Your Arduino Balancing Robot (YABR)

Not every gyro is mounted 100% level with the axis of the robot. This can be cause by misalignments during manufacturing of the breakout board. As a result the robot will not rotate at the exact same spot and starts to make larger and larger circles.

To compensate for this behavior a VERY SMALL angle compensation is needed when the robot is rotating.

Find the followin line in the robot program and uncomment it by removing the two dashes:

//angle_gyro -= gyro_yaw_data_raw * 0.0000003;

Try 0.0000003 or -0.0000003 first to see if there is any improvement.