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PowerPedia:BEAM

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The word BEAM is an acronym for Biology, Electronics, Aesthetics, and Mechanics. BEAM engineering methods include (and are to a varying degrees applied): [A] Use the lowest number possible of electronic elements ("keep it simple"), [B] recycle and reuse technoscrap. and [C] use radiant energy (such as solar power) This is applicable to all design problems and engineering tasks (wuch as generator construction and power systems).

The term is usually used in a style of robotics that primarily uses simple analog circuits instead of a microprocessor in order to produce an unusually simple design (in comparison to traditional mobile robots) that trades flexibility for robustness and efficiency in performing the task for which it was designed. Exceptions to the convention of using only analog electronics do exist and these are often colloquially referred to as "mutants".

Contents

Mechanisms and principles

The basic BEAM principles focus on a stimulus-response based ability within a machine. The underlying mechanism was invented by Mark W. Tilden where the circuit (or a neural network [referred to as a "Nv net"] of artificial neurons [called Nv neurons]) is used to simulate biological neuron behaviors. Some similar research was previously done by Ed Rietman in 'Experiments In Artificial Neural Networks'. Tilden's circuit is often compared to a shift register, but with several important features making it a useful circuits.

There are a large number of BEAM designs to use solar power from small solar arrays to power a "Solar Engine" which creates devices capable of operating under a wide range of lighting conditions. Besides the simplistic computational layer of Tilden's "Nervous Networks", BEAM has brought a multitude of useful tools to the toolbox. The "Solar Engine" circuit, many H-bridge circuits for small motor control, tactile sensor designs, and meso-scale (palm-sized) device construction techniques have been documented and shared by the BEAM community.

BEAM focus

Being focused on "reaction-based" behaviors (as originally inspired by the work of Rod Brooks), BEAM attempts to copy the characteristics and behaviors of natural organisms, with the ultimate goal of domesticating these "wild". BEAM also promotes the value of aesthetics in the design of the device, proving the adage "form follows function" (a good-looking device is often better built and more robust than a poor-looking one).

Disputes in the name

Various people have varying ideas about what BEAM actually stands for. The most widely accepted meaning is Biology, Electronics, Aesthetics, and Mechanics. However, there are many other semi-popular names in use, including:

  • Biotechnology Ethnology Analogy Morphology
  • Building Evolution Anarchy Modularity

Microcontrollers

Unlike many other types of devices controlled by microcontrollers, BEAM devices are built on the principle of using multiple simple behaviors linked directly to sensor systems with little signal conditioning. This design philosophy is closely echoed in the classic book "Vehicles: Experiments in Synthetic Psychology". Through a series of thought experiments, this book explores the development of complex devices behaviors through simple inhibitory and excitory sensor links to the actuators. Microcontrollers and programming are usually not a part of a traditional (aka., "pure" ) BEAM devices due to the very low-level hardware-centric design philosophy.

There are successful device designs mating the two technologies. These hybrids fulfill a requirement needing robust control systems with the flexibility of dynamic programming, like the "horse-and-rider" topology BEAM (ed., The ScoutWalker 3 is such a device. The physical devices body (the "horse") is controlled by traditional BEAM technology, and the microcontroller and programming influences (and if needed, subsumes) the devices' body from the "rider" position . The rider component is not necessary for the device to function, but without it the device will lose the important influence of a "smarter brain" telling it what to do.

Types

There are various "-trope" BEAM, which attempt to achieve a specific goal. Of the series, the phototropes are the most prevalent, as light-seeking would be the most beneficial behavior for a solar-powered device.

  • Audiotropes react to sound sources.
    • Audiophiles go towards sound sources.
    • Audiophobes go away from sound sources.
  • Phototropes ("light-seekers") react to light sources.
    • Photophiles go toward light sources.
    • Photophobes go away from light sources.
  • Radiotropes react to radio frequency sources.
    • Radiophiles go toward RF sources.
    • Radiophobes go away from RF sources.
  • Thermotropes react to heat sources.
    • Thermophiles go toward heat sources.
    • Thermophobes go away from heat sources.

General

BEAM devices have a variety of movements and positioning mechanisms. These include:

  • Sitters: Unmoving devices that have a physically passive purpose.
    • Beacons: Transmit a signal (usually a navigational blip) for other BEAM devices to use.
    • Pummers: Display a "light show".
    • Ornaments: A catch-all name for sitters that are not beacons or pummers.
  • Squirmers: Stationary devices that perform an interesting action (usually by moving some sort of limbs or appendages).
    • Mag: Utilize magnetic fields for their mode of animation.
    • Flagwavers: Move a display (or "flag") around at a certain frequency.
    • Heads: Pivot and follow some detectable phenonomena, such as a light (These are popular in the BEAM community. They can be stand-alone devices, but are more often incorporated into a larger devices.).
    • Vibrators: Use a small pager motor with an offcenter weight to shake themselves about.
  • Sliders: Devices that move by sliding body parts smoothly along a surface while remaining in contact with it.
    • Snakes: Move using a horizontal wave motion.
    • Earthworms: Move using a longitudinal wave motion.
  • Crawlers: Devices that move using tracks or by rolling the body with some sort of appendage. The body of the device is not dragged on the ground.
    • Turs: Roll their entire bodies using their arm(s) or flagella.
    • Inchworms: Move part of their bodies ahead, while the rest of the chassis is on the ground.
    • Tracked : Use treaded wheels, like a tank.
  • Jumpers: Devices which propel themselves off the ground as a means of locomotion.
    • Vibros: Produce an irregular shaking motion moving themselves around a surface.
    • Spring: Move forward by bouncing in one particular direction.
  • Rollers: Devices that move by rolling all or part of their body.
    • Symets: Driven using a single motor with its shaft touching the ground, and moves in different directions depending on which of several symmetric contact points around the shaft are touching the ground.
    • Solarrollers: Solar-powered cars that use a single motor driving one or more wheels; often designed to complete a fairly short, straight and level course in the shortest amount of time.
    • Poppers: Use two motors with separate solar engines; rely on differential sensors to achieve a goal.
    • Miniballs: Shift their center of mass, causing their spherical bodies to roll.
  • Walkers: Devices that move using legs with differential ground contact.
    • Motor Driven: Use motors to move their legs (typically 3 motors or less).
    • Muscle Wire Driven: Utilize Nitinol (nickel - titanium alloy) wires for their leg actuators.
  • Swimmers: Devices that move on or below the surface of a liquid (typically water).
    • Boats: Operate on the surface of a liquid.
    • Subs: Operate under the surface of a liquid.
  • Fliers: Devices that move through the air for sustained periods.
    • Helicopters: Use a powered rotor to provide both lift and propulsion.
    • Planes: Use fixed or flapping wings to generate lift.
    • Blimps: Use a neutrally-buoyant balloon for lift.
  • Climbers: Devices that moves up or down a vertical surface, usually on a track such as a rope or wire.

Applications

Robotics

At present, autonomous robots have seen limited commercial application, with some exceptions such as the iRobot Roomba robotic vacuum cleaner and a few lawn-mowing robots. The main practical application of BEAM has been in the rapid prototyping of motion systems and hobby/education applications. Mark Tilden has successfully used BEAM for the prototyping of products for Wow-Wee Robotics, as evidenced by the "proto-Robosapien" "BIODroid", B.I.O.Bug, and RoboRaptor. Solarbotics Ltd., Bug'n'Bots, and PagerMotors.com have also brought BEAM-related hobby and educational goods to the marketplace. Aspiring BEAM roboticists often have probems with the lack of direct control over "pure" BEAM control circuits.

There is ongoing work to evaluate Biomorphic techniques that copy natural systems because they seem to have an incredible performance advantage over traditional techniques. There are many examples of how tiny insect brains are capable of far better performance than the most advanced microelectronics. A think-tank of international academics meet annually in Telluride, Colorado to address this issue directly, and until recently, Mark Tilden has been part of this effort (he had to withdraw due to his new commercial commitments with Wow-Wee toys). A barrier to widespread application of BEAM technology is the perceived random nature of the 'nervous network', which requires new techniques to be learned by the builder to successfully diagnose and manipulate the characteristics of the circuitry. Having no long-term memory, BEAM robots generally do not learn from past behavior. However, there has been work in the BEAM community to address this issue. One of the most advanced BEAM robots in this vein is Bruce Robinson's Hider, which has an impressive degree of capability for a microprocessor-less design.

Power generation

A Solar Engine (also called solarengine and SE) is a simple BEAM circuit which receives radiant energy, capacitates and stores the energy, and then utilizes that energy in pulses to power motors or other loads. Solar engines are electric engines powered by solar cells. Solar engines are composed of relaxation oscillators.

Description

Solar engines behave as a power bank. Solar engines charge gradually and then discharged rapidly (to power a load). Incoming energy is stored up until a useable amount is in reserve and then released suddenly, performing (periodic and incremental) work. Solar engines usually have a resistor, a capacitor, and some sort of "threshold" device. The solar engine advantages include:

  • workable in relatively-low light levels
  • minimal solar cell size

Characterisitics of the engine include:

  • economical,
  • efficient, and
  • ruggedized expansions

Solar engine which have been constructed heretofore have not generate large quantities of electricity. Array of cells can be used to attain more power (though as the number of cells increase, the frame [and its associated weight] is increased; frames are usually made as lightweight as possible to increase speed).

Forms

All links in this section are to Solarbotics.net, a free community site.

Voltage controlled trigger

The predominant form of solar engine.

  • Zener-based : A capacitor charges until a 2N3906 transistor (PNP) is signaled by a Zener diode and turns on. Then a 2N3904 transistor (NPN) turns on and the capacitor is discharged through the motor. As the 2N3904 transistor turns on, a 2.2 kiloohm resistor starts to supply base current to the 2N3906 transistor and the circuit is activated. When the capacitor voltage drops below about one volt, the 2N3906 transistor turns off, the 2N3904 transistor turns off, and the motor deactivates and the process is repeated.
  • FLED-based : When a FLED flashes (around two and a half volts), it conducts and makes the 2N3906 transistor (PNP) signal a 2N3904 transistor (NPN) which, in turn, supplies current to a motor. When the NPN transistor triggers, the FLED is essentially out of the circuit. When the voltage drops to around one-half volt, the transistors idles and the process is repeated.
  • 1381-based : As a solar cell charges a capacitor and the voltage rises to the 1381's trigger voltage, the 1381 voltage trigger IC signals a 2N3904 transistor. The 2N3904 transistor signals a 2N3906 Transistor, which, in turn, supplies current to the base of the 2N3904 transistor. The current then activates a motor. When the voltage drops to around one-half volt, the transistors idles and the process is repeated.
  • FRED SE ("Mazibug")
  • The "Miller engine"
  • GBSE ("Gate Boost Solar Engine")
  • "MicroPower"
  • VTSE ("Variable Threshold Solar Engine")
  • DSSSE ("dual slope-sampling SE")
  • "Chloroplast"
  • Vx2SE ("voltage-doubling solar engine")
Time controlled trigger

Less efficient, but activated at specific times.

  • HBS ("Happy Birthday Singer" greeting card) chip
  • 555 chip
Charge curve differentiated

Theoretically most efficient.

  • T3SE "Type 3 SE" by Wilf Rigter
  • Tritium by Ben Hitchcock
Nocturnal

Charges during light exposure and discharge when dark.

Publications

Patents

  • U.S. Patent 613809 (G.patent; PDF) - Method of and Apparatus for Controlling Mechanism of Moving Vehicle or Vehicles - Tesla's "telautomaton" patent; First logic gate.
  • U.S. Patent 5325031 (G.patent; PDF) - Adaptive robotic nervous systems and control circuits therefor - Tilden's patent; A self-stabilizing control circuit utilizing pulse delay circuits for controlling the limbs of a limbed robot, and a robot incorporating such a circuit; artificial "neurons".

Books and papers

  • Conrad, James M., and Jonathan W. Mills, "Stiquito: advanced experiments with a simple and inexpensive robot", The future for nitinol-propelled walking robots, Mark W. Tilden. Los Alamitos, Calif., IEEE Computer Society Press, c1998. LCCN 96029883 ISBN 0-8186-7408-3
  • Tilden, Mark W., and Brosl Hasslacher, "Living Machines". Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
  • Tilden, Mark W. and Brosl Hasslacher, "The Design of "Living" Biomech Machines: How low can one go?"". Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
  • Still, Susanne, and Mark W. Tilden, "Controller for a four legged walking machine". ETH Zuerich, Institute of Neuroinformatics, and Biophysics Division, Los Alamos National Laboratory.
  • Braitenberg, Valentino, "Vehicles: Experiments in Synthetic Psychology", 1984. ISBN 0-262-52112-1
  • Rietman, Ed, "Experiments In Artificial Neural Networks", 1988. ISBN 0-8306-0237-2
  • Tilden, Mark W., and Brosl Hasslacher, "Robotics and Autonomous Machines: The Biology and Technology of Intelligent Autonomous Agents", LANL Paper ID: LA-UR-94-2636, Spring 1995.
  • Dewdney, A.K. "Photovores: Intelligent Robots are Constructed From Castoffs". Scientific American Sept 1992, v267, n3, p42(1)
  • Smit, Michael C., and Mark Tilden, "Beam Robotics". Algorithm, Vol. 2, No. 2, March 1991, Pg 15-19.
  • Hrynkiw, David M., and Tilden, Mark W., "Junkbots, Bugbots, and Bots on Wheels", 2002. ISBN 0-07-222601-3 (Book support website)

Related

People

Robotics

  • Wired intelligence: a robot that has no programmed microprocessor and possesses analog electronics between its sensors and motors that gives it seemingly intelligent actions.
  • Behavior-based robotics: branch of robotics that does not use an internal model of the environment.
  • Emergent behavior: the process of complex pattern formation from simpler rules.

BEAMbot types

  • Photovore: a robot that seeks light and uses it to power itself.
  • Solarroller: a dragster robot run by solar light.

Other

Elements

  • Monocore: This term can specifically mean one Nv neurons which is a simple oscillator. More generally, though, it is used to denote the connection of a pair of bicores.
  • Bicores: Nv network loop-topology with two Nv neurons. There are grounded bicores and suspended bicores.
  • Tricore: Nv network loop-topology with three Nv neurons.
  • Microcores: Closed-loop implementation of a nervous net responsible for direct actuator control. Any Nv network greater than or equal to four, but specifically any multiple numeric prefixed cores (such as a Quadcore, Quincore, Hexcore, Septcore, Octacore, etc.)

External articles and other references

G
Web 		Sites on BEAM
via Google Search
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Image 		Images of BEAM
via Google Image
G
groups 		Newsgroups with BEAM
via Google Groups
G
News 		News of BEAM
via Google News
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Other resources
BEAMbots
  • Robinson, Bruce N., "Hider". Robinson's Robots, 2005.
  • Solarbotics, "The ScoutWalker 3". Competition robot kit.
Interviews and news

See also

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