Quote:
Originally Posted by Ether
Imagine you have 2 robots which are identical in every way, except that Robot A is geared for 8 fps, and Robot B is geared for 16fps but has the motor voltage limited to 50%.
Which robot has better fine control of small slow-speed motions?
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Since robot A is geared lower, it will have finer control on slow speed motions for two reasons.
First, since you are utilizing a pulse width for your transmission of the speed signal, and these microcontrollers only have so much fidelity in their creation of an arbitrary length pulse, being able to utilize 0 o 100% power in robot A instead only half of your available discrete 'steps' of width will give you better control of the motor speed.
Second (and most importantly), in order to start moving from a stand still, there are static frictions that must be overcome in the gearbox and in the wheel-carpet system (if your are turning). These static frictional will be overcome and turn into kinetic ones once a certain torque is applied, and since that torque happens at a 50% lower motor voltage level on robot A than it does on robot B, robot A will have much finer control. In a high speed drive, if you go to make a small adjustment, odds are you have to apply a high enough motor voltage that once you do begin to move, you have already overshot your target. Once the static forces are overcome, it is possible to slow down slightly depending on the difference in the coefficients form static to kinetic, but once again robot A will be able to withstand motion at a lower speed, which I believe would be roughly 50% lower than robot B.
Those are my thoughts, and as for the balance of speed vs torque, for those reasons I think it is still important to balance torque and speed this year correctly. Just because there is no defense doesn't mean it is a good decision to gear your robot as fast as possible.