Quote:
Originally Posted by vrcprogrammer
This is the exact reason I am trying to use the follower wheels, but I would like a way to use the gyro/ultrasonics, to check the data, is this needed, or are the followers accurate enough?
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As far as an accurate gyro, the
navX MXP plugs into the RoboRIO MXP port, features automatic gyro/accelerometer calibration and sensor fusion, and has a yaw drift of about 1 degree per minute when moving (.2 degrees/minute when still) - which exceeds the quality typically achievable w/the gyro in the Kit of Parts. The navX MXP is being used by many teams for accurate field oriented drive and many are able to get it working in a few hours including installation. The navX MXP interfaces to the RoboRio via several protocols including SPI, and has RoboRio libraries in C++, Java and LabView, as well as sample program code, a 3d-printable enclosure and it's open source hardware/software. Please feel free to send me a private message if you have any questions about that.
I think it'd be helpful and educational for many FIRST teams if there were to be a documented project (w/hardware diagram, sample code and statistical results) which details accuracy findings w/the localization approach using encoders and follower wheel you're looking into. If you're interested in taking on that scope of a project, I'd be happy to give you a navX MXP board for free that you can use for this work.
I realize this may not work because you're asking about VEX, but if it sounds interesting to you let me know, and I can try to help w/some advice on getting it to work on a Vex robot.
P.S. I was speaking this year with a mentor on the "Thunder Down Under" (team 3132 from Australia, they made it to Einstein this year), and they were using a similar approach (encoders for X/Y displacement, navX MXP for rotation); I don't have any statistics on how well that worked, but I know it's been attempted and believe it appears promising. Of course, it all comes down to your accuracy requirements, as Ether said earlier....