Collecting speed rate and acceleration

[Vulpo]

I am using the I2C library and the source code on github (https://github.com/jrowberg/i2cdevlib/tree/master/Arduino/MPU6050) to collect the yaw, pitch and roll fused from the gyrometer and accelerometer outputs:

        accelgyro.dmpGetQuaternion(&q, fifoBuffer_1);
        accelgyro.dmpGetGravity(&gravity, &q);
        accelgyro.dmpGetYawPitchRoll(ypr, &q, &gravity);

 

So I have two questions:

 

1) I have read that the values above are calculated by fusing the output from the accelerometer and the gyroscope. In this case, I was wondering what is the used algorithm to calculate these way, pitch and roll ?

 

2) Also, I would like get the acceleration from the accelerometer in m²/s and the angle speed from the gyrometer in °/s. What function should I call or what should I do to get these values? dmpgetGyro() and dmgGetAccel() don't give me correct values: I am adding the measured value to the last measure, but if I move my arduino by 90° it outputs 50° instead, and even if I hold still in the position it slowly decreases/increases back to zero.

 

I am truely desesperated on this one. I really need my second question to be answered. I am read the documentation and the datasheet many times but can't get it work properly.