Quote:
Originally Posted by Paul Copioli
All,
Warren is absolutely correct in that my analysis did not include the dead weight of the trailer. The robot still has to accelerate the trailer, ...
accel = 0.79 * g * Mu
Warren's estimate was pretty darn good at 75%. If your robot mass is less, then your ratio gets smaller and you will have a lower available acceleration.
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Therefore, max weight overpowered robots have most acceleration.
I get max acceleration of about 1.5 fpss, and top speed of 10fps,
which is top wheel speed of about [overstrike]32rpm [/Overstrike] 380rpm
Here are two opposite approaches to gear design to aid traction control:
- use little to no reduction on motors so that the peak motor torque is near the friction x torque on wheel. Highcurrent on slow speed motors.
Note Low rotational momentum of gear train, and high current deltas.
Jaguar speed controllers are reported to be better at low speed control.
I don't like this approach....
- use huge reduction (5000/32?) on motors so that the fuller range of motor speeds can be applied and more torque to drive wheel at exactly right speed.
No reason for wheels to ever go > 380rpm.
Note higher rotational momentum of gear train, but lower current deltas.