[DanielHa]

We are using a well tuned PID loop on the angle returned by the navX in order to turn accurately. An issue that we ran into, which I think might explain what you described (your code working only 9/10 times), is that at certain absolute angles, if you simply add or subtract 180 (or in your case the slightly altered values), then you might get a value which is outside the range of the navX. We use the navX getFusedHeading() method as opposed to the getYaw() method, so I'm not sure how the values returned by these two methods differ. But essentially, since the navX returns values modulo 360 (for the getFusedHeading() method), if you want any value you calculate to be within the range 0-360, you can perform some mathematical modulo function on it. For instance, ((desired angle + 360) % 360) will map any angle greater than -360 to an angle between 0 and 360. On the other hand, (((desired angle + 540) % 360) - 180) will map any angle greater than -360 to an angle between -180 and 180 if you would prefer that. You can work out what would be best for you, but I hope this might help explain your issue.

In regards to PID, I would highly suggest, like most everyone else replying here, that you look into it. It is fairly simple and can drastically increase the accuracy, speed, and smoothness of your turning.

EDIT: I actually looked at the reference, and found that getYaw() returns values between -180 and 180. Notice that if it is greater than 0, you subtract 227. This would suggest that you could possibly be trying to turn to the angle -226, which the getYaw() method will never return. Instead you might want to take the angle and map it to -180 to 180 using a function like the second one I described. This way, -226 will be turned into +134, which is a value which will work with what the navX returns.