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Unread 23-12-2010, 00:50
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Dave McLaughlin Dave McLaughlin is offline
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Re: Holonomic + gyro/PID

Quote:
Originally Posted by Ether View Post
Do you know where they positioned the discontinuity?

I'm certainly not recommending this, but suppose for example they located it at the 12 o'clock (straight-ahead) position. I can imagine a lot of weird wheel movement going on when trying to drive straight ahead with small directional changes. So I wonder where's the best place to put it. Perhaps it depends on the game played played.

Seeing as no one else from Team 1983 has replied, I think I will speak up from the shadows as a Skunkworks alum.

We positioned the potentiometers such that the discontinuity was facing toward the rear of the robot as was mentioned by the team member from 3123. The pots we were using had a 20 degree dead band, so, to address the issue of having unlimited mechanical rotations possible but only about 340 degrees of sensing range we implemented the "wheel flip power change" also mentioned by the astutely informed member of 3123.

However, prior to competing in the World Championships that year, out team decided to make a switch to MA3 magnetic absolute encoders. As the driver that year, I can tell you that there was a noticeable change in performance and handling. In addition, I can also say with much certainty that had we been playing on a carpet field, the method we used with the potentiometers would not have yielded any positive success.