Phi Calculation - Printable Version

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Phi Calculation - Glenn - 10-06-2016 05:02 PM

Hi All--

I've been experimenting with the MPU6050. I've gotten the MPUTeapot demo to work using Jeff Rowberg's libraries. I am wondering why the formula used for phi in the B-Robot code, calculated from the MPU6050's dmp quaternion values:

return (atan2(2 * (q.y * q.z + q.w * q.x), q.w * q.w - q.x * q.x - q.y * q.y + q.z * q.z) * RAD2GRAD);

produces different results than the phi produced by the MPU6050's dmp:

mpu.dmpGetEuler(euler, &q);

Aren't these calculated straight from the quaternion values as well? Any thoughts would be appreciated.

RE: Phi Calculation - JJrobots JP - 10-10-2016 06:42 AM

Hi Glenn
We do not know that Jeff Rowberg's library. We just used the regular transformation from quaternion to euler.