef, who suggested "roboti". The word robota means literally work, labor or serf labor, and figuratively "drudgery" or "hard work" in Czech and many Slavic languages. Serfdom was outlawed in 1848 in Bohemia, so at the time Čapek wrote R.U.R., usage of the term robota had broadened to include various types of work, but the obsolete sense of "serfdom" would still have been known.
In the 4th century BC, the Greek mathematician Archytas of Tarentum postulated a mechanical steam-operated bird he called "The Pigeon". Hero of Alexandria created numerous user-configurable automated devices, and described machines powered by air pressure, steam and water. Su Song built a clock tower in China in 1088 featuring mechanical figurines that chimed the hours.
Al-Jazari (1136–1206), a Muslim inventor during the Artuqid dynasty, designed and constructed a number of automated machines, including kitchen appliances, musical automata powered by water, and the first programmable humanoid robots in 1206. The robots appeared as four musicians on a boat in a lake, entertaining guests at royal drinking parties. His mechanism had a programmable drum machine with pegs (cams) that bumped into little levers that operated percussion instruments. The drummer could be made to play different rhythms and different drum patterns by moving the pegs to different locations.
In 1738 and 1739, Jacques de Vaucanson exhibited several life-sized automatons: a flute player, a pipe player and a duck. The mechanical duck could flap its wings, crane its neck, and swallow food from the exhibitor's hand, and it gave the illusion of digesting its food by excreting matter stored in a hidden compartment. Complex mechanical toys and animals built in Japan in the 1700s were described in the Karakuri zui (Illustrated Machinery, 1796).
In 1926, Westinghouse Electric Corporation created Televox, the first robot put to useful work. They followed Televox with a number of other simple robots, including one called Rastus, made in the crude image of a black man. In the 1930s, they created a humanoid robot known as Elektro for exhibition purposes, including the 1939 and 1940 World's Fairs. In 1928, Japan's first robot, Gakutensoku, was designed and constructed by biologist Makoto Nishimura.
The first electronic autonomous robots were created by William Grey Walter of the Burden Neurological Institute at Bristol, England in 1948 and 1949. They were named Elmer and Elsie. These robots could sense light and contact with external objects, and use these stimuli to navigate.
The first truly modern robot, digitally operated and programmable, was invented by George Devol in 1954 and was ultimately called the Unimate. Devol sold the first Unimate to General Motors in 1960, and it was installed in 1961 in a plant in Trenton, New Jersey to lift hot pieces of metal from a die casting machine and stack them.
|First century A.D. and earlier||Descriptions of more than 100 machines and automata, including a fire engine, a wind organ, a coin-operated machine, and a steam-powered engine, in Pneumatica and Automata by Heron of Alexandria||Ctesibius of Alexandria, Philo of Byzantium, Heron of Alexandria, and others|
|1206||First programmable humanoid robots||Boat with four robotic musicians||Al-Jazari|
|c. 1495||Designs for a humanoid robot||Mechanical knight||Leonardo da Vinci|
|1738||Mechanical duck that was able to eat, flap its wings, and excrete||Digesting Duck||Jacques de Vaucanson|
|1800s||Japanese mechanical toys that served tea, fired arrows, and painted||Karakuri toys||Hisashige Tanaka|
|1921||First fictional automatons called "robots" appear in the play R.U.R.||Rossum's Universal Robots||Karel Čapek|
|1930s||Humanoid robot exhibited at the 1939 and 1940 World's Fairs||Elektro||Westinghouse Electric Corporation|
|1948||Simple robots exhibiting biological behaviors||Elsie and Elmer||William Grey Walter|
|1956||First commercial robot, from the Unimation company founded by George Devol and Joseph Engelberger, based on Devol's patents||Unimate||George Devol|
|1961||First installed industrial robot||Unimate||George Devol|
|1963||First palletizing robot||Palletizer||Fuji Yusoki Kogyo|
|1973||First robot with six electromechanically driven axes||Famulus||KUKA Robot Group|
|1975||Programmable universal manipulation arm, a Unimation product||PUMA||Victor Scheinman|
Many factory jobs are now performed by robots. This has led to cheaper mass-produced goods, including automobiles and electronics. Stationary manipulators used in factories have become the largest market for robots.
Some examples of factory robots:
Fears and concerns about robots have been repeatedly expressed in a wide range of books and films. A common theme is the development of a master race of conscious and highly intelligent robots, motivated to take over or destroy the human race. (See The Terminator, Runaway, Bladerunner, Robocop, the Replicators in Stargate, the Cylons in BattleStar Galactica, The Matrix, and I, Robot.) Some fictional robots are programmed to kill and destroy; others gain superhuman intelligence and abilities by upgrading their own software and hardware. Another common theme is the reaction, sometimes called the "uncanny valley", of unease and even revulsion at the sight of robots that mimic humans too closely. Frankenstein (1818), often called the first science fiction novel, has become synonymous with the theme of a robot or monster advancing beyond its creator.
Manuel De Landa has noted that "smart missiles" and autonomous bombs equipped with artificial perception can be considered robots, and they make some of their decisions autonomously. He believes this represents an important and dangerous trend in which humans are handing over important decisions to machines.
Marauding robots may have entertainment value, but unsafe use of robots constitutes an actual danger. A heavy industrial robot with powerful actuators and unpredictably complex behavior can cause harm, for instance by stepping on a human's foot or falling on a human. Most industrial robots operate inside a security fence which separates them from human workers, but not all. The first fatality involving a robot was Robert Williams, who was struck by a robotic arm at a casting plant in Flat Rock, Michigan on January 25, 1979. The second was 37-year-old Kenji Urada, a Japanese factory worker, in 1981. Urada was performing routine maintenance on the robot, but neglected to shut it down properly, and was accidentally pushed into a grinding machine.
The first reference in Western literature to mechanical servants appears in Homer's Iliad. In Book XVIII, Hephaestus, god of fire, creates new armor for the hero Achilles, assisted by robots. According to the Rieu translation, "Golden maidservants hastened to help their master. They looked like real women and could not only speak and use their limbs but were endowed with intelligence and trained in handwork by the immortal gods." Of course, the words "robot" or "android" are not used to describe them, but they are nevertheless mechanical devices human in appearance.
The most prolific author of stories about robots was Isaac Asimov (1920–1992), who placed robots and their interaction with society at the center of many of his works. Asimov carefully considered the problem of the ideal set of instructions robots might be given in order to lower the risk to humans, and arrived at his Three Laws of Robotics: a robot may not injure a human being or, through inaction, allow a human being to come to harm; a robot must obey orders given to it by human beings, except where such orders would conflict with the First Law; and a robot must protect its own existence as long as such protection does not conflict with the First or Second Law. These were introduced in his 1942 short story "Runaround", although foreshadowed in a few earlier stories. Later, Asimov added the Zeroth Law: "A robot may not harm humanity, or, by inaction, allow humanity to come to harm"; the rest of the laws are modified sequentially to acknowledge this.
According to the Oxford English Dictionary, the first passage in Asimov's short story "Liar!" (1941) that mentions the First Law is the earliest recorded use of the word robotics. Asimov was not initially aware of this; he assumed the word already existed by analogy with mechanics, hydraulics, and other similar terms denoting branches of applied knowledge.
For classes and types of robots see Robots.