Quote:
Originally Posted by AdamHeard
If there is something to be learned here it is that any motor in the kit (even the globe) can be used to power the arm.
I like the philosophy of 330 on arms though; keep them simple, and then gear them down A LOT so that they have so much torque you never have to worry about it. A mentor of theirs, Chris Husmann, gave a great presentation last fall on arms that I would love to get a copy of.
When we had to redo our arm after a regional this year, we took that advice and used a small CIM paired with an AM planetary for each joint (the "team 60" arm).
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I can't emphasize this enough. Over design the power transmission on the arm. If calculations show that you need 30 ft-lbs of torque to lift the arm and object at the end of the arm, then design a motor/transmission combination that can supply that while drawing < 10 Amps! (somewhat dependant on the motor choice)
If you need 30 ft-lbs, then stall torque should be at least 120-150!! Also this way, you can throw in some feedback and PID will have lots of headroom for tuning and working correctly.
In the 7 years of doing FIRST ... In my opinion the ratio of "under-designed arms" to "over-designed (or simply well-designed) arms" is at least 25 to 1.