Just did some searching and it look like I'm not crazy after all.
Check out this thread:
http://www.chiefdelphi.com/forums/sh...ad.php?t=55200
Quote:
I'm trying to implement a closed loop controller with the KOP Gyro, and it seems to have a major flaw !!!
The initial symptoms were that if you locked the current heading when the operator stoped turning the bot (joystic returns to detent), the controller would steer the robot BACK about 30 degrees.
I initially suspected my code, but finally I had to start looking at the actual Gyro input. By just wiring the Gyro to a stand-alone RC unit on analog channel 1, I could display the gyro angle whenever it changed.
If I spin the gyro, the heading starts changing immediatly, but when I stop it, the heading changes continue on for almost another SECOND. Once again I suspected my software (maybe overflowing the serial port), so I changed the input to a pot so I could simulate gyro input.
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That is
exactly the problem I am having, and this guy has the same problem with last year's gyro, too.
And here's one of the responses:
Quote:
The KOP gyro has a maximum number of degrees it can turn in one second before it 'overflows' and loses accuracy. To the best of my knowledge, this value is ~85 degrees in one second for the KOP gyro. If you try turning 180 degrees in one second, you will overflow the sensor and drastically lose accuracy. (This is the same as exceeding the +1G acceleration on the accelerometer.)
For use of the gyro with our drive-train on our robot this year, we purchased an additional gyro with a maximum turn-rate of 300 degrees in one second from Spark Fun Electronics. (Which has tons of great sensors, BTW.) Seeing how our drive-train this year is geared for 9 ft/sec at 85% of the CIM motor free speed, the increased turning-rate of this additional gyro was much appreciated.
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Which is what leads me to believe that the 300 dps gyro would solve our problem.
Any thoughts?