Gyro inconsistencies...

[Jake M]

After two days of testing, I'm pretty sure our gyro gives slightly different output, depending on which direction it's turning. For instance...

Counter-Clockwise
-----------------
1771
1777
1773
1771
1775
-----------------
Clockwise
---------
1802
1796
1800
1806
1800
---------

These are outputs given after resetting the angle to zero and slowly turning the gyro exactly 180 degrees. As you can see, the clockwise direction is quite near perfect, but the other direction is always off. You can also see that both directions are very consistent. If I re-calibrate based on the counter-clockwise direction, then the clockwise direction is consistently off.

I'm not really that worried about 3 degrees, but what I've found is that because of this, when the gyro turns far from zero, it doesn't go back to zero at the same position, and I can easily see that error compounding very quickly, particularly since the gyro seems to be less consistent the faster I turn it, and I doubt the robot will want to turn as slowly and carefully as I am.

Is this really all that strange? Should I just reset the heading to zero whenever I actually need to use it? Should we perhaps invest in a better quality gyro?

Settings and such...
-------------------
ADC Sample Rate of 1600Hz
32 ADC Samples per Update
Deadband set to 16 (Deadband and Bias double when resolution goes from 2048 to 4096)
Using ADXRS150