Continuous track called tank tread or caterpillar track, is a system of vehicle propulsion in which a continuous band of treads or track plates is driven by two or more wheels. This band is made of modular steel plates in the case of military vehicles and heavy equipment, or synthetic rubber reinforced with steel wires in the case of lighter agricultural or construction vehicles; the large surface area of the tracks distributes the weight of the vehicle better than steel or rubber tyres on an equivalent vehicle, enabling a continuous tracked vehicle to traverse soft ground with less likelihood of becoming stuck due to sinking. The prominent treads of the metal plates are both hard-wearing and damage resistant in comparison to rubber tyres; the aggressive treads of the tracks provide good traction in soft surfaces but can damage paved surfaces, so some metal tracks can have rubber pads installed for use on paved surfaces. Continuous tracks can be traced back as far as 1770 and today are used on a variety of vehicles, including bulldozers, excavators and tractors.
Polish mathematician and inventor Józef Maria Hoene-Wroński conceived of the idea in the 1830s. The British polymath Sir George Cayley patented a continuous track, which he called a "universal railway". In 1837, a Russian inventor Dmitry Zagryazhsky designed a "carriage with mobile tracks" which he patented the same year, but due to a lack of funds and interest from manufacturers he was unable to build a working prototype, his patent was voided in 1839. Although not a continuous track in the form encountered today, a dreadnaught wheel or "endless railway wheel" was patented by the British Engineer James Boydell in 1846. In Boydell's design, a series of flat feet are attached to the periphery of the wheel, spreading the weight. A number of horse-drawn wagons and gun carriages were deployed in the Crimean War, waged between October 1853 and February 1856, the Royal Arsenal at Woolwich manufacturing dreadnaught wheels. A letter of recommendation was signed by Sir William Codrington, the General commanding the troops at Sebastopol.
Boydell patented improvements to his wheel in 1854 – the year his dreadnaught wheel was first applied to a steam engine – and 1858, the latter an impracticable palliative measure involving the lifting one or other of the driving wheels to facilitate turning. A number of manufacturers including Richard Bach, Richard Garrett & Sons, Charles Burrell & Sons and Clayton & Shuttleworth applied the Boydell patent under licence; the British military were interested in Boydell's invention from an early date. One of the objectives was to transport Mallet's Mortar, a giant 36 in weapon, under development, but, by the end of the Crimean war, the mortar was not ready for service. A detailed report of the tests on steam traction, carried out by a select Committee of the Board of Ordnance, was published in June 1856, by which date the Crimean War was over the mortar and its transportation became irrelevant. In those tests, a Garrett engine was put through its paces on Plumstead Common; the Garrett engine featured in the Lord Mayor's show in London, in the following month that engine was shipped to Australia.
A steam tractor employing dreadnaught wheels was built at Bach's Birmingham works, was used between 1856 and 1858 for ploughing in Thetford. Between late 1856 and 1862 Burrell manufactured not less than a score of engines fitted with dreadnaught wheels. In April 1858, "The Engineer" gave a brief description of a Clayton & Shuttleworth engine fitted with dreadnaught wheels, supplied not to the Western Allies, but to the Russian government for heavy artillery haulage in the Crimea, in the post-war period. Steam tractors fitted with dreadnaught wheels had a number of shortcomings and, notwithstanding the creations of the late 1850s, were never used extensively. In August 1858, more than two years after the end of the Crimean War, John Fowler filed British Patent No. 1948 on another form of "Endless Railway". In his illustration of the invention, Fowler used a pair of wheels of equal diameter on each side of his vehicle, around which pair of toothed wheels ran a'track' of eight jointed segments, with a smaller jockey/drive wheel between each pair of wheels, to support the'track'.
Comprising only eight sections, the'track' sections are essentially'longitudinal', as in Boydell's initial design. Fowler's arrangement is a precursor to the multi-section caterpillar track in which a large number of short'transverse' treads are used, as proposed by Sir George Caley in 1825, rather than a small number of long'longitudinal' treads. Further to Fowler's patent of 1858, in 1877, a Russian, Fyodor Blinov, created a tracked vehicle called "wagon moved on endless rails", it was pulled by horses. Blinov received a patent for his "wagon" in 1878. From 1881 to 1888 he developed a steam-powered caterpillar-tractor; this self-propelled crawler was tested and featured at a farmers' exhibition in 1896. Steam traction engines were used at the end of the 19th century in the Boer Wars, but neither dreadnaught wheels nor continuous tracks were used, rather "roll-out" wooden plank roads were thrown under the wheels as required. In short, whilst the development of the continuous track engaged the attention of a number of inventors in the 18th and 19th centuries, the general use and exploitation of the continuous track belonged to the 20th century.
A little-known American inventor, Henry T. Stith, developed a continuous track prototype which was, in multiple forms, patented in 1873, 1880, 1900; the last
History of robots
The history of robotics has its origins in the ancient world. The modern concept began to be developed with the onset of the Industrial Revolution, which allowed the use of complex mechanics, the subsequent introduction of electricity; this made it possible to power machines with small compact motors. In the early 20th century, the notion of a humanoid machine was developed. Today, one can envisage human-sized robots with the capacity for near-human thoughts and movement; the first uses of modern robots were in factories as industrial robots – simple fixed machines capable of manufacturing tasks which allowed production with less need for human assistance. Digitally controlled industrial robots and robots using artificial intelligence have been built since the 2000s. Concepts of artificial servants and companions date at least as far back as the ancient legends of Cadmus, said to have sown dragon teeth that turned into soldiers and Pygmalion whose statue of Galatea came to life. Many ancient mythologies included artificial people, such as the talking mechanical handmaidens built by the Greek god Hephaestus out of gold, the clay golems of Jewish legend and clay giants of Norse legend.
In Greek mythology, Hephaestus created utilitarian three-legged tables that could move about under their own power, a bronze man, that defended Crete. Talos was destroyed by Medea who cast a lightning bolt at his single vein of lead. To take the golden fleece Jason was required to tame two fire-breathing bulls with bronze hooves. In ancient Egypt statues of divinities were made of metal or wood; the statues were played a key role in religious ceremonies. They were believed to have a soul, derived from the divinity. In the New Kingdom of Egypt, from the 16th century BC till the 11th century BC, ancient Egyptians would consult these statues for advice; the statues would reply with a movement of the head. According to Egyptian lore, pharaoh Hatshepsut dispatched her squadron to the "Land of Incense" after consulting with the statue of Amun; the Buddhist scholar Daoxuan described humanoid automata crafted from metals that recite sacred texts in a cloister which housed a fabulous clock. The "precious metal-people" weeped.
Humanoid automations feature in the Epic of King Gesar, a Central Asian cultural hero. Early Chinese lore on the legendary carpenter Lu Ban and the philosopher Mozi described mechanical imitations of animals and demons; the implications of humanoid automations were discussed in Liezi, a compilation of Daoist texts which went on to become a classic. In chapter 5 King Mu of Zhou is on tour of the West and upon asking the craftsman Master Yan "What can you do?" the royal court is presented with an artificial man. The automation was indistinguishable from a human and performed various tricks for the king and his entourage, but the king flew into a rage when the automation started to flirt with the ladies in attendance and threatened the automation with execution. So the craftsman revealed the inner workings of the artificial man; the king is fascinated and experiments with the functional interdependence of the automation by removing different organlike components. The king marveled "is it possible for human skill to achieve as much as the Creator?" and confiscated the automation.
A similar tale can be found in the near contemporary Indian Buddhist Jataka tales, but here the intricacy of the automation does not match that of Master Yan. Prior to the introduction of Buddhism in the Common Era, Chinese philosophers did not consider the distinction between appearance and reality; the Liezi likens human creative powers to that of the Creator. The Indian Lokapannatti, a collection of cycles and lores produced in the 11th or 12th centuries AD, tells the story of how an army of automated soldiers were crafted to protect the relics of Buddha in a secret stupa; the plans for making such humanoid automations were stolen from the kingdom of Rome, a generic term for the Greco-Roman-Byzantine culture. According to the Lokapannatti, the Yavanas used the automations to carry out trade and farming, but captured and executed criminals. Roman automation makers who left the kingdom were killed by the automations. According to the Lokapannatti, the emperor Asoka hears the story of the secret stupa and sets out to find it.
Following a battle between with the fierce warrior automations, Asoka finds the long-lived engineer who had constructed the automations and is shown how to dismantle and control them. Thus emperor Asoka manages to command a large army of automated warriors; this Indian tale reflects the fear of losing control of artificial beings, expressed in Greek myths about the dragon-teeth army. Inspired by European Christian legend medieval Europeans devised brazen heads that could answer questions posed to them. Albertus Magnus was supposed to have constructed an entire android which could perform some domestic tasks, but it was destroyed by Albert's student Thomas Aquinas for disturbing his thought; the most famous legend concerned a bronze head devised by Roger Bacon, destroyed or scrapped after he missed its moment of operation. Automata resembling humans or animals were popular in the imaginary worlds of medieval literature. Mechanical automata were constructed in the 10th century BC in the Western Zhou Dynasty.
The artisan Yan Shi made humanoid automata that could dance. The machine is said to have possessed lifelike organs, like bones and joints; the Cosmic Engine, a 10-me
An articulated robot is a robot with rotary joints. Articulated robots can range from simple two-jointed structures to systems with 10 or more interacting joints, they are powered by a variety including electric motors. Some types of robots, such as robotic arms, can be non-articulated. Articulated Robot: See Figure. An articulated robot uses all; the joints are arranged in a “chain”, so that one joint supports another further in the chain. Continuous Path: A control scheme whereby the inputs or commands specify every point along a desired path of motion; the path is controlled by the coordinated motion of the manipulator joints. Degrees Of Freedom: The number of independent motions in which the end effector can move, defined by the number of axes of motion of the manipulator. Gripper: A device for grasping or holding, attached to the free end of the last manipulator link. Payload: The maximum payload is the amount of weight carried by the robot manipulator at reduced speed while maintaining rated precision.
Nominal payload is measured at maximum speed. These ratings are dependent on the size and shape of the payload. Pick And Place Cycle: See Figure. Pick and place Cycle is the time, in seconds, to execute the following motion sequence: Move down one inch, grasp a rated payload. Reach: The maximum horizontal distance from the center of the robot base to the end of its wrist. Accuracy: See Figure; the difference between the point that a robot is trying to achieve and the actual resultant position. Absolute accuracy is the difference between a point instructed by the robot control system and the point achieved by the manipulator arm, while repeatability is the cycle-to-cycle variation of the manipulator arm when aimed at the same point. Repeatability: See Figure; the ability of a system or mechanism to repeat the same motion or achieve the same points when presented with the same control signals. The cycle-to-cycle error of a system when trying to perform a specific task Resolution: See Figure; the smallest increment of motion or distance that can be detected or controlled by the control system of a mechanism.
The resolution of any joint is a function of encoder pulses per revolution and drive ratio, dependent on the distance between the tool center point and the joint axis. Robot Program: A robot communication program for IBM and compatible personal computers. Provides terminal emulation and utility functions; this program can record all of the user memory, some of the system memory to disk files. Maximum Speed: The compounded maximum speed of the tip of a robot moving at full extension with all joints moving in complimentary directions; this speed is the theoretical maximum and should under no circumstances be used to estimate cycle time for a particular application. A better measure of real world speed is place cycle time. For critical applications, the best indicator of achievable cycle time is a physical simulation. Servo Controlled: Controlled by a driving signal, determined by the error between the mechanism's present position and the desired output position. Via Point: A point through which the robot's tool should pass without stopping.
Work Envelope: A three-dimensional shape that defines the boundaries that the robot manipulator can reach. Degrees of freedom Articulated soft robotics Robotics suite Industrial robot Robotic arms and cranes used in spaceflight: Canadarm, used on the Space Shuttle Mobile Servicing System known as the Canadarm2, used on the ISS European Robotic Arm, a fourth robotic arm to be installed on the ISS in 2017 The Japanese Remote Manipulator System, used on the ISS JEM module Kibo Dextre known as the Special Purpose Dexterous Manipulator, used on the ISS Strela, a manually operated arm used on the Russian Orbital Segment of the ISS to perform similar tasks as the Mobile Servicing System
Competitions and prizes in artificial intelligence
There are a number of competitions and prizes to promote research in artificial intelligence. The David E. Rumelhart prize is an annual award for making a "significant contemporary contribution to the theoretical foundations of human cognition"; the prize is $100,000. The Human-Competitive Award is an annual challenge started in 2004 to reward results "competitive with the work of creative and inventive humans"; the prize is $10,000. Entries are required to use evolutionary computing; the IJCAI Award for Research Excellence is a biannual award given at the IJCAI conference to researcher in artificial intelligence as a recognition of excellence of their career. The 2011 Federal Virtual World Challenge, advertised by The White House and sponsored by the U. S. Army Research Laboratory's Simulation and Training Technology Center, held a competition offering a total of $52,000 USD in cash prize awards for general artificial intelligence applications, including "adaptive learning systems, intelligent conversational bots, adaptive behavior" and more.
The Machine Intelligence Prize is awarded annually by the British Computer Society for progress towards machine intelligence. The Kaggle - "the world's largest community of data scientists compete to solve most valuable problems"; the Loebner prize is an annual competition to determine the best Turing test competitors. The winner is the computer system that, in the judges' opinions, demonstrates the "most human" conversational behaviour, they have an additional prize for a system that in their opinion passes a Turing test; this second prize has not yet been awarded. The International Aerial Robotics Competition is a long-running event begun in 1991 to advance the state of the art in autonomous air vehicles; this competition is restricted to university teams. Key to this event is the creation of flying robots which must complete complex missions without any human intervention. Successful entries are able to interpret their environment and make real-time decisions based only on a high-level mission directive.
In 2000, a $30,000 prize was awarded during the 3rd Mission, in 2008, $80,000 in prize money was awarded at the conclusion of the 4th Mission. The DARPA Grand Challenge is a series of competitions to promote driverless car technology, aimed at a congressional mandate stating that by 2015 one-third of the operational ground combat vehicles of the US Armed Forces should be unmanned. While the first race had no winner, the second awarded a $2 million prize for the autonomous navigation of a hundred-mile trail, using GPS, computers and a sophisticated array of sensors. In November 2007, DARPA introduced the DARPA Urban Challenge, a sixty-mile urban area race requiring vehicles to navigate through traffic. In November 2010 the US Armed Forces extended the competition with the $1.6 million prize Multi Autonomous Ground-robotic International Challenge to consider cooperation between multiple vehicles in a simulated-combat situation. Roborace will be a global motorsport championship with autonomously driving, electrically powered vehicles.
The series will be run as a support series during the Formula E championship for electric vehicles. This will be the first global championship for driverless cars; the Netflix Prize was a competition for the best collaborative filtering algorithm that predicts user ratings for films, based on previous ratings. The competition was held by an online DVD-rental service; the prize was $1,000,000. The Pittsburgh Brain Activity Interpretation Competition will reward analysis of fMRI data "to predict what individuals perceive and how they act and feel in a novel Virtual Reality world involving searching for and collecting objects, interpreting changing instructions, avoiding a threatening dog." The prize in 2007 was $22,000. The Face Recognition Grand Challenge aimed to advance face recognition technology; the American Meteorological Society's artificial intelligence competition involves learning a classifier to characterise precipitation based on meteorological analyses of environmental conditions and polarimetric radar data.
The RoboCup and FIRA are annual international robot soccer competitions. The International RoboCup Federation challenge is by 2050 "a team of autonomous humanoid robot soccer players shall win the soccer game, comply with the official rule of the FIFA, against the winner of the most recent World Cup." The Herbrand Award is a prize given by CADE Inc. to honour persons or groups for important contributions to the field of automated deduction. The prize is $1000; the CADE ATP System Competition is a yearly competition of automated theorem provers for classical first order logic associated with the CADE and IJCAR conferences. The competition was part of the Alan Turing Centenary Conference in 2012, with total prizes of 9000 GBP given by Google; the SUMO prize is an annual prize for the best open source ontology extension of the Suggested Upper Merged Ontology, a formal theory of terms and logical definitions describing the world. The prize is $3000; the Hutter Prize for Lossless Compression of Human Knowledge is a cash prize which rewards compression improvements on a specific 100 MB English text file.
The prize awards 500 euros for each one percent improvement, up to €50,000. The organizers believe that text compression and AI are equivalent problems and 3 prizes were given, at around € 2k; the Cyc TPTP Challenge is a competition to develop reasoning methods for the Cyc comprehensive ontology and database of
James Maury Henson was an American puppeteer, cartoonist, director and screenwriter, who achieved worldwide notice as the creator of The Muppets and Fraggle Rock. Born in Greenville, Mississippi, he was raised in Leland and Hyattsville, Maryland. Henson began developing puppets while attending high school, he created Sam and Friends while he was a freshman at the University of Maryland, College Park, a five-minute sketch-comedy puppet show that appeared on television. He graduated from the University of Maryland with a degree in home economics, after which he produced coffee advertisements and developed some experimental films, he founded Inc. in 1958, which became The Jim Henson Company. Henson joined the children's educational television program Sesame Street where he helped to develop characters for the series, he appeared on the sketch comedy show Saturday Night Live. He produced The Muppet Show in 1976, after scrapping plans for a Broadway show, he gained attention for his creations Kermit the Frog, Rowlf the Dog and Ernie and he was involved with Sesame Street for over 20 years.
During the years of his life, he founded the Jim Henson Foundation and Jim Henson's Creature Shop. He won the Emmy Award twice for his involvement in The Jim Henson Hour. Henson died in May 1990 at age 53 from toxic shock syndrome, an unexpected event, lamented in the media and entertainment industry. In the weeks following his death, he was celebrated with a wave of tributes, he was posthumously inducted into the Hollywood Walk of Fame in 1991 and was selected to be one of the Disney Legends in 2011. James Maury Henson was born in Greenville, Mississippi, on September 24, 1936, the younger of two children of Paul Ransom Henson, an agronomist for the United States Department of Agriculture and his wife Betty Marcella, he was raised as a Christian Scientist and spent his early childhood in Leland, before moving with his family to University Park, Maryland in the late 1940s, near Washington, DC. He remembered the arrival of the family's first television as "the biggest event of his adolescence," having been influenced by radio ventriloquist Edgar Bergen and the early television puppets of Burr Tillstrom on Kukla and Ollie and Bil and Cora Baird.
He remained a Christian Scientist at least into his twenties, when he would teach Sunday School, but he wrote to a Christian Science church in 1975 to inform them that he was no longer a practising member. Henson began working for WTOP-TV in 1954 while attending Northwestern High School, creating puppets for a Saturday-morning children's show called The Junior Morning Show, he enrolled at the University of Maryland, College Park as a studio arts major upon graduation, thinking that he might become a commercial artist. A puppetry class offered in the applied arts department introduced him to the craft and textiles courses in the College of Home economics, he graduated in 1960, earning a bachelor of science degree in home economics; as a freshman, he had been asked to create Sam and Friends, a five-minute puppet show for WRC-TV. The characters on Sam and Friends were forerunners of the Muppets, the show included a prototype of Henson's most famous character Kermit the Frog. Henson remained at WRC from 1954 to 1961.
In the show, Henson began experimenting with techniques that changed the way in which puppetry was used on television, including using the frame defined by the camera shot to allow the puppet performer to work from off-camera. He believed that television puppets needed to have "life and sensitivity" and began making characters from flexible, fabric-covered foam rubber, allowing them to express a wider array of emotions at a time when many puppets were made of carved wood. A marionette's arms are manipulated by strings, but Henson used rods to move his Muppets' arms, allowing greater control of expression. Additionally, he wanted the Muppet characters to "speak" more creatively than was possible for previous puppets, which had random mouth movements, so he used precise mouth movements to match the dialogue; when Henson began work on Sam and Friends, he asked fellow University of Maryland senior Jane Nebel to assist him. The show was a financial success, but after graduating from college, he began to have doubts about going into a career performing with puppets.
He spent several months in Europe, where he was inspired by European puppet performers who looked on their work as an art form. Jane and he began dating after his return to the United States. Despite the success of Sam and Friends, Henson spent much of the next two decades working in commercials, talk shows, children's projects before being able to realize his dream of the Muppets as "entertainment for everybody"; the popularity of his work on Sam and Friends in the late 1950s led to a series of guest appearances on network talk and variety shows. Henson himself appeared as a guest on many shows, including The Steve Allen Show, The Jack Paar Program, The Ed Sullivan Show; this first national television broadcast increased exposure, which led to hundreds of commercial appearances by Henson characters throughout the'60s. Among the most popular of Henson's commercials was a series for the local Wilkins Coffee company in Washington, DC, in which his Muppets were able to get away with a greater level of slapstick violence than might have been acceptable with human actors and would find its way into many
Service robots assist human beings by performing a job, dirty, distant, dangerous or repetitive, including household chores. They are autonomous and/or operated by a built-in control system, with manual override options; the term "service robot" does not have a strict technical definition. The International Organization for Standardization defines a “service robot” as a robot “that performs useful tasks for humans or equipment excluding industrial automation applications”. According to ISO 8373 robots require “a degree of autonomy”, the “ability to perform intended tasks based on current state and sensing, without human intervention”. For service robots this ranges from partial autonomy - including human robot interaction - to full autonomy - without active human robot intervention; the International Federation of Robotics statistics for service robots therefore include systems based on some degree of human robot interaction or full tele-operation as well as autonomous systems. Service robots are categorized according to professional use.
They have many structures as well as application areas. The possible applications of robots to assist in human chores is widespread. At present there are a few main categories. Industrial service robots can be used to carry out simple tasks, such as examining welding, as well as more complex, harsh-environment tasks, such as aiding in the dismantling of nuclear power stations. Industrial robots have been defined by the International Federation of Robotics as "an automatically controlled, multipurpose manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications". Service robots are system-based autonomous and adaptable interfaces that interact and deliver service to an organization’s customers. Domestic robots perform tasks that humans perform in non-industrial environments, like people's homes such as for cleaning floors, mowing the lawn and pool maintenance. People with disabilities, as well as people who are older, may soon be able to use service robots to help them live independently.
It is possible to use certain robots as assistants or butlers. Robotic systems perform many functions such as repetitive tasks performed in research; these range from the multiple repetitive tasks made by gene samplers and sequencers, to systems which can replace the scientist in designing and running experiments, analysing data and forming hypotheses. The ADAM at the University of Aberystwyth in Wales can " logical assumptions based on information programmed into it about yeast metabolism and the way proteins and genes work in other species, it set about proving that its predictions were correct."Autonomous scientific robots perform tasks which humans would find difficult or impossible, from the deep sea to outer space. The Woods Hole Sentry can descend to 4,500 metres and allows a higher payload as it does not need a support ship or the oxygen and other facilities demanded by human piloted vessels. Robots in space include the Mars rovers which could carry out sampling and photography in the harsh environment of the atmosphere on Mars.
Event Robots Event Robots are starting to be used within the realms of service Robots to engage with clients and event attendees. Robots provide a great source of interaction. “Eva” photography Robot is a great example of how a Robot can be used for events to engage attendees. Domestic robot Home automation for the elderly and disabled Personal robot Robot kit Social robot Photography Robot Lists of types of robots Haidegger T, Barreto M, Goncalves P, Habib MK, Ragavan SKV, Li H et al Applied ontologies and standards for service robots. Robotics Autonomous Systems 61, 1215–1223. Sprenger M, Mettler T Service Robots, Business & Information Systems Engineering, 57, 271–274. Jochen Wirtz, Paul Patterson, Werner Kunz, Thorsten Gruber, Vinh Nhat Lu, Stefanie Paluch, Antje Martins, “Brave New World: Service Robots in the Frontline”, Journal of Service Management, Vol. 29, No. 5, 907-931, https://doi.org/10.1108/JOSM-04-2018-0119
A six-legged walking robot should not be confused with a Stewart platform, a kind of parallel manipulator used in robotics applications. A hexapod robot is a mechanical vehicle. Since a robot can be statically stable on three or more legs, a hexapod robot has a great deal of flexibility in how it can move. If legs become disabled, the robot may still be able to walk. Furthermore, not all of the robot's legs are needed for stability. Many hexapod robots are biologically inspired by Hexapoda locomotion. Hexapods may be used to test biological theories about insect locomotion, motor control, neurobiology. Hexapod designs vary in leg arrangement. Insect-inspired robots are laterally symmetric, such as the RiSE robot at Carnegie Mellon. A radially symmetric hexapod is ATHLETE robot at JPL. Individual legs range from two to six degrees of freedom. Hexapod feet are pointed, but can be tipped with adhesive material to help climb walls or wheels so the robot can drive when the ground is flat. Most hexapods are controlled by gaits, which allow the robot to move forward and side-step.
Some of the most common gaits are as follows: Alternating tripod: 3 legs on the ground at a time. Quadruped. Crawl: move just one leg at a time. Gaits for hexapods are stable in rocky and uneven terrain. Motion may be nongaited, which means the sequence of leg motions is not fixed, but rather chosen by the computer in response to the sensed environment; this may be most helpful in rocky terrain, but existing techniques for motion planning are computationally expensive. Insects are chosen as models. Complex behaviours can be attributed to just a few neurons and the pathway between sensory input and motor output is shorter. Insects' walking behaviour and neural architecture are used to improve robot locomotion. Conversely, biologists can use hexapod robots for testing different hypotheses. Biologically inspired hexapod robots depend on the insect species used as a model; the cockroach and the stick insect are the two most used insect species. At present no complete nervous system is known, models combine different insect models, including those of other insects.
Insect gaits are obtained by two approaches: the centralized and the decentralized control architectures. Centralized controllers directly specify transitions of all legs, whereas in decentralized architectures, six nodes are connected in a parallel network. Hexbug Stiquito Rhex Whegs LAURON Vorpal The Hexapod Biomechanics Insects Mondo spider Robotics Robot locomotion Stewart platform Poly-pedal Laboratory at Berkeley. Biological Cybernetics/Theoretical Biology