Dear Mehdi,
As discussed in the following forum topic: Oscillation in local axial wind component and AOA, loads in the rotating frame due to yaw error, shear, turbulence etc. show up as harmonics of the rotor speed (1P, 2P, 3P, etc.), but loads in the fixed frame show up as harmonics of 3-times the rotor speed (0P, 3P, 6P, etc.). While the mean blade-pitch angle is controlled to regulate rotor speed (or power), cyclic blade-pitch control attempts to oscillate the blade-pitch angle about the given mean angle to reduce harmonic loads. Normally cyclic blade-pitch control is targeted at 1P in the rotating frame (also reducing 0P and 3P loads in the fixed frame), but sometimes higher harmonics are also controlled through higher-frequency cyclic-pitch action.
Best regards,