Thread: fine control of robot with mecanum wheels
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Unread 17-03-2010, 11:20
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Re: fine control of robot with mecanum wheels
Hi Team 868,

Thanks for your reply. I have a bunch of questions, I hope you don't mind. Any answers you are willing to provide would be much appreciated:

My team is using mecanum wheels, I believe we are using the same setup or something similar.

Are you using 8" AndyMark mecanums? Are the wheels direct-driven, or chain-driven? If chain, what are the sprocket teeth counts? Are you using the KoP AndyMark 12.75:1 toughbox? If not, what is your gear ratio? Are you using Victor or Jag motor controllers?

One thing to keep in mind is that everything has a slight polarity, and a deadband. You can work to figure out where the motors start spinning, and then account for it in code.

Yes, we are aware of this. Nothing we have tried so far is able to achieve fine control at low speeds, given our gear ratio and open-loop control.


Also, another thing my team has found useful is separating the rotation component from the XY joystick to another one - we found it was nearly impossible to spin without moving off axis until we did this.

We have no trouble spinning in-place, with the rotation command on the "twist" axis of a 3-axis joystick.


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