ESTIMATOR-BASED RUNOUT COMPENSATION IN A DISK DRIVE

In a disk drive controller, a head position servo compensates for repetitive runout disturbances arising from displacement of the center of the concentric data storage tracks from the axis of rotation of the disk. An estimator model is provided which includes first and second runout parameters for emulating the sinusoidal runout disturbance at a period that is the same as the rotational period of the disk. The runout parameter values generated from the model are stored in a reference table and used during read/write operations to adjust compensator-generated command signals in order to compensate for repetitive runout. Alternatively, an estimator including the runout parameters is operated in real time to provide estimated state signals as feedback signals for the servo system.