# 4" mecanum circumference

does anyone know the true circumference of the 4" mecanum wheels? I am wanting to convert degrees to distance, and I don’t have any accurate measurements as I don’t have the physical robot or wheels with me.

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The circumference is different than just a plain circle because when it rolls, the part that touches the ground doesn’t stay at constant distance from the axel. when I treated it as a perfect circle, it was fairly off.

I suppose an experiment would be necessary. Have it drive forward 10 rotations, then measure the distance and divide by 10. The more you do will reduce errors like slop in the gears, etc.

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Yeah, I was wondering if someone has the measurements already because I don’t have physical access to the wheels or robot for a week and thus can’t do the experiment. If no one has the answer I will do this when I can access the robot

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Yeah it does. Your test was off for some other reason

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You could open the cad file available at vexrobotics an measure that.

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If that is the case then the shape wouldn’t be a circle and would not have a circumference.

Circumference is used to describe the distance around something, not just always a circle.

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Oh yeah lol
My school always told me it was just for circles so I guess I forgot

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i believe the word you’re looking for is “perimeter”

Circumference is specifically referring to an ellipse.

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Depends on the definition you use.

Okay just, what do you want? We’ve given you everything you need

I had to do the calculations last year for my autonomous. A 4" omni wheel powered by a normal, green cartridge motor goes approximately 12.57" on one rotation. Closer to 12.56(6 repeating), but momentum brings it up to roughly 12.57". I found that it works very well.

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Well, sorry, I guess in the end you were right, the mecanum wheels were just the same as a circle. Thanks for your patience with me as I do a lot of stupids

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