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Unread 13-01-2016, 13:16
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JesseK JesseK is offline
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Re: 9 ft/sec for an 8" wheel drive?

It's difficult to calculate all of that stuff using JVN's sheets alone. JVN's has been irreplaceable in its cross-references of gearboxes this year, but that one piece means it shouldn't be used alone.

Search CD-media for 'calculator'. There are tons, each with their merits.
Here is mine, but I haven't updated it in a long time so the motor data is invalid. There are also a couple of nuances:
  • Mecanum selection improperly reduces applied torque for acceleration
  • "Time To Goal" is the old nomenclature for the modern "Sprint Distance"
  • It doesn't account for battery voltage, so there is error of about 3% in the time and current draw calculations - small, but still not exacting. Accounting for battery voltage and then solving for 't' is actually very difficult.
  • "Actual" Speed varies a bit because it measures time from t=0 to the amount of time it takes to get to the goal, rather than calculating a maximum speed. So a new version of this sheet would include that as well.

Attached is a notional output for one specific scenario (but not necessarily what we will end up with).
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Last edited by JesseK : 13-01-2016 at 13:19. Reason: attachment
 


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