Quote:
Originally Posted by asid61
So a butterfly/ octocanum drive is where you switch between mecanum and traction wheels, right?
I was wondering what the typical weight and complexity of these systems was. This would be weight per module or, preferably, weight of bellypan + drive base + modules. I have only found one weight listing for an octocanum module, and I think many teams keep the mass under 11lbs.
How long does this take to design? Does this need a particular CNC special part or can it be fabricated with a waterjet/ sheet metal shop?
Any information on these drives would be useful, as I'm looking into different drives for a summer project.
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As BJC said, butterfly is [typically] switching between omni and traction wheels; while octocanum is [typically] switching between mecanum and traction wheels.
The main difference between the two are choosing what wheel is opposite of the traction wheel on the pod. While I have not built one, the drives should be slightly heavier than a conventional drive. Majority of these setups use a single gear reduction to the first wheel and then another reduction via chain or belt to the second wheel. This makes up for the weight "missing" from gearboxes.
There are some good examples out there on how they have been constructed in the past. 148 made this type of setup popular in their 2010 release video and their CAD files can be seen on
FRC designs and you can see another iteration in their
2011 robot. Another great example is 3847's robot from this year. It was documented fairly well in their
build blog. Both of these teams are more than willing to help answer further questions, but these should give you a good starting point. There are plenty of other robots that use these drive types that I didn't mention, these were two I could get my hands on quickly.