[ExI] former deceased nfl players...

spike spike66 at att.net
Tue Sep 22 01:26:04 UTC 2015

-----Original Message-----
From: extropy-chat [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf
Of david
>>... We see in nature quadruped and a few biped designs in humans and 
> birds, but as I think about it, I am very surprised evolution never 
> came up with any tripedal locomotion examples... spike 

>...Have a look at the Australian kangaroo. At low speeds it uses tripedal
locomotion with the tail acting as a third leg. At high speeds it
transitions to bipedal jumping, and the tail is used for balance and control


Ja, good point.  Perhaps the bipedal dinosaurs did the same or similar.

For robot locomotion that would be a good choice for some applications.
Mammalian muscle uses energy just holding taut.  Hold any light weight at
arm's length or even just empty handed horizontal arm for just a few minutes
and notice how tired you are.  There is no force times distance, so those
muscles have done no work, but they have used a lot of chemical energy.  A
horizontal tail used for balance in a robot wouldn't use energy just holding

For other applications such as office use, a triped might still be best.
There is no mechanical reason why it couldn't have three legs all nearly
identical, jointed a lot like our legs, with the two outboard limbs working
in parallel with the center one pi radians out of phase.

I need to put together a JavaScript graphic of that, or have my son do it.


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