Thread: Team Update #18
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Unread 18-03-2011, 10:04
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Ether Ether is offline
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Re: Team Update #18

Quote:
Originally Posted by boomergeek View Post
I believe Ether's number are based on actual lab trials.
I.e., the specification provided by Tetrix was no where near sufficient to extrapolate to a 10.8 ft/sec estimate. It was only a team member that went in a lab with dynamometer capability and did lab trials with and without the gearbox attached that allowed for the calculation.
Thank Richard for the creating the data AND sharing the data that allows physics teachers to let this rise above tinkering status.
http://www.chiefdelphi.com/forums/sh...+dynamomet er
He (along with many others) already thanked Richard in post#5 of the thread you linked. But thanks once again, Richard :-)

Be aware that the calculation does not include any consideration of the time it takes the bot to accelerate to the indicated top speed. So if you use the top speed to calculate how long it will take to get to the top of the pole, the answer will be optimistic.

I'm going to take a look at a calculation that includes acceleration. I'll have to eyeball data from Richard's power vs torque curve (I didn't see raw data posted anywhere - is it available?). From other Tetrix curves I have seen, the motors are a lot less linear than other motors we've worked with, so I'll least-squares-fit a polynomial. Since the torque depends nonlinearly on speed, and the speed is the integral of acceleration which in turns depends on torque it's an interesting differential equation.



Last edited by Ether : 18-03-2011 at 10:06.
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