Re: How much weight are you really carrying?


In article <61p05pF202du8U1@xxxxxxxxxxxxxxxxxx>,
Peter Clinch <p.j.clinch@xxxxxxxxxxxx> writes:
|>
|> Quite! But that very point requires stopping and starting over and
|> again with various bits of your body, which I suspect drags down
|> the efficiency. Certainly gravity will do some of the work, but
|> not by any means all of it. It's difficult to appreciate the
|> complexity of walking as it seems so easy... but it's sufficiently
|> complicated to take a lot of practice before you can do it.

Yes. To take a trivial example, the knee is just a hinge, right?
Wrong. If that were so, knee replacements would be a solved problem,
but they aren't.

From the point of view of energy, the need to use compensatory forces
to hold the limbs semi-rigid is one of the reasons that low and high
cadences are less efficient. The complexity of the compensatory /
balance / rigidity mechanism is one of the reasons that it has taken
so long to develop even the crudest walking robots.

And, if I recall, the few such that they have actually got to work
have used insects as a model and not mammals - let alone the mammal
with extremely aberrant bipedal locomotion, Homo sapiens!

|> That you've got a biomechanical system with such a limited window
|> of use suggests to me it's more complicated than it looks. Which
|> in turn means all sorts of energy wasting opportunities more than
|> it looks...
|>
|> But I'm not smart enough to pin them down, or do more than just
|> worry simple assumptions might not cut it.

Me neither. However, I have done enough reading to realise that it
is even more complicated than I thought at first.


Regards,
Nick Maclaren.
.

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