Comp.robotics FAQ

Comp.robotics FAQ July, 2003 [No Changes Since June, 2003]
** Table of Contents **
1 About this FAQ 1.1. Purpose 1.2. All the fun legal stuff: copyright, usage, history, and disclaimers.
1.3. Additions, submissions, and questions 1.4. Thanks and special thanks.
2 Introduction: What are robots? 2.1 So, what is a robot? robotics? roboticist? Does anyone know what they are talking about? 2.2 Origin of the word: Rossum's Universal Robots 2.3 What is the growth rate of robotics? How many robot critters of each type are out there anyway?
3 A vocabulary for describing robots: gizbots and simbots and flightbots, oh my! 3.1 Summary and usage 3.2 How Modular Is Your 'bot: Gizbots, Morphbots, and Unibots 3.3 Where does your 'bot live? Stationbots, Floorbots, Terrainbots, and the Envirobots of air, sea, and space. 3.6 How independent is your 'bot: Autobot, Taskbot, RCbot, and Telebot Controls 3.4 How big is your 'bot: Microbot, Macrobot, and Megabot Sizes 3.5 How real is your 'bot: Thoughtbot, Fantasybot, Simbot, Tinkerbot, and Workbot Development Phases
4 Getting started - Joining the People of Robotics 4.1 Watching the art: surveying robotics 4.2 A most enjoyable hobby: building your own robots 4.3 Studying for a living: universities and research 4.4 Working for a living: the robotics industry
5 Using the Newsgroups 5.1 Which newsgroup should I use? 5.2 How should I ask a good question of the community? 5.3 How do I answer a question for the community? 5.4 Robots thinking, learning, and dreaming
1 About this FAQ
1.1. Purpose
Every Frequently Asked Questions document (FAQ) hopes to answer some of the frequently asked questions and to provide some framework of knowledge to people new in the field. The hope is that the FAQ will have enough new information to justify taking your time to read it. Also, this FAQ may provide a framework of robotics knowledge and some pointers for you to find your own answers through research, reading, and experience.
1.2. All the fun legal stuff: copyright, usage, history, and disclaimers.
This document copyright 2001, 2002, 2003 by Charles Merriam. This FAQ was written from scratch in 2001 and should be updated every three months. You may mirror this document for noncommercial use. If you are reading this copy on a CD-ROM, then it is probably out of date. You can find a copy of the current FAQ at . If you are at all confused about using or distributing the FAQ, just contact Charles at This document is unrelated to an older comp.robotics FAQ maintained until 1996 by Kevin Dowling, then of Carnegie Mellon University. This older FAQ can be found at
The information in this FAQ is probably accurate but not guaranteed. Use at your own risk and watch for the occasional bad pun.
1.3. Additions, submissions, and questions
Both the questions and the answers in this FAQ will change over time. I will have made mistakes and omissions, and the field of robotics will continue to mature. I appreciate your help in identifying errors I made in this FAQ and for bringing up new information. Please send all comments, submissions and glamorous resources to Charles at, and please put the section number in the header line. I'll try to integrate in all corrections, some new resources, and additional details into each new version. Also, if you are willing to be on the 'proof-reading' list, let me know.
Feedback on the FAQ is greatly appreciated. I expect to add another section looking at the core systems a robot: sensors, manipulators, controls and intelligences, and chassis. If you feel there is another core area, please let me know.
Finally, some writers of FAQs dedicate time to answer every question emailed to them. I ask that questions be posted the comp.robotics.misc and comp.robotics.research newsgroup for answering, as they were before the FAQ.
1.4. Thanks and special thanks.
Many people will be open and helpful in improving this FAQ, and I hope to give credit to as many as possible. For now, let me give a special thanks to my wife, Judith, for the ideas, proof reading, and patience that allowed me to write this document.
Also, thanks to Bill Benson and Wayne Gramlich of the Robobricks project for edits and suggestions.
2 Introduction: What are robots?
2.1 So, what is a robot? robotics? roboticist? Does anyone know what they are talking about?
There are many definitions for robot, meaning that there is none.
I define a robot as a computer that moves outside molecules.
Webster's defines a robot as a machine that looks like a human and performs various complex tasks. Alternatively, Webster's also defines a robot as a device that automatically performs complicated, often repetitive tasks. Various robotics books define robots as machines that move, respond to stimuli, run programs, or mimic life. Some computer books define robots as computer programs that simulate a human user for other computer programs. Finally, some people with thick Boston accents define robots as oar driven water vehicles.
Almost every book feels it important to spend a couple of pages defining an exact meaning for the term robot in the context of the book. Some define robots by required components; e.g., moving parts and computation. Some define by function or philosophy, e.g., a machine that aspires to intelligence. This lets you know there isn't a single definition. You can start long arguments about the 'robot-ness' of 2001's HAL, Stiquito, BattleBots, BEAM robots, automobiles, humans, and garage door openers. You will find people who challenge your definitions and understanding in these discussions, and you will find people who try to convince you by bellowing. When in doubt, it is easiest to agree that everything is a robot and recognize that you, personally, are only interested in some robots.
Robotics is the study of robots. Robotics may be the broadest cross disciplinary subject. It integrates mechanical engineering, computer science, vision processing, electrical engineering, and some biology, psychology, and art. Advances in all of these other fields are instantiated as advances in robotics.
A roboticist is someone who builds or studies robots. Next time you meet a roboticist, ask how many robots he or she has built. The result may surprise you, and will certainly get them talking.
2.2 Origin of the word: Rossum's Universal Robots
In 1920, a Czech playwright named Karel Capek wrote a play named "Rossum's Universal Robots". His manufactured factory workers were biological drones, called 'robots'. The Czech term 'robot' means slave or drone. The robots in the story, of course, try to rebel and extinguish the human race. 'Robots' sounds better than 'automations', 'automatons' or 'androids' so the name stuck. You can read more about the play at Dr. Dennis Jerz's site, /.
The concept of robots as self-motivated creatures endured from this story. People generally assign robots names and genders and there is a rush to ascribe algorithms, glitches and unexpected behaviors as the emotions of some new life come alive. It's a powerful tendency.
The image of metal mechanical men came later; it is easy on the special effects budgets of movies to put someone in a shiny metal suit with flashing lights. Fictional robots are often workers gone amok and are always more capable than what's available; it's the nature of fiction.
2.3 What is the growth rate of robotics? How many robot critters of each type are out there anyway?
Robotics grows by about 30% per year, meaning the trend is that every year there will be nearly one third more roboticists and nearly one third more robots. The only formal census I've run across is the United Nations reporting at , which concentrates on the established industrial robotic market. Robotics growth concentrates in new applications. It would be an interesting graduate project to make a census and to chart the health and profitability of robotics companies over time.
3 A vocabulary for describing robots: gizbots and simbots and flightbots, oh my!
3.1 Summary and usage
Vocabulary is the starting point for any discussion and is especially necessary in the broad field of robotics. Interesting discussions between the scientists, engineers, designers, and artists involved robotics need a clear vocabulary. The vocabulary below describes the basic design choices of robots and facilitates a good discussion. For a new roboticist, reading these terms will provide an overview of the basic design categories for robots. These terms are a pretty good way to describe a robot in a single sentence.
Each term describes a design choice for a robot. Taken together, these terms will describe the robot's construction, environment, size, control system, and current phase of construction. For example, you may be tinkering with a tiny, terrain traveling, autonomous, modular robot. In a conversation, you might describe it as an autobot or a terrianbot as short hand for it's autonomous or terrain traveling aspect. This chart shows a quick reference to the terms.
MODULAR CONSTRUCTION Gizbot - Assembled from modular building blocks. Snapped together gizmos. Reconfigurable. Morphbot - Self modifying, shape changing, self reassembling. Unibot - Statically constructed. Hand assembled.
ENVIRONMENTS Stationbot - Stationary robot. Pedestal or arm robot. Floorbot - Travels on floors, building interiors, and nearly level surfaces. Terrainbot - Travels outside over unfriendly ground terrain, and navigates rocks. Envirobot - Works in a challenging environment, including air, water, and space.
SIZES Microbot - Under two inches. Microrobotics, nanorobotics. Macrobot - Bigger than a microbot, but easy for one person to handle. Under two feet in any direction. Megabot - Bigger than a macrobot. Larger than one person can carry. Large hobbyist robots, automated vehicles.
REALITY AND COMPLETION Thoughtbot - Robot that has not been, will not be, or cannot be built. A thought experiment. Fantasybot - An artistic representation of a thoughtbot. A robot for film, anime, or art. Simbot - Robot that exists in a simulation. Tinkerbot - A robot being constructed or constantly being tinkered with as research. Workbot - A robot used to do work or in commercial production. A completed robot in use.
CONTROL STRATEGIES Autobot - Autonomous control, completely self controlled robot. Taskbot - Handling set of tasks. Self controlled for some sequences. Telebot - Teleoperations robot. Provides sensing and action under remote control of operator. RCbot - Remote controlled robot. Provides action under control of operator. Groupbot - A member of a group of cooperative robots.
3.2 How Modular Is Your 'bot: Gizbots, Morphbots, and Unibots
Robots are assembled in radically different ways. Most robots are constructed like an automobile: they are a collection of parts joined more or less permanently into a usable machine. Some others are made from interchangeable parts that can be reassembled into other robots quickly. Finally, a few robots reconfigure themselves during operation.
A gizbot is a robot assembled completely from modules or gizmos. Gizbots snap together using only screws or other temporary fasteners. The same parts can usually be taken apart and assembled into new robots by a competent roboticist or innovative six-year-old. Lego Mindstorms is a good example of a gizbot building kit, and allows you to build robots from gizmos including bricks, motors, wheels, and belts. See for more information on Lego Mindstorms.
Morphbots are self reconfiguring modular robots that reassemble or reconfigure themselves while they work. These robots are cool to watch, and are generally still in research laboratories. See Xerox PARC's Modular Reconfigurable Robots page, for some examples.
Unibots are put together to stay, more or less, as a unitary machine. Glue, welded metal, and soldered wires hold together the motors, sensors, wheels, and chips into a single machine. Most robots fall into this category; a robot is probably a unibot unless otherwise noted.
3.3 Where does your 'bot live? Stationbots, Floorbots, Terrainbots, and the Envirobots of air, sea, and space.
A key design aspect of a robot is the expected environment in which the robot will operate. Just as cars, boats, and airplanes are designed differently, so are robots destined for level floors, rough terrain, or underwater use. In special environments, the rigors of operating in the environment affects every aspect of the robots design and operation. Robots have been made for all sorts of special environments from high radiation corrosive environments to the insides of sewer pipes. However, most robots operate in three surface environments.
Stationbots live in one place. They stay at their station, and don't wander by themselves. Stationbots generally have a solid base with some moving parts on top. For example, industrial arm robots can reach out and work with manufactured goods, but require some sort of conveyor to bring the work to them. Other stationbots include computer controlled fine tools such as robotic lathes and CNC mills. You can see a variety of industrial stationbots at .
Floorbots wander around level floors and down hallways. They have wheels or legs or treads to wander around linoleum or carpet and often have sensors appropriate for navigating walls and simple obstacles. Floorbots aren't built to handle the rigors of outdoor life; they are built for flat surfaces with the occasional stair. For example, Honda's humanoid robot at can walk down stairs, but not over rough terrain.
Terrainbots wander over rough terrain. They are designed for outdoor use and can navigate boulders, gorges, and unstable ground. They usually can handle inclement weather, foliage, and rocks. The Nomad in the Antarctic is an example of a big, autonomous terrainbot; see
Envirobots is the general term for robots designed to operating in specialized or hostile environments: The three most common special environments are air, water, and space. Airbots fly in the air. They resemble airplanes, helicopters, and flying balloons. For example, robotic observation planes are currently workbots, see . Seabots swim in the water. Seabots include the traditional, such as Rob Haz's tinkerbot seabot at , and artificial fish such as Aquaroid's zoo at . Spacebots are built for use in outer space, where high reliability, temperature fluctuations, and radiation are issues. There are also hundreds of niche environments, each with their own envirobots.
Robots built for extreme environments can be simply described as an envirobot, or special environment robot. You can also specifically name the environment planned for the robot, e.g., the Sojourner, , is a Mars envirobot.
3.6 How independent is your 'bot: Autobot, Taskbot, RCbot, and Telebot Controls
Robots are designed to function with different levels of independence. Independence is the degree to which a robot relies on control from a human or remote computer. Independence ranges from autonomous robots that function without any human guidance to remote controlled robots where every action of the robot is controlled by a human or remote computer. Independence is not a measure of the complexity of the robot's actions.
Autobots, or fully autonomous robots, are robots that are let loose to run without any further control by a human or remote computer. There is a wide range of complexity in autobots, from robots attempting to mimic humans to phototropic floorbots. Autobots can be turned on and let go; they can function without additional communication. Some autobots will communicate information to another machine, e.g., status and results. Some people like to argue that only autobots are truly robots.
Groupbots are a specific class of autobot; they are a collection of autobots sharing sensor data and working together. See Oakridge National Laboratory's CESAR system at .
Taskbots, or task-oriented robots, perform some steps on their own and pass messages back and forth with a remote computer or human for more directions. Most industrial robots are taskbots, and rely on a remote, central computer to tell them when to run tasks. For example, an assembly line computer might command a welding taskbot to "run welding program 9; trust me that there is an automobile chassis positioned correctly in front of you." The taskbot has some of its own capabilities, but cannot function without direction from outside itself.
RCbots have no onboard decision processing. A remote controller triggers the machinery to move and makes all the decisions for the robot. Radio Controlled (RC) vehicles are RCbots because a human controls them and makes all the decisions via a radio controller, e.g., the robots in BattleBots at .
Telebots, or teleoperated robots, are versions of taskbots or RCbots that try to extend a human operator's perception and capabilities. The operator can see from cameras located on the robot, and many telebots have manipulators on the robot that mimic the operator's hand movements. Telebots are often used in hazardous areas, such as Robominer's mining robots, . They are also used in difficult to reach areas, such as inside the human body. See an article of robotics surgery at . A robot is probably a telebot if it transmits real-time video.
Many robots might fit in multiple categories of independence and may be hard to classify. For example, a manufacturing taskbot might switch modes to become an autobot to shutdown safely during an emergency or when communications are lost. An airbot might fly itself, but could also switched into a telebot mode. To be complicated, if an RCbot were controlled by a remote computer that made all decisions then the RCbot and the remote computer together would be considered an autobot.
3.4 How big is your 'bot: Microbot, Macrobot, and Megabot Sizes
Robots come in every size from smaller than eye can see to large enough to crush your minivan. The way a robot is designed and constructed changes significantly if it is smaller than your fingernail, portable by one person, or huge. Joining two pieces on a microscopic robot uses different tools than joining two pieces on a huge mining robot. Three distinctions for size are sufficient to scope a discussion.
Microbots, or miniature robots, are shorter than a two inches in any direction . This term includes Sandia's miniature bots, , as well as Sweden's microscopic robots, . Microbots are still new, and most are still thoughtbots.
Megabots are larger than can easily be handled by one person. They are heavier than 65 pounds (about 50 kilograms) or longer than two feet (about 0.6 meters) in any direction. Megabots typically need several people and some sort of vehicle to carry them from place to place. Alternately, they are the vehicle. They range from large hobbyist robots to huge monstrosities like the Robosaurus, /.
Macrobots are everything else. A macrobot is a robot that is between two inches and two feet in it's longest dimension, with its arms folded. Macrobots can usually be worked on by one person with hand tools. You can carry a macrobot. When the size of robot isn't mentioned to be a Microbot or a megabot, it's probably a macrobot.
3.5 How real is your 'bot: Thoughtbot, Fantasybot, Simbot, Tinkerbot, and Workbot Development Phases
The science of robotics is constantly evolving. Being clear about what can built, what has been build, and what just looks pretty helps your conversations convey useful information. It also allows you to quickly decide if a conversation is interesting to you; long discussions about robots in film are often uninteresting to people working on robotic simulations and vice versa. Robots exist as thought or fantasy, in simulations, as experiments and works in progress, or as finished products performing some job.
Thoughtbots are robots that have not been built yet or cannot yet be built. These are robots people thought about, wrote papers about, or designed, but have not started building. Many long conversations of thoughtbots concern philosophy and predictions on the effect of future robots on society and humankind. Other conversations read like a planning session of synthesizing several avenues of research into a new robot. It's polite to mention that your new creation is a thoughtbot if you haven't built it yet; our grip on reality is shaky at best.
A fantastybot is a robot that exists only in films, games, art, toys, or other fiction. Fantasybots are a type of thoughtbot that is never planned to be implemented, they exist solely as art. Many people follow the fantasybots or movies and anime as an enjoyable hobby. See for examples of many fantasybots mixed in with real robots, and for robots from the Japanese animation series Robotech. My apologies to the angry artists for having called these "filmbots" in a previous FAQ.
Simbots are robots that exist in simulation environments that provide a graphical, simulated view of the robot interacting with its environment. Simulations are useful for testing new programs for later use with physical robot. Simulation environments also allow research on reasoning, complex interaction of multiple robots, testing designs, and creating innovative software. See IBM's RoboCode software at for an example of a simbot software environment. See for a directory of simbot software packages.
Tinkerbots are robots that are experiments, works in progress, and working prototypes. They are usually works in progress, but not all tinkerbots will ever 'finish' or become workbots. Many tinkerbots are built as continually evolving experiments to test new theories and advance science.
A workbot is a robot in its final form that is used to produce a useful goal. Workbots may be mass produced, such as a robotic lawn mower, or one of kind such a meteor retrieval robot. Useful is loose determination; both mowing the lawn and amusing children count.
Note that each of these types of robots inspires the others. Thoughtbots are argued about, simulated, and then someone builds a tinkerbot. A cool tinkerbot becomes the foundation for a company creating workbots. Real robots often end up as art, such as the real robots in the original Star Wars movie. Art sometimes inspires cool tinkerbots, such as those of Survival Research Labs at . Reality is what you make in the workshop.
4 Getting started - Joining the People of Robotics
First, congratulations on entering an amazing quest. Good luck; may it be fascinating, fun, educational, and profitable for you.
The most common question in any newsgroup is "I'm new; how do I get started?". There are different ways of getting started depending on your background and your interests: you may start as an observer, reading about and watching robots; you might start as a hobbyist, building robots for fun; you may want to study and research robots in academia; or you may want to join the robotics industry in hopes of making some money. Wherever you start, robotics is a rich and fascinating field.
4.1 Watching the art: surveying robotics
You many want to start with a survey of robotics to find out what is being done with robotics. You can find out what's real and what's only in the movies. This can be fascinating and give you enough background in case you want to become more involved.
If you want to start with a book, I recommend "Robo sapiens: Evolution of a New Species". This is a coffee table book, but includes plenty of text in addition to some amazing pictures. It came out in early 2000 and surveys people, institutions, and robots. It is a good way to see what's out there and what is in the laboratories. See ( product link shortened).
On the web, check out NASA's Cool Robot of the week site at . This site features a cool new robot each week, and has a history of cool robots since 1996. NASA also provides a page of resources for educators at . Almost everything about robotics is available on the web; for example, has hundreds of links to other sites.
Popular press coverage can also be found on the web. You can read daily news from , but I prefer Google News at , and . For straight entertainment, check out the Robotica and RobotWars television shows, or watch streaming video at .
Finally, if you want to build or play with some robots, you can buy robots from most toy stores and hobby stores. The Robot Store has a particularly large selection of kits and assembled robots at Tell them I sent you and you can receive a zero percent discount!
4.2 A most enjoyable hobby: building your own robots
A wonderful way to enjoy robotics is to build robots. There are many hobbyists, lots of enthusiasm, and can be a great social activity. There are lots of clubs, web sites, and online communities to help you build robots and let you help others build robots. Most people play with different types of hobby robots without specializing on a particular type. Over time, most hobbyists learn a bit about electrical engineering, mechanical engineering, and computer programming.
Most people start with gizbots, specifically the Lego Mindstorms kit. Lego Mindstorms can be made into many types of robots, are used in several types of competitions, and are surprisingly powerful. On the down side, a set of MindStorms will cost about $200, and requires access to a personal computer. You can find too much information by looking through the Lego Mindstorms web ring at .
In contrast to the Lego Mindstorms kit, the BOEbot (Board of Education) BasicStamp is another high end kit that also costs about $200 and also requires a personal computer. It can be rebuilt into different types of robots. While MindStorms emphasizes creativity and programming, the BOEbot teaches more electronics and mechanics. The BOEbot comes with thousands of pages of experiments and teacher guides. You can read about the BOEbot at
Many people also build unibots, either from kits or from scratch. The kits range in complexity from an afternoon's diversion to a long project. If you want to build your own robot, or transform your kit based robot, I heartily recommend the book "Robot Builders Bonanza". It provides an overview of the methods and tricks of finding wheels that work, using batteries with motors, circuitry, programming microcontrollers, and other advice for putting all the parts together. See ( product link shortened).
Finally, a more difficult, but cheap, introduction is BEAM robots, which are small, autonomous unibots. These have the advantage of being inexpensive, usually under $20, and do not require computer programming skills. They usually require some soldering and patience. These robots are a fascinating attempt at using biology, electronics, aesthetics, and mechanics as design goals. Both they and the related subsumptive architecture approach are the subject of a lot of research. See for more information.
You will probably find it fun and helpful to meet people from a local robotics club. There is a list of some robotics clubs at /. Online, you can be part of an online community such as comp.robotics.misc or Yahoo's . Finally, you can join a league or team, see the section on competition for more information.
4.3 Studying for a living: universities and research
Robots are cool, and, well, you have to go to college anyway. People commonly ask about finding the best university to study robotics at the undergraduate, graduate, and post-doc levels. The simple answer is "it depends," and you will need to do some research to find a good match.
First, recognize that the study of robotics is at the confluence of many different fields, each progressing rapidly. Robotics is a new field, and educators are still learning what to emphasize to efficiently create people skilled in researching and building robots. Every department will be different, and will focus on the large or small, practical or ambitious, with a hardware focus or software focus. Many universities will have robotics groups within their Mechanical Engineering, Electrical Engineering or Computer Science departments. Most universities will have some graduate students studying robotics in fields ranging from Environmental Engineering to Behavioral Psychology.
The universities are all different, and you can learn a lot from the web pages for each college at each university. Robotics is coming to age in a world with the Internet. If you can't get a sense of the focus and direction of the research groups from the web pages, then there is no focus or direction. If the web pages have no gallery of pictures or movies of previous robots then the department probably hasn't built any. Count how many students, professors, projects, and facilities are mentioned to get an idea of the community. Try to get a sense of how they teach about robots; figure out if there are formal classes and at what level. When counting up how many faculty, students, and facilities are involved, check multiple colleges at the university. Finally, try to see if the graduates work in robotics instead of programming computers for a living.
If you are already at a university and are looking for access to more resources, try reading the
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