Shape Memory Alloy Whole Skin Locomotion

Winner: Soft Robotics Toolkit Design Competition 2018 - College Division.

 

When I was younger I used to play with a toy called a water wigglie. These toys fascinated me because no matter how hard I held onto them, they always managed to slip out of my hand. The toroidal geometry of the wigglie allows it to accomplish this feat because the toy is still able to invert, even if all exterior sides are fixed. A robot in this geometry would excel at navigating tight spaces such as collapsed buildings and the human gastrointestinal tract. During my sophomore year at Olin, I led a group of students in independent research developing a shape memory alloy driven toroidal drive system. Our system works by using NiTi contractile rings to squeeze the back end of an elongated fluid filled torus to promote toroidal inversion and forward locomotion. Our system is capable of moving at speeds up to 3mm/s. I led the design, testing, evaluation, and documentation of the drive system.

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Why A Torus?

When most people think of locomotion they think of wheels. However, wheels have a drawback where only half of the surface contributes to forward motion and the other half opposes it. This can make rolling through small spaces difficult. Toroidal inversion does not have this problem because the entire exterior of the torus moves in the same direction returning though the center.