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Unread 22-12-2010, 09:36
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SPAM, the lunchmeat of superheroes!
AKA: Eric Schreffler
FRC #0180 (SPAM)
Team Role: Engineer
 
Join Date: Apr 2002
Rookie Year: 2001
Location: Stuart, Florida
Posts: 561
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Re: Holonomic + gyro/PID

Quote:
Originally Posted by Ether View Post
Yeah, I was wondering if that's what you meant. ...
We used AnyMark swerves and had about 330deg of rotation before we would get wire wind-up and pull the connectors apart. So we calculated a "keepout" zone based on whether the wheels were commanded forward or reverse. If your current steering request put you in the keepout zone, then flip the wheel and reverse the wheel direction. We used a -180 < 0 < 180 compass for the steering calculations.

Hurdle #1 was getting the angle bookkeeping right.

However, this could produce a "shopping cart" shuck in the steering, as we tried to also use a field-centric stick, and the driver commanded forward and reverse near the keepout.

I finally concluded that you need to track the last pass steering command and bookkeep a 180deg reverse direction +/- a ...say...10deg band. If your current steering request put you in that band, then what you really wanted to do was reverse wheel direction. Then you could compare this new commanded steering angle and wheel direction to your keepout.

I never got to try this. After the Florida Regional, we reverted to robot-oriented sticks and finished the season with them.
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