Thread: IMUs
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Unread 17-01-2016, 13:52
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FRC #0330 (Beachbots)
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Re: IMUs

Quote:
Originally Posted by otherguy View Post
ADXRS453 Gyro ($76 eval board from digikey). We used this last year with great success. I believe a number of other teams have used this sensor as well. Pretty sure it's what's on the Spartan MXP board that came out this year. We have observed about 1-2 degrees of drift over the duration of the match. Our code to interface to it. This is a 1 axis gyro, so it's just going to be able to provide heading. And like other rate gyros, it requires calibration to take place when the robot is sitting still. We've written code to detect when the calibration is innacurate and force a re-cal. If you go this route, pay attention to the method supporting calibration inside of the Robot class.
Every team is getting an ADXRS450 as part of the 2nd first choice. See http://firstchoicebyandymark.com/fc16-000. FIRST also added libraries to wpilib.


Quote:
Originally Posted by otherguy View Post
For reference, the way we approach this problem on our team is through a combination of a camera and gyro.
  • The drive team (or auto code) gets the robot to the approximate location we want to shoot from on the field.
  • vision code identifies where we are relative to the goal (distance and angular displacement)
  • a gyro is used to correct for angular displacement by rotating the chassis to center our shot on the goal
  • in the past we have corrected our distance error by adjusting the RPM of our shooter, not by adjusting the position of our drivetrain on the field
We've also used this process. The year it was most useful was 2012, going for the center bridge first, then shooting. See an example of our autonomous here: http://www.thebluealliance.com/match/2012new_qm33

Last edited by Joe Ross : 17-01-2016 at 14:30.