The history of robots has its roots as far back as ancient myths and legends. Modern concepts were begun to be developed when the Industrial Revolution allowed the use of more complex mechanics and the subsequent introduction of electricity made it possible to power machines with small compact motors. After the 1920s the modern formulation of a humanoid machine was developed to the stage where it was possible to envisage human sized robots with the capacity for near human thoughts and movements, first envisaged millennia before. The first uses of modern robots were in factories as industrial robots - simple fixed machines capable of manufacturing tasks which allowed production without the need for human assistance. Digitally controlled industrial robots and robots making use of artificial intelligence have been built since the 1960s.

Chinese accounts relate a history of automata back to the 10th century BC when Yan Shi is credited with making an automaton resembling a human in an account from the Lie Zi text.

Western and Eastern civilisations have concepts of artificial servants and companions with a long history. Many ancient mythologies include artificial people, such as the mechanical servants built by the Greek god Hephaestus (Vulcan to the Romans), the clay golems of Jewish legend and clay giants of Norse legend.

Likely fictional, the Iliad illustrates the concept of robotics by stating that the god Hephaestus made talking mechanical handmaidens out of gold.^[1] Greek mathematician Archytas of Tarentum is reputed to have built a mechanical pigeon around 400 BC, possibly powered by steam, capable of flying. The clepsydra was made in 250 BC by Ctesibius of Alexandria, a physicist and inventor from Ptolemaic Egypt. Heron of Alexandria (10–70 AD) created programmable devices in the late 1st century AD, including one that allegedly could speak.

Aristotle took up an earlier reference in Homer's Iliad and speculated that automatons could someday bring about human equality by making the abolition of slavery possible in his book Politics (ca. 322 BC).

In ancient China, a curious account on automata is found in the Lie Zi text, written in the 3rd century BC. Within it there is a description of a much earlier encounter between King Mu of Zhou (1023-957 BC) and a mechanical engineer known as Yan Shi, an 'artificer'. The latter proudly presented the king with a life-size, human-shaped figure of his mechanical handiwork.^[2]

The king stared at the figure in astonishment. It walked with rapid strides, moving its head up and down, so that anyone would have taken it for a live human being. The artificer touched its chin, and it began singing, perfectly in tune. He touched its hand, and it began posturing, keeping perfect time...As the performance was drawing to an end, the robot winked its eye and made advances to the ladies in attendance, whereupon the king became incensed and would have had Yen Shih [Yan Shi] executed on the spot had not the latter, in mortal fear, instantly taken the robot to pieces to let him see what it really was. And, indeed, it turned out to be only a construction of leather, wood, glue and lacquer, variously coloured white, black, red and blue. Examining it closely, the king found all the internal organs complete—liver, gall, heart, lungs, spleen, kidneys, stomach and intestines; and over these again, muscles, bones and limbs with their joints, skin, teeth and hair, all of them artificial...The king tried the effect of taking away the heart, and found that the mouth could no longer speak; he took away the liver and the eyes could no longer see; he took away the kidneys and the legs lost their power of locomotion. The king was delighted.^[2]

Early water clocks are sometimes grouped in with the beginning of robotics. They began in China in the 6th century BC^[3] and the Greco-Roman world in the 4th century BC where the Clepsydra is known to have been used as a stop-watch for imposing a time limit on clients' visits in Athenian brothels.^[4]

The idea of artificial people in western mythology dates at least as far back as the ancient legends of Cadmus, who sowed dragon teeth that turned into soldiers, and the myth of Pygmalion, whose statue of Galatea came to life. In Greek mythology, the deformed god of metalwork (Vulcan or Hephaestus) created mechanical servants, ranging from intelligent, golden handmaidens to more utilitarian three-legged tables that could move about under their own power, and the bronze man Talos defended Crete.

Concepts akin to a robot can be found as long ago as the 4th century BC, when the Greek mathematician Archytas of Tarentum postulated a mechanical bird he called "The Pigeon" which was propelled by steam. Yet another early automaton was the clepsydra, made in 250 BC by Ctesibius of Alexandria, a physicist and inventor from Ptolemaic Egypt.^[5] Hero of Alexandria (10–70 AD) made numerous innovations in the field of automata, including one that allegedly could speak.

Taking up the earlier reference in Homer's Iliad, Aristotle speculated in his Politics (ca. 322 BC, book 1, part 4) that automatons could someday bring about human equality by making possible the abolition of slavery:

Hero of Alexandria (10–70 AD) created numerous "programmable" automated devices, including one that allegedly could speak.

The bible mentions the Jewish legend of the Golem, a clay creature animated by Kabbalistic magic. Similarly, in the Younger Edda, Norse mythology tells of a clay giant, Mökkurkálfi or Mistcalf, constructed to aid the troll Hrungnir in a duel with Thor, the God of Thunder.

The Cosmic Engine, a 10-metre (33 ft) clock tower built by Su Song in Kaifeng, China in 1088, featured mechanical mannequins that chimed the hours, ringing gongs or bells among other devices.^[6][7] Al-Jazari (1136–1206), an Arab Muslim inventor during the Artuqid dynasty, designed and constructed a number of automatic machines, including kitchen appliances, musical automata powered by water, and the first programmable humanoid robot in 1206. Al-Jazari's robot was a boat with four automatic musicians that floated on a lake to entertain guests at royal drinking parties. His mechanism had a programmable drum machine with pegs (cams) that bump into little levers that operate the percussion. The drummer could be made to play different rhythms and different drum patterns by moving the pegs to different locations.^[8]

Interest in automata was either mostly non-existent in medieval Europe, or unrecorded.^[9][10][11] Oriental automata did, however, find their way into the imaginary worlds of medieval literature. For instance, the Middle Dutch tale Roman van Walewein ("The Romance of Walewein", early 13th century) describes mechanical birds and angels producing sound by means of systems of pipes.^[12][13]

One of the first recorded designs of a humanoid robot was made by Leonardo da Vinci (1452–1519) in around 1495. Da Vinci's notebooks, rediscovered in the 1950s, contain detailed drawings of a mechanical knight in armour which was able to sit up, wave its arms and move its head and jaw.^[14] The design is likely to be based on his anatomical research recorded in the Vitruvian Man but it is not known whether he attempted to build the robot (see: Leonardo's robot).

Between 1500 and 1800, many automatons were built including ones capable of acting, drawing, flying, and playing music;^[10] several mechanical calculators were also built in this time period, some of the most famous ones are Wilhelm Schickard's "Calculating Clock", Blaise Pascal's "Pascaline", and the "Liebniz Stepped Drum", by Gottfried Wilhelm Leibniz.^[15] In 1533, Johannes Müller von Königsberg created an automaton eagle and fly made of iron; both could fly.^[10] John Dee is also famous for creating a wooden beetle, capable of flying.^[10]

Some of the most famous works of the period were created by Jacques de Vaucanson in 1737, including an automaton flute player, tambourine player, and his most famous work, "The Digesting Duck". Vaucanson's duck was powered by weights and was capable of imitating a real duck by flapping its wings (over 400 parts were in each of the wings alone), eat grain, digest it, and defecate by excreting matter stored in a hidden compartment.^[16]

John Kay invented his "flying shuttle" in 1733, and the "Spinning Jenny" was invented in 1764 by James Hargreaves, each radically increasing the speed of production in the weaving and spinning industries respectively.^[17][18] The Spinning Jenny is hand-powered and requires a skilled operator; Samuel Crompton's Spinning Mule first developed in 1779 is a fully automated power driven spinning machine capable of spinning hundreds of threads at once.

Richard Arkwright built a water powered weaving machine, and factory around it in 1781, starting the Industrial Revolution.^[19]

The Japanese craftsman Hisashige Tanaka, known as "Japan's Edison", created an array of extremely complex mechanical toys, some of which were capable of serving tea, firing arrows drawn from a quiver, or even painting a Japanese kanji character. The landmark text Karakuri Zui (Illustrated Machinery) was published in 1796.^[20]

By 1800, cloth production was completely automated.^[11] With the advent of the Industrial Revolution the idea of automata began to be applied to industry, as cost and time saving devices.

Improvements in the weaving industry had led to large amounts of automation, and the idea of programmable machines became popular with Charles Babbage's Analytical Engine^[10] Babbage conceived his Analytical Engine as a replacement for his uncompleted Difference Engine; this larger, more complex device would be able to perform multiple operations, and would be operated by punch cards. Construction of the Analytical Engine was never completed; work was begun in 1833.^[21] However, Ada Lovelace's work on the project has resulted in her being credited as the first computer programmer.

In 1837, the story of the Golem of Prague, a humanoid artificial intelligence activated by inscribing Hebrew letters on its forehead, based on Jewish folklore, was created by Jewish German writer Berthold Auerbach for his novel Spinoza.

George Boole invented a new type of symbolic logic in 1847 which was instrumental to the creation of computers and robots.^[10]

In 1898 Nikola Tesla publicly demonstrated a radio-controlled (teleoperated) boat, similar to a modern ROV. Based on his patents U.S. Patent 613,809, U.S. Patent 723,188 and U.S. Patent 725,605 for "teleautomation", Tesla hoped to develop the wireless torpedo into a weapon system for the US Navy (Cheney 1989).^[22]

The word robot was popularized by Czech author Karel Čapek in his 1921 play R.U.R. (Rossum's Universal Robots). According to Karel, his brother Josef was the actual inventor of the word "robot", creating the word from the Czech word "robota", meaning servitude.^[23] In 1927, Fritz Lang's Metropolis was released; the Maschinenmensch ("machine-human"), a gynoid humanoid robot, also called "Parody", "Futura", "Robotrix", or the "Maria impersonator" (played by German actress Brigitte Helm), was the first robot ever to be depicted on film.^[9] The world's first actual robot, a humanoid named Televox operated through the telephone system, was constructed in the United States in 1927. In 1928, Makoto Nishimura produced Japan's first robot, Gakutensoku.^[24]

In his 1936 paper "On Computable Numbers, with an Application to the Entscheidungsproblem"^[25] (submitted on 28 May 1936), Turing reformulated Kurt Gödel's 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with what are now called Turing machines, formal and simple devices. He proved that some such machine would be capable of performing any conceivable mathematical computation if it were representable as an algorithm, thus creating the basis for what is now called computer science.

Many robots were constructed before the dawn of computer-controlled servomechanisms, for the public relations purposes of major firms. Electro appeared in Westinghouse's pavilion at the 1939 New York World's Fair. Some were built in between such major public gatherings, such as Garco, made by Garrett AiResearch in the 1950s. These were essentially machines that could perform a few stunts, like the automatons of the 18th century.

Vannevar Bush created the first differential analyzer at the Massachusetts Institute Of Technology (MIT). Known as the Differential Analyzer, the computer could solve differential equations.^[26] 1940 brought about the creation of two electrical computers, John Vincent Atanasoff and Clifford Berry's Atanasoff-Berry Computer (ABC).

Ultimately, ideas from ABC were stolen for ENIAC.^[27]

In 1941 and 1942, Isaac Asimov formulated the Three Laws of Robotics, and in the process of doing so, coined the word "robotics".

In the UK, the Robinson machine was designed for the British war effort in cracking Enigma messages.^[28] This was done at the British code-breaking establishment at Bletchley Park; Ultra is the name for the intelligence so received.^[27][28] Robinson was superseded by Colossus, which was built in 1943 to decode FISH messages by the British group Ultra; it was designed by Tommy Flowers and was 100 to 1000 times faster than Robinson, and was the first fully electronic computer.^[29] The Bletchley machines were kept secret for decades, and so do not appear in histories of computing written until recently. After the war, Tommy Flowers joined the team that built the early Manchester computers.

In Germany, Konrad Zuse built the first fully programmable digital computer in the world (the Z3) in 1941; it would later be destroyed in 1944.^[30] Zuse was also known for building the first binary computer from 1936 to 1938, called the Z1; he also built the Z4, his only machine to survive World War II.^[30]

The first American programmable computer was completed in 1944 by Howard Aiken and Grace Hopper. The Mark I (as it was called) ran computations for the US Navy until 1959.^[31] ENIAC was built in 1946 and gained fame because of its reliability, speed, and versatility. John Presper Eckert and John W. Mauchly spent 3 years building ENIAC, which weighed over 60,000 lbs.^[32]

In 1948, Norbert Wiener formulated the principles of cybernetics, the basis of practical robotics.

The first Turtles (Elmo and Elsie) were created by pioneer roboticist William Grey Walter in 1949.^[10]

The first working digital computer to be sold was Zuse's Z4 in Germany; the fully electronic US BINAC was sold twelve months earlier in September 1949 but it never worked reliably at the customer's site due to mishandling in transit. Second was the UK's Ferranti Mark 1 delivered in February 1951, the first software programmable digital electronic computer to be sold that worked upon delivery. It was based on the world's first software programmable digital electronic computer, Manchester's SSME of 1948.

In 1950, UNIVAC I (also by Eckert and Mauchley) handled the US Census results; it was the third commercially marketed computer that worked on delivery (in December 1951).^[33]

The Turing test is proposed by Alan Turing in his 1950 paper Computing Machinery and Intelligence, which opens with the words: "I propose to consider the question, 'Can machines think?'"

After 1950 computers and robotics began to rapidly increase in both complexity and numbers as the technology had exponential growth in production, availability and capability.

In 1951 William Shockley invented the bipolar junction transistor, announced at a press conference on July 4, 1951. Shockley obtained a patent for this invention on September 25, 1951. In 1951 a computer called LEO became operational in the UK. It was built by Lyons for its own use: this was the world's first software programmable digital electronic computer for commercial applications, exploiting the US development of mercury delay line memory, and built with the support of the Cambridge EDSAC project. LEO was used for commercial work running business application programs, the first of which was rolled out 17 November 1951.

Eckert and Mauchly completed EDVAC in 1951. An improvement on ENIAC and UNIVAC, EDVAC used mercury delay lines to store data, making it the USA's first software stored program computer.^[34] In 1952, the television network CBS correctly predicted the election of Dwight D. Eisenhower as president using UNIVAC. In 1952 IBM announced its 701 model computer, marketed towards scientific use, it was designed by Nathaniel Rochester.^[35] Stanislaw Ulam and physicist Paul Stein converted MANIAC I (used for solving calculations involved in creating the hydrogen bomb) to play a modified game of chess in 1956; it was the first computer to beat a human in a game of chess.^[36] The term "Artificial Intelligence was created at a conference held at Dartmouth College in 1956.^[37] Alan Newell, J. C. Shaw, and Herbert Simon pioneered the newly created artificial intelligence field with the Logic Theory Machine (1956), and the General Problem Solver in 1957.^[38] In 1958, John McCarthy and Marvin Minsky started the MIT Artificial Intelligence lab with $50,000.^[39] John McCarthy also created LISP in the summer of 1958, a programming language still important in artificial intelligence research.^[40] Jack Kilby and Robert Noyce invented the integrated circuit or "chip" in 1959; the inventors worked independent of each other. This development eventually revolutionized computers by affecting both the size and speed.^[41]

Unimate, the first industrial robot ever created began work on the General Motors assembly line in 1961; the machine was conceived in 1954 by George Devol. Unimate was manufactured by Unimation. Unimate is remembered as the first industrial robot.^[42] In 1962 John McCarthy founded the Stanford Artificial Intelligence Laboratory at Stanford University.^[43] The Rancho Arm was developed as a robotic arm to help handicapped patients at the Rancho Los Amigos Hospital in Downey, California; this computer controlled arm was bought by Stanford University in 1963.^[44] IBM announced its IBM System/360 in 1964. The system was heralded as being more powerful, faster, and more capable than its predecessors.^[45] In 1965, Gordon Moore, a co-founder of Intel in 1968, develops what will become known as Moore's Law; the idea that the number of components capable of being built onto a chip will double every two years.^[46] The same year, doctoral student Edward Feigenbaum, geneticist and biochemist Joshua Lederberg, and Bruce Buchanan (who held a degree in philosophy) begin work on the DENDRAL, an expert system designed to work in the field of organic chemistry.^[47] Feigenbaum also founded the Heuristic Programming Project in 1965, it later became the Stanford Knowledge Systems Artificial Intelligence Laboratory.^[11] The program Mac Hack was also written in 1966; it beat artificial intelligence critic Hubert Dreyfus in a game of chess. The program was created by Richard Greenblatt.^[48] Seymour Papert created the Logo programming language in 1967. It was designed as an educational programming language.^[49] The film 2001: A Space Odyssey was released in 1968; the movie prominently features HAL 9000, a malevolent artificial intelligence unit which controls a spacecraft.^[50] Marvin Minsky created the Tentacle Arm in 1968; the arm was computer controlled and its 12 joints were powered by hydraulics.^[44] Mechanical Engineering student Victor Scheinman created the Stanford Arm in 1969; the Stanford Arm is recognized as the first electronic computer controlled robotic arm (Unimate's instructions were stored on a magnetic drum).^[44] The first floppy disc was released in 1970. It measured eight inches in diameter and read-only.^[51] The first mobile robot capable of reasoning about its surroundings, Shakey was built in 1970 by the Stanford Research Institute. Shakey combined multiple sensor inputs, including TV cameras, laser rangefinders, and "bump sensors" to navigate.^[44] In the winter of 1970, the Soviet Union explored the surface of the moon with the lunar vehicle Lunokhod 1, the first roving remote-controlled robot to land on another world.

The first microprocessor, called the 4004 was created by Ted Hoff at Intel in 1971. Measuring 1/8 of an inch by 1/16 of an inch, the chip itself was more powerful than ENIAC.^[52] Artificial intelligence critic Hubert Dreyfuss published his influential book "What Computers cannot Do" in 1972.^[53] Douglas Trumbull's "Silent Running" was released in 1972; the movie was notable for the three robot co-stars, named Huey, Dewey, and Louie.^[54] Released in 1973 was the logic based programming language PROLOG; this logic based language becomes important in the field of artificial intelligence.^[55] Freddy and Freddy II, both built in the United Kingdom, were robots capable of assembling wooden blocks in a period of several hours.^[56] German based company KUKA built the world's first industrial robot with six electromechanically driven axes, known as FAMULUS.^[57] In 1974, David Silver designed The Silver Arm; the Silver Arm was capable of fine movements replicating human hands. Feedback was provided by touch and pressure sensors and analyzed by a computer.^[44] MYCIN, an expert system developed to study decisions and prescriptions relating to blood infections. MYCIN was written in Lisp.^[58] Marvin Minsky published his landmark paper "A Framework for Representing Knowledge" on artificial intelligence.^[59] By 1975, four expert systems relating to medicine had been created; PIP, MYCIN, CASNET, and Internist.^[11] 1975: more than 5,000 computers were sold in the United States, and the first personal computer was introduced.^[11] The Kurzweil Reading Machine (invented by Raymond Kurzweil), intended to help the blind, was released in 1976. Capable of recognizing characters, the machine formulated pronunciation based on programmed rules.^[60] Based on studies of flexible objects in nature (such as elephant trunks and the vertebrae of snakes), Shigeo Hirose designed the Soft Gripper in 1976 the gripper was capable of conforming to the object it was grasping.^[44] The knowledge based system Automated Mathematician was presented by Douglas Lenat in 1976 as part of his doctoral dissertation. Automated Mathematician began with a knowledge of 110 concepts and rediscovered many mathematical principles; Automated Mathematician was written in Lisp.^[61] Joseph Weizenbaum (creator of ELIZA, a program capable of simulating a Rogerian physcotherapist) published Computer Power and Human Reason, presenting an argument against the creation of artificial intelligence.^[62] Steven Jobs and Stephen Wozniak created the Apple Computer in 1977, and released the Apple II.^[63] George Lucas' movie Star Wars was also released in 1977. Star Wars featured two robots; an android named C-3PO and R2-D2, both of which become extremely iconic as robots.^[64][65] Voyagers 1 and 2 were launched in 1977 to explore the solar system. The 30 year old robotic space probes continue to transmit data back to earth and are approaching the heliopause and the interstellar medium.^[66] The SCARA, Selective Compliance Assembly Robot Arm, was created in 1978 as an efficient, 4-axis robotic arm. Best used for picking up parts and placing them in another location, the SCARA was introduced to assembly lines in 1981.^[67] XCON, an expert system designed to customize orders for industrial use, was released in 1979.^[68] The Stanford Cart successfully crossed a room full of chairs in 1979. The Stanford Cart relied primarily on stereo vision to navigate and determine distances.^[44] The Robotics Institute at Carnegie Mellon University was founded in 1979 by Raj Reddy.^[69]

Takeo Kanade created the first "direct drive arm" in 1981. The first of its kind, the arm's motors were contained within the robot itself, eliminating long transmissions.^[70] IBM released its first personal computer (PC) in 1981; the name of the computer was responsible for popularizing the term "personal computer".^[71] Prospector a "computer-based consultation program for mineral exploration",^[72] created in 1976, discovered an unknown deposit of molybdenum in Washington state. The expert system had been updated annually since its creation.^[73] The Fifth Generation Computer Systems Project (FGCS) was started in 1982. Its goals were knowledge based information processing and massive parallelism in a supercomputer, artificial intelligence like system.^[74] Cyc, a project to create a database of common sense for artificial intelligence, was started in 1984 by Douglas Leant. The program attempts to deal with ambiguity in language, and is still underway.^[75] The first program to publish a book, the expert system Racter, programmed by William Chamberlain and Thomas Etter, wrote the book "The Policeman's Beard is Half-Constructed" in 1983. It is now thought that a system of complex templates were used.^[76] In 1984 Wabot-2 was revealed; capable of playing the organ, Wabot-2 had 10 fingers and two feet. Wabot-2 was able to read a score of music and accompany a person.^[77] In 1985, Kawasaki Heavy Industries' license agreement with Unimation was terminated; Kawasaki began to produce its own robots. Their first robot was released one year later.^[78] By 1986, artificial intelligence revenue was about $1 billion US dollars. Chess playing programs HiTech and Deep Thought defeated chess masters in 1989. Both were developed by Carnegie Mellon University; Deep Thought development paved the way for the Deep Blue.^[79] In 1986, Honda began its humanoid research and development program to create robots capable of interacting successfully with humans.^[80] Artificial intelligence related technologies, not including robots, now produce a revenue of $1.4 billion US dollars.^[11] In 1988, Stäubli Group purchased Unimation.^[44] The Connection Machine was built in 1988 by Daniel Hillis; the supercomputer used 64,000 processors simultaneously.^[81] A hexapodal robot named Genghis was revealed by MIT in 1989. Genghis was famous for being made quickly and cheaply due to construction methods; Genghis used 4 microprocessors, 22 sensors, and 12 servo motors.^[82] Rodney Brooks and Anita M. Flynn published "Fast, Cheap, and Out of Control: A Robot Invasion of The Solar System". The paper advocated creating smaller cheaper robots in greater numbers to increase production time and decrease the difficulty of launching robots into space.^[83]

While competing in a 1993 NASA sponsored competition, Carnegie Mellon University's eight legged robot Dante failed to collect gases from Mt. Erebus because of a broken fiber optic cable. Dante was designed to scale slopes and harvest gases near the surface of the magma; however, the failure in the cable did not permit the robot to enter the active volcano.^[84] In 1994, Dante II entered Mt. Spurr and successfully sampled the gases within the volcano.^[85] The biomimetic robot RoboTuna was built by doctoral student David Barrett^{[disambiguation needed]} at the Massachusetts Institute of Technology in 1996 to study how fish swim in water. RoboTuna is designed to swim and resemble a blue fin tuna.^[86] Invented by Dr. John Adler, in 1994, the Cyberknife (a stereotactic radiosurgery performing robot) represented a faster method of performing surgery with equivalent accuracy to one done by human doctors.^[87] Honda's P2 humanoid robot was first shown in 1996. Standing for "Prototype Model 2", P2 was an integral part of Honda's humanoid development project; over 6 feet tall, P2 was smaller than its predecessors and appeared to be more human-like in its motions.^[88] Expected to only operate for seven days, the Sojourner rover finally shuts down after 83 days of operation in 1997. This small robot (only weighing 23 lbs) performed semi-autonomous operations on the surface of Mars as part of the Mars Pathfinder mission; equipped with an obstacle avoidance program, Sojourner was capable of planning and navigating routes to study the surface of the planet. Sojourner's ability to navigate with little data about its environment and nearby surroundings allowed the robot to react to unplanned events and objects.^[89] Also in 1997, IBM's chess playing program Deep Blue beat the then current World Chess Champion Garry Kasparov playing at the "Grandmaster" level. The super computer was a specialized version of a framework produced by IBM, and was capable of processing twice as many moves per second as it had during the first match (which Deep Blue had lost), reportedly 200,000,000 moves per second. The event was broadcast live over the internet and received over 74 million hits.^[90] The P3 humanoid robot was revealed by Honda in 1998 as a part of the company's continuing humanoid project.^[91] In 1999, Sony introduced the AIBO, a robotic dog capable of interacting with humans, the first models released in Japan sold out in 20 minutes.^[92] Honda revealed the most advanced result of their humanoid project in 2000, named ASIMO. ASIMO is capable of running, walking, communication with humans, facial and environmental recognition, voice and posture recognition, and interacting with its environment.^[93] Sony also revealed its Sony Dream Robots, small humanoid robots in development for entertainment.^[94] In October 2000, the United Nations estimated that there were 742,500 industrial robots in the world, with more than half of the robots being used in Japan.^[10]

In April 2001, the Canadarm2 was launched into orbit and attached to the International Space Station. The Canadarm2 is a larger, more capable version of the arm used by the Space Shuttle and is hailed as being "smarter."^[95] Also in April, the Unmanned Aerial Vehicle Global Hawk made the first autonomous non-stop flight over the Pacific Ocean from Edwards Air Force Base in California to RAAF Base Edinburgh in Southern Australia. The flight was made in 22 hours.^[96] The popular Roomba, a robotic vacuum cleaner, was first released in 2002 by the company iRobot.^[97] In 2004, Cornell University revealed a robot capable of self-replication; a set of cubes capable of attaching and detaching, the first robot capable of building copies of itself.^[98] On January 3 and 24 the Mars rovers Spirit and Opportunity land on the surface of Mars. Launched in 2003, the two robots will drive many times the distance originally expected, and are still operating.^[99] All 15 teams competing in the 2004 DARPA Grand Challenge failed to complete the course, with no robot successfully navigating more than five percent of the 150 mile off road course, leaving the $1 million dollar prize unclaimed.^[100] In the 2005 DARPA Grand Challenge, five teams completed the off-road course; Stanford University's Stanley won first place and the $2 million dollar prize.^[101] Also in 2005, Honda revealed a new version of its ASIMO robot, updated with new behaviors and capabilities.^[102] In 2006, Cornell University revealed its "Starfish" robot, a 4-legged robot capable of self modeling and learning to walk after having been damaged.^[103] In September 2007, Google announced its Lunar X Prize. The Lunar X Prize offers 30 million dollars to the first private company which lands a rover on the moon and sends images back to earth.^[104] In 2007, TOMY launched the entertainment robot, i-sobot, which is a humanoid bipedal robot that can walk like a human beings and performs kicks and punches and also some entertaining tricks and special actions under "Special Action Mode".