ROBOTS  What are robots and how do they differ from other machines?  David and Eileen examine what makes a robot what it is.
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Getting Started

Robots are often used to work in environments that are either inaccessible or too dangerous for humans. Have students think of some places where robots are used today. Ask them what guidelines they can use to determine if something is truly a robot. Then have them watch the video segment and play "Bot or Not?"!


When people hear the word "robot," the first thing that usually comes to mind are the shiny metal androids featured in classic science fiction movies. While machines resembling C­3PO and R2­D2 have been built, they are more the exception than the rule in today's robot community. More often than not, modern robots look nothing like humans. Their forms are usually the result of the functions they have been created to perform.

By definition, a robot is an electronically controlled device programmed to conduct a series of tasks that would normally be carried out by humans. Like computers, robots follow only those commands that have been placed in their microprocessor brains. Without proper programming, robots would not be able to carry out even the simplest function. While robots are not capable of thought in the traditional sense, their programming often allows them to make decisions through a process known as feedback.

Simply stated, feedback is the process where information is taken in, analyzed, and then used to make an adjustment in a system. All feedback systems, whether living or mechanical, have three main components. Sensors, which can be as sophisticated as the human eye or as simple as a photo cell, collect information and send it to a comparer, which analyzes the data by comparing it to some set standard. In living things, the comparer is usually the brain, while in robots, it's a microprocessor.

If the sensory data shows that the system is not working according to the standard, the comparer sends a message to an adjuster that changes the way the system is operating. In a human eye, the adjuster may be the iris, which controls how much light strikes the eye sensor, the retina. In the case of a robot, the adjuster might be a set of gears, hydraulic valves, or pulleys that control how much pressure is exerted or in which direction the robot moves.

As computers get more powerful and programs get more sophisticated, simple feedback systems in robots are being replaced by artificial intelligence. As the name suggests, artificial intelligence (AI) is an attempt at mimicking true thought processes used by humans and other sophisticated creatures. While full­fledged reasoning is still many miles down the technological highway, new advances in AI have given robots the ability to learn from their mistakes, recognize patterns, make simple decisions, and even comprehend spoken words. With continued advances in AI, it´s only a matter of time before we all have our own robots to take care of the housework, walk the dog, and do the shopping!

How is the feedback system in a human eye comparable to the one found in an auto-focus camera? How might this technique be used in a robotic space probe designed to take pictures of a distant planet?

Student Activity
Discover the limitations of mechanical sensors used by robots.


How difficult is it for mechanical sensors to collect information in robotic systems? Because the human sense of touch is so well developed, it´s hard to imagine what type of information a mechanical hand might obtain. See how "sense­ible" you can be when you try to gather information about the size and shape of an object using nothing but a mechanical sensor.


  • large, open cardboard box approximately 40 by 30 by 20 cm (16" by 12" by 8") (The kind that copier paper comes in works great.)
  • wooden dowel approximately 30 cm long
  • piece of opaque fabric large enough to cover the box opening
  • masking tape
  • 1. Discuss how the sense of touch allows you to determine the size and shape of an object, and then imagine what it would be like if the only way you could "feel" something would be through the use of a mechanical probe.

    2. Set up the sensory box by using the masking tape to drape the fabric over the opening of the box. Turn the box on its side and set it up in the middle of the table. Each person in the group should select one mystery object for placement in the box, making sure the other members of the group do not see it.

    3. Place the first object in the box and have each member of the group try to collect as much information as possible on the size and shape of the object by slipping the wooden dowel under the drape and using it to "probe" the object. After all team members have collected their data using the stick, they should draw a picture of what they think the object looks like. Repeat the procedure with the other mystery objects. After all the individuals have finished, compare the drawings to the actual objects.

    Extend the activity:

    How does your sense of touch improve when you use your own hand? Once you have completed the activity using the wooden sensory probe, try repeating it with a different set of objects­only this time, use your hand to collect the data. How might you design a probe or set of probes that more closely resembles the human hand? For example, how would applying wax or soft clay to the end of the dowel affect how the object feels?


    1. How did using a probe limit the amount of information you could gather?

    2. How might changing the diameter of the dowel help change the "resolution" of the data collected?

    3. Would changing the material that the probe is made from help you collect more useful data?


    Brian Show Number: 1501


    Books and articles

    Brooks, R. (1991, Sept)
    New approaches to robotics.
    Science, pp. 1227-1232.

    Rosheim, M. (1994)
    Robot evolution: The development of anthropomorphics.
    New York: John Wiley & Sons.

    Suplee, C. (1997, July)
    Robot revolution.
    National Geographic, pp. 76-95.

    Computer Software

    Isaac Asimov's The Ultimate Robot.
    Available in catalogs.


    Robotics Society of America
    P.O. Box 1205
    Danville, CA 94526-1205
    (415) 550-0588

    Web sites

    Mobile Robot Laboratory Research Projects

    The Robot Group

    Robotics Internet Resource Page

    Learning Curve Toys
    (Robotix Construction System)
    fact sheet

    Try This:

    Even the simplest task must be programmed into the robot's memory in a sequence that the machine can follow. Write a simple flow chart/program that commands someone else to perform a specific function­shoot a basketball, move a desk, etc. Account for every action in the proper sequence and leave nothing open-ended. Have someone follow your programming to get the job done.

    Try This:

    While many science fiction movies have been based on robots resembling humans, building a robot that can walk like a person has proven to be an exceptionally difficult task. Research the Pathfinder's rover Sojourner to find out how scientists built it to move across the surface of Mars. How might you design a robot?

    Try This:

    Feedback systems in robots closely resemble those that keep our own bodies in balance. To see a simple feedback system at work, get a small flashlight and stare into a mirror. Shine the light into your eye and see what happens. How fast does this reaction occur? What controls it?

    NEWTON'S APPLE video cassettes and educational materials provide further information about this and other topics. Call 1-800-588-NEWTON.

    Copyright 1997,
    Twin Cities Public Television

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