About Mike the pneuMaggot.
Making the body sections was pretty straight forward. Each body section is more or less the same construction, and link together in the same way.
To plan how the body would move, I installed 1 switch on each body section to either expand or contract 2 pistons. After some headscratching, I found that to make the body travel, only 4 body positions were needed. I photographed the body in each position and used the images to analyse the switch positions. I also made an 8 frame movie using the pictures. Maggot Movie.
Even though there are 12 pistons, to get the body movement right, only 2 switches are needed to acheive the 4 body positions.
I used 2 more pistons, some linkages, and rubber bands to make the switching automatic. The auto switching unit was installed in the 'head' which made it too heavy... so the 'head' has it's own wheels and is simply linked to the body.
Originally I used locked wheels as feet, Mike went sometimes forward and sometimes backwards... so i tried free spinning wheels, again with the same result. I then made up a ratchet to allow the wheels to turn forwards only, now mike takes 3 steps forward and stays on the spot for 1 step.
I rebuit the air compressor, doubling output and increasing storage capacity (see; Air Compressor.) With the new compressor, Mike travels 1 meter in 2 minutes 20 seconds... the movement is still 3 forward & 1 stationary.
Mike the pneuMaggot more or less works how I was planning, but he's just too slow. The main reason is the weight that is lifted on each step to created forward movement. I am going to make a faster pneumatic caterpillar, keeping all parts on the ground and using a in/out movement... keep an eye out for Colin!
Piccies of Mike
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