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Definitions of Terms
Attenuate - To reduce or shorten the process (pulse) length.Excitatory - To produce increased activity or response in a neural network; stimulate.
hFE - DC current gain.
Inhibitory - To suppress activity or response in a neural network; supress.
Nervous Net - a hardware based system of electronics that doesn't rely on programmed code to converge on successful and adaptable walking gaits for robots. It is characterized as a robot "Spinal cord" that takes care of the low-level (but complex) task of walking, versus the more mainstream "Neural Net" which apparently is more comparable to what a brain does. A nervous network is composed of any self-reseting differentiator with an avalanche gain greater than its decay value--connected in patterns laid out in paper Living Machines by Tilden and Hasslacher. Mark Tilden's patent US#5,325,031 is available online (where is detailed in the FAQ, BEAM robotics FAQ: What is a Nervous Network?), and describes the behavior and basic circuitry. Also see the AM Innovations website by Andrew Miller for more information on constructing a nervous network.
Negative Logic - refers to a lower voltage being used as a "1" and a higher voltage level being used as a "0", as opposed to regular logic, which is opposite.
Nv - abbreviation for Nervous net. Which seems to be interchangeable with the older acronym coined by Mark Tilden "VSPANS" (Very Slow Propagation Artificial Neural System).
Nu - abbreviation for Neural net. Similar to a Nv net, but a practical difference is that Nv and Nu neurons are laid out a bit different-basically swap the resistor and the capacitor so you have resitors runing between output and input and caps tied to ground.
Neuron - a single control point in the Nv that is responsible for a single action on the robot.
Nv Process - The pulse that travels thru the Nv net which activates each neuron it passes.
PNC - The pulse neutralization circuit is driven by an integrative neuron that has a relatively long (at least in comparison to the microcore loop) time delay. When the power first hits the circuit, the output of this neuron (which isn't your usual, everyday, microcore differentiating neuron) is immediately and reliably such that the pulse neutralization circuit is in process-eating mode. Thus, even though the microcore has powered up saturated, the pulses fail to get past the neutralization circuit. Finally, the integrative neuron saturates and its output drops. The last process to enter the neutralization circuit is then released, thus permitting one and only one process in the microcore.
Solar Engine TypesThere are three types of solar engines:
- Type-1 Solar Engine- voltage controlled trigger, such as this solar engine
- Type-2 Solar Engine- time controlled trigger, an example would be a Happy Birthday Singer chip or a NvNet walker utilizing an oscillator to cycle between states of charging and walking.
- Type-3 Solar Engine - Charge curve differentiated (i.e., when the charge rate of the capacitors slow down, it triggers) - the most efficient, but never seen one.
The original Type-2 (time) was based around the "Happy Birthday Singer" (HBS) chip that was pulled from greeting cards. These particular models that were modifiable are no longer available. A 555-based timer circuit draws over 10X the power (3-6uA for the HBS, 30-65uA for the 555). See Radio Shack's "Forrest Mimms" book on the 555 (the whole series is excellent).
As for the Type-3, this was a theoretical solarengine. It is based on the idea that the solar engine (SE) should trigger as soon as the charge-curve slope falls below a certain slope (thusly the "differentiating" is required). That is, when the power capacitor starts to "top off" because the solarcell has nearly done all the charging it can, the circuit would fire. In bright light that may mean near 3.5V, or 1.2V in dim light. In any case, it would be the optimum in triggering. The circuit would simply monitor when the power coming from the solarcell starts to taper off, then trigger the SE. To design this, you would know how to use a high-efficiency op-amp and an oscilloscope to tune, and it is not know if the power draw of the circuit would offset the increase in efficiency.
other definitions to be later incorporated into this page.
Copyleft 1996-1998, Brian O. Bush
Brian O. Bush / bushbo@mediaone.net
Updated: Apr. 19th, 1998