Quote:
Originally Posted by RichardNixon
we are using vexpro single reduction gearboxes and there is a noticeable difference between the wheels when spun by hand.
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The difference when spun by hand is the first place to look. There is apparently unequal drag (friction) among the wheels, which would definitely cause the unequal output speeds, especially at low speeds where the drag is a larger fraction of the total output of the motors. Check for misalignment in the various shafts, bearings, and gears. If you are unable to completely remove these differences and don't have enough time, energy, or expertise for encoders, you will probably want to find settings for each wheel which produces the same output speed when on blocks and driving slowly. Then add the differences in those amplitudes to the ones which require extra voltage. For example, if the four wheels require 10%, 8%, 7%, and 6% to make the same low speed, always add 4% to the amplitude of the first, 2% to the second, and 1% to the third. When driving the wheels backward, you will actually need to subtract these percentages to increase the amplitudes.