What Dr Joe Wants for Christmas...

[Joe Johnson]

...if it arrives by Kick off, I'll be happy.

Reading this thread about how to control an Omni Driver robot, I read about this paper ($1.50 for a copy from Circuit Cellar -- worth it!) written by Rich LeGrand who works for Charmed Labs (who, as it turns out make some pretty cool robot things -- check out their site -- really) .

The paper make reference to the idea of using Back EMF to control a motor. The great thing about it is that you don't need to put any extra stuff on the motor to get PID control. At the Charmed Labs site I found this video that dropped my jaw.

If you want to learn more about how it works, look at this link from another cool robot website, Acroname.com. I think they really do a pretty good job of making the concepts understandable.

Anyway, I think that some smart person at a company that makes stuff for FIRST robots (IFI, AndyMark, Radio Shack, etc.) could make a mint and, more importantly could do all of us FIRST robot builders a huge favor, if they made an Victor-like product that had PID motor control via Back EMF sensing built in. Actually, Acroname.com is part of the way there already in that they offer an H-bridge with velocity feedback built in (Yes, it is too wimpy for FIRST it still shows the idea).

Think about it. Right out of the box, you could have robots driving the way robots aught to be driven: in closed loop not open loop mode.

I am not sure I'll be able to sleep at all on Dec. 24th...

...visions of well behaved robots danced in their heads...

Thoughts?

Joe J.