Digital servo control system for data recording disk file with improved saturation modeling

摘要

The present invention relates to a read / write head in a data recording disk file in a manner that uses a voice coil motor (VCM) to position the head using improved modeling of the servo system in a saturated seek mode. To a digital control servo system. The VCM has a characteristic torque factor that varies with a predetermined relationship, headroom age, and temperature of the head position, and the servo system mainly has a low frequency variation of the current of the VCM in the saturation search mode at the maximum level of current. The servo system calculates an estimated VCM control value representing the VCM current, calculates estimates of the state of the VCM including the head position and the speed, calculates an algorithmic model, The head position and speed predicted value are calculated. Improved modeling changes the algorithmic model to reflect the actual maximum current level in saturated search mode and the actual torque factor of the VCM, not the nominal torque factor and nominal VCM current. The preferred method includes scaling factors that represent the ratio of the measured torque factor to the nominal torque factor to scale the model and scaling factors that represent the ratio of the measured maximum current level to the nominal current level scaling factors to calculate the predicted state of the VCM in the saturated search mode from the scaled model and current state values.