Building a brushless powered axe is a bit tricky, as is anything brushless at these scales.
This post is an update on how we're attempting to build the most insane axe robot ever, and we'll go over our progress from our slow axe at Maker Faire to our current axe, which is pretty scary. Hit the jump for videos and math!
We're going to talk a bit about practice, testing, and fun. Isn't fun the whole point of this hobby?
In the last post we talked about brushless vs brushed, modern vs old, etc. I'm going to cut right to the chase:
Castle 2028 Motors and Mamba XLX ESCs are the future of this sport for anything over 30 lbs. Heck, maybe even for a crazy 30. Go buy them:
Castle 2028 Motor
Castle Mamba XLX
This motor and controller combo can handle 7500 watt peak output for a few seconds. Pretty crazy. Ok, so let's backtrack a bit and get back to why these specifically are awesome. Originally I had intended to build a test platform and grab some numbers. Things like a torque/amperage graph, stall torque, that sort of stuff. Then a fun thing happened, my test platform lit on fire.
It wasn't the fault of anything other than some faulty capacitors. It happens. But that was kind of boring. I end up with a fire and I didn't even have a robot yet! Then I found an equation online I probably should have known about to begin with.
Kt * Kv = 1352
(torque is oz-in/a)
This is super useful! Because I know the Kv, this lets me figure out the torque of the Castle 2028 at whatever amperage I want. Super useful for figuring things out like "can this motor push my heavyweight?". This coincided with me finding out about a HW Sportsman Class competition in Florida (Battles at Maker Faire), about a month out.
Could I build a robot in a month? Sounds difficult... but also fun. And isn't that the whole point of a hobby, to have fun? Read on for a high-level post about how we built and fought Mega Melvin in a month: