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Turtle Obsessions

March 11, 2010

It’s been an interesting couple of weeks.

Shahar was quoted on the ITP List saying, “I have to go work on my turtle!”

I spent a few hours up at the American Museum of Natural History trying to get a better understanding of turtle skeletons.  These are skeletons of some of their prehistoric ancestors:

The cavernous shell makes room for the tremendous shoulder blades, which develop the muscle leverage necessary to lift their weight off the ground.  See this section again.

Two other examples:

So we began by trying to construct models of the skeletons:

At this juncture, the joints are almost completely unconstrained though.  So the next step was to begin thinking about the linkages necessary to transfer energy through the joints with the appropriate motion.  Here’s a great video of the motion we were seeking to emulate:

Shahar also found an excellent journal article, “A Structural and Functional Analysis of Walking in the Turtle, Chrysemys picta marginata” by Warren F. Walker, Jr., Department of Biology, Ohedin College, Oberlin, Ohio, 1971:

TurtleMotionDiagram

And here was our first pass:

Getting the hips moving:

And the front arms:

A Turtle Drawing Machine:

Putting it together, and getting the legs moving with the hips–okay, one leg:

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From → Mechanisms

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  1. Turtles – bits and pieces

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