In order to bear the weight of my body and the entire rat costume without getting exhausted and TOTALLY sore, I’m building a partial exoskeleton that will relieve some of the load, even if it does end up limiting my ROM a bit. It’s still really basic. I have to make a wrist joint (I’m thinking torsion springs– from a rat snap trap!), secure things, and make a ball-and-socket-esque joint for the part that goes on my chest.

This mechanism will only bear my weight when I’m in a specific position, with the stock of the modified crutch aligned perfectly over the base, making a pillar. That’s tough to build onto a body that’s going to be moving around and changing orientation in relation gravity. Refining the relationship between the massive tension springs (Ace Hardware, $10) and the aluminum tubing will help the springs lock and prevent buckling. The shafts inside the spring are about 3 inches apart to allow for more flexion, with loose bolts preventing spring slippage along the shaft, but allowing slippage around the rotational axis. That means at the wrong orientation the springs easily buckle. Too many degrees of movement… must find the happy balance.

The spring on the rear side is placed lower on the shaft to allow for spiraling around my arm, similar to how our muscles spiral/wrap around our bones, which are also spirals. The whole dang human body is a collection of spirals. Eventually I want my hand to be completely free, not holding on to the handle of the crutch, so thumbs can operate the pan-tilt camera eyes and the fingers can puppeteer the rat fingers.

I’m imagining something similar to chest armor, but without the faux leather pants and pads, though I like the rigid plastic spine– good for mods. Right now the center of gravity falls into the crook of my arm, but if I modify that part into an L shape going towards my center, with a joint that allows weight bearing and a quarter sphere’s worth of ROM, and increase the surface area that interfaces with my chest, I can spread the load from one point to possibly my entire upper torso.

Below is the demo-video with a free stand. Imagine both arms having this mechanism.

Tags: Animals People and those Inbetween, arturo vidich, Mechanisms and Things That Move, RATS

This entry was posted on Saturday, April 3rd, 2010 at 1:02 am and is filed under Animals People and those Inbetween, ITP, Mechanisms and Things That Move. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.