The Spider – A Bio Inspired Hopping Toy

For our first project in Design Nature, we were tasked with designing and building a hopping toy. After doing some field sketching of insects, here were the initial sketches of the idea that I ended up going with. Image

One issue with this design was that instead of pushing straight down, the feet of the hooper rotated around a pivot. This was not efficient, since not all of the energy stored in the hopper would be converted into vertical kinetic energy. The solution to this issue was to include a double bar mechanism in what one much consider the thigh of the hopper. You can see this in my first sketch model of the hopper. Image

Constructed using foam core and hot glue, this eight legged sketch model served as a physical exploration of what I was about to CAD. Image

Now down to six legs, the CAD of the hopper was ready to be laser cut and constructed. The parts were laser cut out of a sheet of delrin (polyoxymethylene), and the rest was done by me with the drill press, heat stake machine, and arbor press.

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This is the first prototype, minus the latex tubing springs.

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Here’s a mid project update video recapping what my accomplishments and goals were at the time.

After some testing, it became apparent that the power to weight ratio of the hopper could be improved. I redesigned the next prototype with only three legs.

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The mechanism was quite inefficient due to friction, so although the springs contained enough energy to propel the hopper over 3 meters into the air, it failed to reach 1 m. Ironically, one of the best performing hoppers of my class used a plunger mechanism, essentially doing away with the legs, and designing most of the mass to be contained in the plate that slides up in the middle.

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