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Robotics- Naved
- 1. KHWAJA NAVED EC-0842231409Introduction to Robotics
- 2. Definition of aRobot Definition of a Robot According to The Robot Institute of America (1979) : "A reprogrammable, multifunctional manipulator designed to move materials, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks." According to the Webster dictionary: "An automatic device that performs functions normally ascribed to humans or a machine in the form of a human (Webster, 1993)."
- 3. A Brief Historyof Robotics Robotics' history is tied to so many other technological advances that today seem so trivial, we don't even think of them as robots. How did a remote-controlled boat lead to autonomous metal puppies?
- 4. Nikola Tesla Croatian-Americanscientist Nikola Tesla. Invented many things, including the alternating current system. Remote-controlled, submersible boat was acting on radio signals.
- 5. Slaves of steelThe first person to use the word robot was a playwright, Czechoslovakian writer Karel Capek first used the word robot in his satirical play, R.U.R. (Rossum's Universal Robots). Cover page of the first edition
- 6. Wartime inventions World War II was a big catalyst in the development of two important robot components: artificial sensing and autonomous control. The U.S. military created auto-control systems for mine detectors that would sit in front of a tank as it crossed enemy lines The Germans developed guided robotic bombs that were capable of correcting their trajectory. German robot bomb found in France
- 7. A robot inevery pot The invention of the transistor in 1948 increased the rate of electronic growth and the possibilities seemed endless. The creation of silicon microchips reinforced that growth. The seven-foot robot could smoke and play the piano. Elecktro:The smoking robot
- 8. Industrial-strength arms 1961 General Motors installed the applied telecherics system on their assembly line. The one-armed robot unloaded die casts, cooled components and delivered them to a trim press. In 1978 the PUMA (Programmable Universal Machine for Assembly) was introduced and quickly became the standard for commercial telecherics. PUMA industrial robot
- 9. Early personal robots RB5X Hero 1
- 10. Surgical tools In1985 Dr. Yik San Kwoh invented the robot-software interface used in the first robot-aided surgery, a stereo tactic procedure. The surgery involves a small probe that travels into the skull. A CT scanner is used to give a 3D picture of the brain, so that the robot can plot the best path to the tumor. Dr. Yik San Kwoh with surgical robot
- 11. Hazardous duties DanteII aids in the dangerous recovery of volcanic gases and samples. These robotic arms with wheels saved countless lives defusing bombs and investigating nuclear accident sites. Telecheric robot inspects suspicious package
- 12. Solar-powered insects Mark Tilden's BEAM robots look and act like big bugs. Tilden builds simple robots out of discrete components and shies away from the integrated circuits most other robots use for intelligence. Started in the early 1990s, the idea was to create inexpensive, solar-powered robots ideal for dangerous missions such as landmine detection.
- 13. A range ofrovers Sojourner, semi-autonomous robot platforms to be launched into Mars in 1996. The problem was, it could only travel short distances. In 2004, twin robot rovers caught the public's imagination again, sending back amazing images in journeys of kilometers, not meters. Mars rover
- 14. Entertaining pets Inthe late '90s there was a return to consumer-oriented robots. One of the real robotic wonders of the late '90s was AIBO the robotic dog, made by Sony Corp. By using sensor array, AIBO can autonomously navigate a room and play ball. AIBO takes a spill
- 15. Quasi 2005 –Los Angeles Quasi can make responses based on guest input and can recognize speech patterns, track faces, detect proximity, dispense candy and even perform a karaoke duet. Softwares includes Alias Maya, BAT and so on. Quasi - Carnegie Mellon University
- 16. Classification Of RobotsROBOTS Robot like devices: Prostheses Exoskeletons Telecherics Coordinate system based robots: Cylindrical Spherical Cartesian Human like robots: Humanoids, Androids, Actroids, Geminoids,Gynoids
- 17. Robot like devices: Prostheses: The figure, showing a prosthetic arm actuated by artificial muscles and fit to a human, describes the long-term goals of this research in which the patient will be able to control a multi-degree of freedom robot prosthesis that provides force feedback information.
- 18. Exoskeletons: Exoskeletons area skeletal framework to be worn by a human, specially soldiers and construction workers. They are designed to assist and protect the wearer.
- 19. Telecherics/Telerobotics: Telerobotics is the area of robotics concerned with the control of robots from a distance, chiefly using wireless connections (like Wi-Fi, Bluetooth) or tethered connections. The figure alongside shows a mars rover.
- 20. Robots based oncoordinate system:
- 21. Practical robots basedon coordinate system:
- 22. Human like robots: Humanoid Android
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- 29. Sense organs inrobots(The sensors): SENSORS Tactile sensors Proximity and range sensors Sensor based systems
- 30. Tactile sensors: PIE-ZO ELECTRIC SENSORS RESISTIVE SENSORS TACTILE ARRAY SENSORS TOUCH SENSORS FORCE SENSORS TACTILE SENSORS
- 31. Proximity sensors: INDUCTIVESENSORS CAPACITIVE SENSORS HALL EFFECT SENSORS OPTICAL PROXIMITY SENSORS PROXIMITY SENSORS
- 32. Evolutionary Algorithm: CharlesDarwin first identified the process of natural selection in his monumental work “ The Origin of Species”. Inspired by this natural process of ‘survival of the fittest’, evolutionary algorithms (EAs) attempt to find a solution to a problem using simulated evolution in a computer.
- 33. Types of EAs:There are two types of EAs: Genetic Algo (GA): It involves manipulating a fixed-length bit string. The bit string represents a solution to the problem being solved; it is up to the programmer to determine the meaning of the string.
- 34. Genetic Programming (GP): It involves generating expression trees as used by languages such as LISP and SCHEME. With genetic programming, actual programs can be created and then executed.
- 35. Applying EAs toRobotic Navigation EAs have been used to get a robot to learn how to adapt to its limited capabilities. Using GP in this way is termed evolutionary learning. In most of the EA applications, two distinct steps occur: an initial training period is conducted by running the EA on a training set, followed by the execution of the best-fit solution.
- 36. With Continuousand Embedded Learning , the two steps are linked and operated concurrently while the robot is performing its task. The figure shows an outline of this approach where the key components are: Learning continues indefinitely, allowing adaptation to sensory failure. Learning is done on a simulation model. The simulation model is updated to reflect changes in the real robot or environment
- 37. In an experiment,a robot was given the task of navigating to the opposite side of a room through a passage in a wall starting from one wall and heading in a random direction from -90 degrees to 90 degrees, with 0 pointing directly to the opposite wall.
- 38. With no evolutionand all sensors functioning, the robot was able to navigate successfully about 25% of the time. After 50 generations of evolution, the robot's success rate increased to about 61%. With three sensors on the right side of the robot disabled after 50 generations, the success rate dropped to about 42%, but increased over 50 more generations to about 63%. The results of the experiment show that a robot using CEL can not only learn how to improve its navigation abilities by itself, but also re-learn how to navigate after suffering the loss of some sensory capability
- 39. Living on TheirOwn: Ecosystem-like settings are interesting from an alife perspective. Within ecosystems, the main goal of a robot is self-preservation. Resources, especially energy, are limited in time and space. Consequently, robots must compete for them. Thus competition forms the basis of all robot interactions in the system.
- 40. Biological Inspiration: Whentrying to re-create biological phenomena, it makes sense to look at the biological world for some good initial pointers. For instance, the study of robotic locomotion is aided by observing and imitating biological systems such as a spider. A robot is limited when using wheels (very un-biological) in rough terrains, whereas a biologically inspired robot would have legs like that of a spider for maneuvering around and over obstacles
- 41. Implementation of knowledge:Line following robot: Line follower is a machine that can follow a path. The path can be visible like a black line on a white surface (or vice-versa) or it can be invisible like a magnetic field. Practical applications of a line follower involve automated cars running on roads with embedded magnets; guidance system for industrial robots moving on shop floor etc.
- 42. Schematic Of aLine Follower:
- 43. References: http://www.robotics.utexas.edu/rrg/learn_more/history/ http://www.msnbc.com/modules/robot_history/http://www.thelightningguy.com/tesla.htm http://www.honda.co.jp/robot/movie/ http://www.cooltoolawards.com/hardware/Humanoid.htm http://www.ed.ams.eng.osaka-u.ac.jp/development/Humanoid/ReplieeQ2/ReplieeQ2_eng.htm http://www.motionanalysis.com/applications/movement/sports/hawksystem.html http://www.instructibles.com http://www.aibotix.com
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Editor's Notes
- #4 Our fascination with robots began more than 100 years ago. Looking back, it's easy to get confused about what is and is not a robot. Robotics' history is tied to so many other technological advances that today seem so trivial, we don't even think of them as robots. How did a remote-controlled boat lead to autonomous metal puppies?
- #5 Tesla's submersible Croatian-American scientist Nikola Tesla invented many things, including the alternating current system we use for power today. But Tesla was an eccentric scientist who talked about interplanetary communication, and his experiments were far ahead of their time. The common man had never even heard of radio in 1897. So Tesla's remote-controlled, submersible boat left many people thinking he must have stuck a midget in the hull. They were wrong -- the boat really was acting on radio signals.
- #6 The first person to use the word robot wasn't a scientist, but a playwright. Czechoslovakian writer Karel Capek first used the word robot in his satirical play, R.U.R. (Rossum's Universal Robots). Taken from the Czech word for forced labor, the word was used to describe electronic servants who turn on their masters when given emotions. This was only the beginning of the bad-mouthing robots would receive for the next couple of decades. Many people feared that machines would resent their role as slaves or use their steely strength to overthrow humanity.
- #7 World War II was a big catalyst in the development of two important robot components: artificial sensing and autonomous control. Radar was essential for tracking the enemy. The U.S. military also created auto-control systems for mine detectors that would sit in front of a tank as it crossed enemy lines. If a mine was detected, the control system would automatically stop the tank before it reached the mine. The Germans developed guided robotic bombs that were capable of correcting their trajectory.
- #8 For robotics, the '40s and '50s were full of over-the-top ideas. The invention of the transistor in 1948 increased the rate of electronic growth and the possibilities seemed endless. Ten years later, the creation of silicon microchips reinforced that growth. The Westinghouse robot Elecktro showed how far science and imagination could go. The seven-foot robot could smoke and play the piano. Ads from the era suggest that every household would soon have a robot.
- #9 As the demand for cars grew, manufacturers looked for new ways to increase the efficiency of the assembly line through telecherics. This new field focused on robots that mimicked the operator's movements from a distance. In 1961 General Motors installed the applied telecherics system on their assembly line. The one-armed robot unloaded die casts, cooled components and delivered them to a trim press. In 1978 the PUMA (Programmable Universal Machine for Assembly) was introduced and quickly became the standard for commercial telecherics.
- #10 With the rise of the personal computer came the personal robot craze of the early '80s. The popularity of Star Wars didn't hurt either. The first personal robots looked like R2D2. The RB5X and the HERO 1 robots were both designed as education tools for learning about computers. The HERO 1 featured light, sound and sonar sensors, a rotating head and, for its time, a powerful microprocessor. But the robots had a lighter side too. In demo mode, HERO 1 would sing. The RB5X even attempted to vacuum, but had problems with obstacles.
- #11 While robots haven't replaced doctors, they are performing many surgical tasks. In 1985 Dr. Yik San Kwoh invented the robot-software interface used in the first robot-aided surgery, a stereo tactic procedure. The surgery involves a small probe that that travels into the skull. A CT scanner is used to give a 3D picture of the brain, so that the robot can plot the best path to the tumor. The PUMA robots that are commonly used learn the difference between healthy and diseased tissue, using tofu for practice.
- #12 As scientific knowledge grew so did the level of questioning. And, as with space exploration, finding the answers could be dangerous. In 1994 the CMU Field Robotics Center sent Dante II, a tethered walking robot to explore Mt. Spurr in Alaska. Dante II aids in the dangerous recovery of volcanic gases and samples. These robotic arms with wheels (a.k.a. mobile applied telecherics) saved countless lives defusing bombs and investigating nuclear accident sites. The range of self-control, or autonomy, on these robots varies.
- #13 Some robots mimic the humans, while others resemble lower life forms. Mark Tilden's BEAM robots look and act like big bugs. The name BEAM is an acronym for Tilden's philosophy: biology, electronics, aesthetics, and mechanics. Tilden builds simple robots out of discrete components and shies away from the integrated circuits most other robots use for intelligence. Started in the early 1990s, the idea was to create inexpensive, solar-powered robots ideal for dangerous missions such as landmine detection.
- #14 By the 1990s NASA was looking for something to regain the public's enthusiasm for the space program. The answer was rovers. The first of these small, semi-autonomous robot platforms to be launched into space was the Sojourner, sent to Mars in 1996. Its mission involved testing soil composition, wind speed and water vapor quantities. The problem was, it could only travel short distances. NASA went back to work. In 2004, twin robot rovers caught the public's imagination again , sending back amazing images in journeys of kilometers, not meters.
- #15 In the late '90s there was a return to consumer-oriented robots. The proliferation of the Internet also allowed a wider audience to get excited about robotics, controlling small rovers via the Web or buying kits online. One of the real robotic wonders of the late '90s was AIBO the robotic dog, made by Sony Corp. Using his sensor array, AIBO can autonomously navigate a room and play ball. Even with a price tag of over $2,000, it took less than four days for AIBO to sell out online. Other "pet robots" followed AIBO, but the challenge of keeping the pet smart and the price low remains.
- #16 Quasi can make responses based on guest input and can recognize speech patterns, track faces, detect proximity, dispense candy and even perform a karaoke duet. The software used to create interactive experiences with Quasi consists of both off-the-shelf multimedia applications as well as custom-created authoring tools. Alias Maya, a 3D modeling and animation package is used to create all of Quasi's movements. The custom Behavior Authoring Tool (BAT) allows someone with little to no programming experience to create rich, complex character personalities for Quasi.
- #18 In medicine , a prosthesis or prosthetic limb is an artificial device extension that replaces a missing body part. It is part of the field of biomechatronics , the science of using mechanical devices with human muscle, skeleton, and nervous systems to assist or enhance motor control lost by trauma, disease, or defect. Prostheses are typically used to replace parts lost by injury ( traumatic ) or missing from birth ( congenital ) or to supplement defective body parts. The artificial limbs described here, patterned after human anatomy, are designed to be lightweight, compact and dexterous, while maintaining a high lifting capability. The patient uses visual and haptic signals to control the prosthesis with electromyographic (EMG) signals Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles . EMG is performed using an instrument called an electromyograph , to produce a record called an electromyogram . An electromyograph detects the electrical potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect medical abnormalities and activation level of human or animal.
- #19 A powered exoskeleton , also known as powered armor is a powered mobile machine consisting primarily of an exoskeleton-like framework worn by a person and a power supply that supplies at least part of the activation-energy for limb movement. Powered exoskeletons are designed to assist and protect the wearer. They may be designed, for example, to assist and protect soldiers and construction workers, or to aid the survival of people in other dangerous environments
- #20 Telerobotics is the area of robotics concerned with the control of robots from a distance, chiefly using wireless connections (like Wi-Fi, Bluetooth) or tethered connections. Most space-based astronomy has been conducted with telerobotic telescopes. Recent noteworthy examples include the Mars exploration rovers (MER) and the Hubble Space Telescope . In the case of the MER mission, the spacecraft and the rover were each telerobotically operated. The International Space Station (ISS) uses a two armed telemanipulator called Dextre . Marine remotely operated vehicles (ROVs) are widely used to work in water too deep or too dangerous for divers. They repair offshore oil platforms and attach cables to sunken ships to hoist them. They are usually attached by a tether to a control center on a surface ship. The wreck of the Titanic was explored by an ROV, as well as by a crew-operated vessel. Remote manipulators are used to handle radioactive materials.
- #21 The first type of robot is called the Cartesian robot. This type of robot uses the X, Y, Z three dimensional coordinate system to control movement and location. It is used for pick and place work, application of sealant, assembly operations, handling machine tools and arc welding. It's a robot whose arm has three prismatic joints, whose axes are coincident with the Cartesian coordinates. Gantry robots are Cartesian robots that have been super-sized! This structure minimizes deflection along each axis. Cylindrical robots have a main axis that is in the centre of the operating envelope. It can reach into tight areas without sacrificing speed or repeatability. It is used for assembly operations, handling at machine tools, spot welding, and handling at die casting machines. It's a robot whose axes form a cylindrical coordinate system. Spherical or polar robots are similar to a cylindrical robot, but form a spherical range of motion using a polar coordinate system. It is u sed for handling at machine tools, spot welding, die casting, fettling machines, gas welding and arc welding. It's a robot whose axes form a polar coordinate system.
- #22 The robots shown above are scara and articulated hand robots which are a combination of spherical and cylindrical coordinate robots. SCARA robot : Used for pick and place work, application of sealant, assembly operations and handling machine tools. It's a robot which has two parallel rotary joints to provide compliance in a plane. Articulated robot : Used for assembly operations, die casting, fettling machines, gas welding, arc welding and spray painting. It's a robot whose arm has at least three rotary joints.
- #23 There is a new category of robot called “Geminoid”. A Geminoid is a tele- operated android of an existent person. Androids are test beds for studying human-robot interaction. They enable us to compare the developed robot technologies and humans in a direct manner. Androids have been used for verifying cognitive and psychological hypotheses. The tight connection between robotics and cognitive science is referred to as android science. The developed androids so far are not enough for various cognitive tests, they lack abilities for long-term conversation. In order to compensate this problem, we need to consider high-bride systems in which a human and android are integrated. This is where the new development in Geminoid comes to play. By using the geminoid, scientists can tackle the unsolved problems and extend the framework of android science.
- #24 The team which created the Honda Humanoid robot took a lesson from our own bodies to build this two-legged robot. When they began in 1986, the idea was to create an intelligent robot that could get around in a human world, move on stairs, carpeting and other tough terrains. Getting a single robot mobile in a variety of environments had always been a challenge. But by studying feet and legs, the Honda team created a robot capable of climbing stairs, kicking a ball, pushing a cart, or tightening a screw. The latest version of ASIMO (Advanced Step in Innovative Mobility) has 34 degrees of freedom to perform various motions.
- #25 ASIMO: Robots are not only the subject of science fiction nowadays. They are being, slowly, but surely, introduced into all spheres of life. Androids humanoids are, probably, the most interesting type of robots. Since the idea of a robot appeared in science fiction, engineers and designers wanted to build a robot that would be able to move like a human. ASIMO Honda ASIMO is one of the most popular robots today. This humanoid has survived four modifications within 13 years. The latest ASIMO P4 can study the environment, understand human speech, browse the internet and find useful information and latest news. It may have some other unexpected abilities as well which are yet to be explored.
- #28 The uncanny valley is a hypothesis regarding the field of robotics. The hypothesis holds that when roboots and other facsimiles of humans look and act almost like actual humans, it causes a response of revulsion among human observers. The term was coined by a roboticist Masahiro Mori . Mori's hypothesis states that as a robot is made more humanlike in its appearance and motion, the emotional response from a human being to the robot will become increasingly positive and empathic , until a point is reached beyond which the response quickly becomes that of strong revulsion. However, as the appearance and motion continue to become less distinguishable from a human being, the emotional response becomes positive once more and approaches human-to-human empathy levels.
- #29 Degrees of Freedom refer to the movement range available for a given piece of equipment within three dimensions. The six degrees of a rigid body are often described using nautical terms: Moving up and down (heaving); Moving left and right (swaying); Moving forward and backward (surging); Tilting forward and backward (pitching); Turning left and right (yawing); Tilting side to side (rolling).
- #31 The sensors which sense contact between an object and themselves are called tactile sensors. Tactile sensors can be classified as: Touch sensors : This is the detection and measurement of a contact force at a defined point. A touch sensor can also be restricted to binary information, namely touch, and no touch. Force sensors : Capacity to measure forces permits the robots to perform a number of tasks. Force sensing in robotics can be accomplished in several ways. A commonly used technique is “force-sensing wrist”. This consists of a special load-cell mounted between the gripper and the wrist. Another technique is to measure the torque being exerted by each joint; this is usually accomplished by sensing motor current for each of the joint motors. Tactile array sensors : A tactile array sensor is a special type of force sensor composed of a matrix of force sensing elements. The force data provided by this type of device may be combined with pattern recognition to describe a number of characteristics about the impression contacting the array sensor surface. Among these characteristics are (1.) The presence of an object (2.) The objects contact area, shape, location and orientation, (3.) The pressure and pressure distribution and (4.) Force magnitude and location. Resistive sensors : The use of compliant materials that have a defined force-resistance characteristics have received considerable attention in touch and tactile sensor research. The basic principle of this type of sensor is the measurement of the resistance of a conductive elastomer or foam between two points. The majority of the sensors use an elastomer that consists of a carbon doped rubber. Pie-Zo electric sensors : Polymeric materials that exhibit piezoelectric properties are suitable for use as a touch or tactile sensors, while quartz and some ceramics have piezoelectric properties, polymers such as polyvinylidene fluoride (PVDF) are normally used in sensors.
- #32 Proximity sensors are one which are used in robotics for the near-field work in connection with object grasping or avoidance. The proximity sensors are further classified as: Inductive sensors: Sensors based on the change of inductance due to the presence of metallic object are among the most widely used industrial proximity sensors. The effect of bringing the sensor in close proximity to a ferromagnetic material causes a change in position of the permanent magnet. Capacitive sensors: Capacitive sensors are potentially capable of detecting all solid and liquid materials. These sensors are based on detecting a change in capacitance induced by a surface that is brought near the sensing element. The sensing element is a capacitor composed of sensitive electrode and a reference electrode. Hall effect/Magnetic sensors: Hall effect sensors are based on the principle of Lorentz force which acts on a charged particle through a magnetic field. This force acts on a charged particle traveling through a magnetic field whose axis is perpendicular to the plane established by the direction of motion of the charged particle and the direction of the field. Bringing ferromagnetic material close to the semiconductor-magnet device would decrease the strength of the magnetic field, thus reducing the Lorentz force and ultimately, the voltage across the semiconductor. This drop in voltage is the key for sensing proximity with Hall-effect sensors. Optical proximity sensors: This sensor consists of a solid-state light emitting diode (LED), which acts as a transmitter of infrared light, and a solid state photodiode which acts as the receiver. The cones of light formed by focusing the source and the detector on the same plane intersect in a long, pencil like volume. This volume defines the field of operation of the sensor since a reflective surface which intersects the volume is illuminated by the source and simultaneously “seen” by the receiver. Voice sensors: Voice sensing relies on the techniques of speech recognition to analyze spoken words uttered by a human being and compare those words with a set of stored word patterns. When the spoken word matches the stored word pattern, this indicates that the robot should perform some particular actions which correspond to the word or series of words.
- #33 Certain characteristics that govern an individual's chances of survival are passed to offspring during reproduction. Individuals with poor characteristics die off, making the species stronger in general. Evolutionary Algorithm: There are two related, yet distinct, types of EAs. The first type, genetic algorithms (GAs) , involves manipulating a fixed-length bit string. The bit string represents a solution to the problem being solved; it is up to the programmer to determine the meaning of the string. The second, genetic programming , involves generating expression trees as used by languages such as LISP and SCHEME . With genetic programming, actual programs can be created and then executed.
- #34 Generally speaking, the process used in evolutionary learning begins by randomly generating a population of individuals where each individual is a potential solution to the problem. The population is the set of individuals generated. Each individual contains a genome, the content produced during the execution of EAs. In the case of GAs, the fixed-length bit string is the genome. Next, each individual in the population is evaluated using a fitness function. Fitness functions use a method of testing solution quality for the respective problem domain. How the fitness of an individual is used depends on the implementation of the evolutionary algorithm. Usually, a higher fitness value corresponds to a greater chance of the individual being selected for reproduction. Different methods of producing the next generation exist, but most commonly, two operators are employed: mutation and breeding . Mutation involves randomly altering one or more genes in an individual's genome. Breeding uses a crossover operation to combine components of two parents' genomes to produce one or more children. Once a new generation is created, the old one is discarded.
- #35 Here the solutions are in the form of computer programs, and their fitness is determined by their ability to solve a computational problem. Lisp (or LISP ) is a family of computer programming languages with a long history and a distinctive, fully parenthesized syntax. Originally specified in 1958, Lisp is the second-oldest high-level programming language in widespread use today. The name LISP derives from "List Processing". Lisp has pioneered many ideas in computer science , including tree data structures , automatic storage management , dynamic typing , and the self-hosting compiler . The interchangeability of code and data also gives Lisp its instantly recognizable syntax. A function call or syntactic form is written as a list with the function or operator's name first, and the arguments following; for instance, a function f that takes three arguments might be called using (f arg1 arg2 arg3).
- #38 A Nomadic Technologies Nomad 200 Mobile Robot was used for the real-world tests. The robot is a three wheeled synchronized-steering unit that features seven front-mounted sonar units. The monitor in the execution system combines the output of sensors with information about the robot's actuator execution to determine sensor failures. If a frontal sonar unit continuously outputs zero as the distance from the robot to an obstacle but the robot keeps moving forward, then that sensor is marked as having failed. In the experiment, sonar "failure" was simulated by covering the sensor with a hard material. The initial rule-set used in the experiment gave the robot a basic notion of how to get to the other side of the room, but did not take into account obstacles or walls. The simulation model initially assumed all sensors were working.
- #40 The basic ecosystem located at the Flemish Free University of Brussels (VUB) is a 5 m X 3 m space enclosed by walls. Initially it includes simple mobile robots, the moles . The photo sensors, positioned at the front of the robot, are used to navigate and to find objects in the ecosystem. The arena also contains a charging station, where the robots can autonomously recharge their batteries. The robots drive into the charging stations and make contact with conductive plates that connect them to the energy source. This electrical energy is food for robots. The robots constantly monitor their energy level and in this way know when they are hungry. The robots' whole world revolves around earning and competing for the electrical food. There is a limited amount of food in the ecosystem. Also, the ecosystem contains competitors: small boxes that house lamps emitting a modulated light. These lamps are connected to the same global energy-source as the charging station; they therefore feed on the same source as the robots. The robots must knock out the competitors.
- #41 An example may be regarding how a spider-like robot that loses a leg might adjust its gait to complete a mission-critical task. One can look at an experiment performed as an example. Here two legs from opposite sides of a spider were amputated. Two possibilities existed for the spider: it could either retain a diagonal rhythm of locomotion using four legs, but lose its ability to balance; or it could move three legs at a time, offsetting its diagonal rhythm. The experiment showed that the spider chose the second alternative, which was more mechanically stable. This apparently has to do with the fact that although the walking patterns are determined in the spiders “central oscillator,” they can be modified by feedback from sensory organs in the legs. In effect, the spider adapted by reprogramming itself.
- #42 The line following robot will need to see the line, therefore we require a light detector of some sort. We also would like it if the line following robot could do this regardless of the ambient conditions (is the room dark or light? is it lit by sunlight or artificial light?). So the robot will also need its own illumination source. The weapon of choice here will be Infra Red (IR) light. To make this easy for ourselves the light only needs to be constant... if a white line is present then it will reflect a lot of IR from our source. If the line is black then we see the opposite effect.
- #43 The schematic of a line following robot shows a block of various sensors which sense accordingly and provide analog signals which are converted by the comparator into binary data provided to the microcontroller which is the brain representative of this robot. The motor driver drives the two motors accordingly and the robot moves in the specified straight direction. Use of a microcontroller enables the robot to re-track the lost path.