Acceleration feedforward control against rotational disturbance in hard disk drives

We have developed an acceleration feedforward control fur hard disk drives by using dual piezoelectric accelerometers. The dual accelerometers detect angular acceleration in the hard disk drive (HDD) and compensate for its negative effects. For optimum compensation we introduced the use of a phase compensation filter (PCF). Using this controller, the rejection capability against rotational disturbance is improved and HDD performance does not decrease even under the severest conditions: for example, in a disk array system that has the severest mechanical interaction between HDDs