Elastic Members

"But everybody knows that any closed loop motion by any mechanism free of internal and external frictions is energyless."

And everybody knows there ain't no free ride. Where will you come up with this perpetual motion machine that is free of friction?

when the temperature of certain ceramics are lowered to near absolute zero, they seems to defy the laws of physics. they are capable of levatating and spinning without friction.

Sorry, they may be "frictionless", but they won't spin forever. As least not on the surface of the earth.

The mechasism that stores energy requires energy to change it's form from potential to kinetic. Energy cannot exist without something for it to act upon. Energy comes from the sun, but forces are at work to create that energy. That energy is being utilized to create plant and anilmal life on earth. What you may think is energy at rest doesn't happen. Energy is always being used even as we sleep or the charge within a storage battery. Things either grow or die. Either way, energy is present. Growing uses energy; dying creates energy.. I don't know if this makes any sense as it pertains to your thread.

being able to store potention energy then release it at a given time is rare in the animal kindom, but many marsupials are able to do it. i've read that the military has come up with mechanical devises for solders that are capable of doing just that. it is basically an extoskeleton that attaches to a solders legs that allows him to carry heavier loads over longer distances.

Natural Evolution is a complex set of chained events that fInally produce amazing end results.

How true.

Beetles beat us to the screw and nut

Various insects/dinosaurs/birds also beat the Wright brothers. To some extent, maple and other samaras also beat the helicopter.

that reminds me of a flea that can jump amazing heights compared to it's boby size.

But everybody knows that any closed loop motion by any mechanism free of internal and external frictions is energyless.

Agreed but in previous paragraph you have also mentioned that this is with help of a set of muscles.

As one is aware that this is imparted by the contraction and stretch of these (and that loses energy - strain energy and also these muscles are not stretching/contracting in a pure frictionless media.

_{(Not even remotely biologist so may be wrong in assumption)}

There are errors in your assertions

Why then Nature loses ALL the energy of both sets of muscles?.

I don't believe that's true. I think there is some energy recovery in a jogging gait, after all the trailing leg will start to swing back under the force of gravity, also muscles/tendons/ligament are to a great extent elastic and will store/release energy.
I think the human leg system is well tuned to some gaits that's why they are preffered for long distance and that's why we can out run just about anything over long distance/duration.
Del

I don't know how easy it would be to find it, but there was a show on NPR (U.S. National Public Radio) by Scott Carrier, who with friends tried to run down some pronghorns (antelopes, but different from the African ones). As I recall, they didn't quite succeed, but came pretty close. Now just read Masai into this equation....

Our advantage in distance running is our reduced solar gain and better cooling system, not our basic efficiency.

J.E. Gordon confirms that kangaroo tendon is particularly good as a spring.

A rig to add springs to help hold our arms up for repetitive jobs has been in the news lately. This seems like a promising area for research. I wonder who will be first to have their shoes or shorts declared illegal for competition.

At walking speeds, our legs do work as pendulums, with relatively low losses. (We can also add a 25% load on our heads at no loss in power on the level, due to improved frequencies in the trunk.) As we speed up, we have to use muscles as Chorete describes, wasting energy like someone shadow-boxing. At high speeds, we bend the knee considerably to raise the mass of the lower leg and allow a quicker pace, even with considerable cost in energy at the knee.

kangaroos have elastic tendons in their legs that allow them to store the energy from each hop then apply it to to the next hop. it's a very efficient means of locomotion.

Here is a rather ridiculous explanation, highly simplified.

I have tested one complete setup that takes care of limb and foot motions. It is very simple.

The anchor point B is moved up and down just at the moment when the rod passes over its dead point, and so no force is needed.

Kangaroos are well known for having energy storing tendons. Why all other animals DO NOT have this , life or death, very important feature?.

Exactly. This contraption would be perfect for military use in exoskeletons.

The ones being researched by many USA Companies DO NOT use this feature, but standard electric and hydraulic motors.

chorete

moved up and down ....... no force is needed.

perhaps you should look at this more holistically....

what is the system really capable of?

Chris

There is not (not possible) frictionless continuous boxgear perhaps as an example of a bigger law (i don't know what science),control needs energy spent as much as control is required.This is true in mechanics but could be easier to see in electronics:A simple amplfier tries follows the "inlet will" and the out signal needs reduce its gain if tries repeat exactly the input shape.Any superelastic mechanism device will keep into oscilations and needs be braking all the time following a prefixed shape or a changing will.-

That was long time ago.

I cannot find my fullsize protos, but instead there is a rusted 1/3 size model that still works.

I have been trying to make a video so you can see how extremely simple is the link for automatic limb motion, but as usual the camera batteries are dead.

About 38 years ago I bought a Texas Instrument solar powered calculator, and I have kept it with me all this time. It is completely destroyed and completely bent by sitting with my heavy rear end on top of it. The keys are nearly erased and whatnot!

BUT STILL WORKS PERFECTLY. I have never had anything so useful. It works with dim room lights. I believe that they are no longer in the Market, The damned use and throwaway Economy!

chorete

have you considered upper body movement? i think you'll find that the trailing foot will drag unless the hips are forward of your center of gravity, so the upper body is constantly moving as we walk. this takes energy, although there is a possibility of recovering energy as your forward foot takes the weight of your body.

after some more thought, i now realize that trying to recovery energy from the foward leg would only shift the needed energy to the trailing leg. i guess we're still not smart enough to defy the laws of physics.