Mike Burr - log

[comp] tencircuity

Tensegrity is awesome, and recently re-discovered by Reddit.

If you make some temporary (but don't forget `em) simplifying assumptions, you could model a Tensegrity Thing pretty directly as a kind of circuit.

Counter factual assumptions:

  • There are two kind of elements: things that compress and things that tension.
  • The elements have no sense of up/down top/bottom. They're end-to-end symmetrical if you like.
  • The elements are called:
    • compressor, C (the "rods" that can be compressed)
    • tensioner, T (the other one; a cable)
  • The C's and T's are all the same "length". [Let's do away with this one first, as delving into the geometry is a lot more fun with rods and cables of varying length.]
  • These elements may be "attached" at their ends in arbitrary ways. C + T (commutative because of their symmetry), C + C, T + T (interesting). They also may have any number of these combined, that is, the "attachments" may be branching.
  • C has zero tension ability, and T has zero compressor ability. Further, the "physical limits" in this case are ignored. We assume infinite tension and compression abilities. This way we don't have to sum any numbers in our model! It's all just negative or positive (or... 0 and 1 if you prefer)
  • The attachment points are a kind of theoretical perfect gimbal, there is no resistance, all angles are legal (even if C and T take "occupy" the same "space". We can... print a warning if that happens).

I'm pretty sure you could design a "physical" circuit that correctly simulates (modulo above assumptions) and prints a result: "BZZZT, this here C is under tension! Illegal Tensegrity Thing!"

There's endless postulates and proofs regarding triangles that should be directly applicable. Napoleon even did one.

If we want to do away with the "infinite strength" and "unit length" limitations, I'm pretty sure we want an analog circuit. Otherwise, we'd step into modeling analog with digital.

Or or. If we require that we have a discrete number system when tallying tension and compression, the units could be thought of as bits being tracked somewhere in the circuit; "Memory". So when this word fills up it the structure "breaks"... which can happen automatically if we consider an value overflow to automatically mean "exceeded strength".

But it's also true that the analog model could use wire that melt when their corresponding limits are reached? That'd be dramatic.

And for that matter, if analog, what is "compression"? Is this just a matter of stringing together batteries and loads?

In either case, you should get your answer right after you turn the power on.

"Analog?!" you say, "But that'd be like making a Fast and Furious sequel in black and white!"

- 1 toast