Slashdot Mirror
Ankle Exoskeleton Takes a Load Off Calf Muscles To Boost Walking Efficiency
Zothecula writes We might have started off in the water, but humans have evolved to be extremely efficient walkers, with a walk in the park being, well, a walk in the park. Human locomotion is so efficient that many wondered whether it was possible to reduce the energy cost of walking without the use of an external energy source. Now researchers at Carnegie Mellon and North Carolina State have provided an answer in the affirmative with the development of an unpowered ankle exoskeleton."
Indeed, I thought modern humans evolved in Olduvai Gorge
The Omo River site in Ethiopia is the current frontrunner, I believe.
https://en.wikipedia.org/wiki/...
rage, rage against the dying of the light
Don't be obtuse. It's clear that what they're getting at is that it isn't externally powered when they say it's "unpowered".
Moreover, you've failed to consider how different efficiencies can affect the situation (i.e. the real world is not a frictionless vacuum). Yes, moving more mass means requiring more energy...output energy. But what we're concerned with here are inputs, since that's what we're expending.
Just to drive home the importance of the distinction between inputs and outputs (and also to toss in an obligatory car analogy), consider the Tesla Model S. It weighs about 50% more than a Toyota Camry, which means it'll take a greater energy output to move than the Camry. That said, the Camry's engine is only about 1/3 the efficiency of the Tesla's, which means that despite its lighter weight you'll still have to put more energy into it than the Tesla to get it to move the same distance.
The same applies here. Yes, adding an extra mechanism adds more weight, which means that the necessary energy output is greater. That said, your calf is inefficient at locking up during the downward part of your step, whereas a mechanical clutch is quite efficient at locking up, so by relying on simple machines to divert those forces to the clutch instead of your calf, you can reduce your dependency on an inefficient system (i.e. your calf), thus reducing the amount of input energy necessary, to the tune of 7%.
Or, hey, it's impossible. Because efficiency isn't a thing. How do you breathe in a frictionless vacuum, anyway? :P