Monday, October 21, 2013

Update on flexibot

A few days ago I cast two more flexible links for my flexibot development platform.  My initial link was a #1 SRFLG (standard RobotGrrl flexible link guage) - about 4 mm diameter.  The two new ones I cast are a #2 SRFLG - about 6 mm in diameter, and #3 SRFLG - about 7 mm in diameter.
After they cured, I started flexing them with my fingers, just to get a feel for the flexibility.  My #3 quietly failed.
Close inspection of the crack seems to indicate there was internal structure to the link, so the Sugru isn't homogeneous.  Either I didn't get the Sugru squished together well enough, or didn't let it cure long enough. Oh well.  I've made 4 links, and experienced 50% failure rate.  I guess I have something to learn about casting Sugru.

Now, on to the good part.  I put the first flexibot frame together really quickly, and without much planning.  So, I discovered that hot glue isn't real good at take-apart-and-put-back-together prototyping.  I went back to CAD, and modified the frame design to incorporate interchangeable link base plates.

Here you can see my #1 and #2 links on their plates...
Here's the new frame...
and the frame with a link installed, from the front...
and the back...
I haven't yet figured out how I'm going to attach the control cables (actually I'm using polyester thread originally designed to stitch sails together) and still make them interchangeable.

If you have any ideas, leave me a comment.  Thanks for reading.

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