Abstract: In a head loading/unloading type disk apparatus, accurate velocity feedback control is implemented by correcting any error in a VCM velocity detection value, which is caused by a temperature change or the like. At the start of loading control for loading a head from a ramp onto a disk, a carriage is pushed against an outer-periphery stopper to set the actual velocity of a VCM to zero. In this state, a VCM velocity detection value detected by a VCM velocity detection circuit is read out. On the basis of this velocity detection value, calibration for correcting the relationship between the VCM current value and the VCM velocity detection value is performed. In the period of head positioning control after the loading, an operation using a timer is periodically performed in which the carriage is pushed against an inner-periphery stopper, the calibration is reexecuted, and the head is returned to the original head position.

Abstract: In a head loading/unloading type disk apparatus, accurate velocity feedback control is implemented by correcting any error in a VCM velocity detection value, which is caused by a temperature change or the like. At the start of loading control for loading a head from a ramp onto a disk, a carriage is pushed against an outer-periphery stopper to set the actual velocity of a VCM to zero. In this state, a VCM velocity detection value detected by a VCM velocity detection circuit is read out. On the basis of this velocity detection value, calibration for correcting the relationship between the VCM current value and the VCM velocity detection value is performed. In the period of head positioning control after the loading, an operation using a timer is periodically performed in which the carriage is pushed against an inner-periphery stopper, the calibration is reexecuted, and the head is returned to the original head position.

Abstract: In a head loading/unloading type disk apparatus, accurate velocity feedback control is implemented by correcting any error in a VCM velocity detection value, which is caused by a temperature change or the like. At the start of loading control for loading a head from a ramp onto a disk, a carriage is pushed against an outer-periphery stopper to set the actual velocity of a VCM to zero. In this state, a VCM velocity detection value detected by a VCM velocity detection circuit is read out. On the basis of this velocity detection value, calibration for correcting the relationship between the VCM current value and the VCM velocity detection value is performed. In the period of head positioning control after the loading, an operation using a timer is periodically performed in which the carriage is pushed against an inner-periphery stopper, the calibration is reexecuted, and the head is returned to the original head position.

Abstract: In a magnetic disk drive, in the case of unloading a head, a carriage receives a driving force of a voice coil motor as a controlled object so as to drive the head, and then, a speed &ohgr; of the carriage is detected from a back electromotive voltage generated in a coil of the voice coil motor. A ramp collision discriminator makes a decision that the head collides with the ramp on the basis of at least one of the speed &ohgr; and a controlled manipulated variable fed back to the voice coil motor as being a controlled object from a speed controller. In the case where a ramp collision is discriminated, a gain changeover switch is controlled so that a speed feedback gain of the speed controller is changed into a high gain side. Therefore, when the head collides with the ramp, it is possible to prevent a great reduction of the carriage moving speed and a temporary stop of a carriage moving operation, and thus, to realize a stable head unload operation.

Abstract: In a head loading/unloading type disk apparatus, accurate velocity feedback control is implemented by correcting any error in a VCM velocity detection value, which is caused by a temperature change or the like. At the start of loading control for loading a head from a ramp onto a disk, a carriage is pushed against an outer-periphery stopper to set the actual velocity of a VCM to zero. In this state, a VCM velocity detection value detected by a VCM velocity detection circuit is read out. On the basis of this velocity detection value, calibration for correcting the relationship between the VCM current value and the VCM velocity detection value is performed. In the period of head positioning control after the loading, an operation using a timer is periodically performed in which the carriage is pushed against an inner-periphery stopper, the calibration is reexecuted, and the head is returned to the original head position.

Abstract: In a head loading/unloading type disk apparatus, accurate velocity feedback control is implemented by correcting any error in a VCM velocity detection value, which is caused by a temperature change or the like. At the start of loading control for loading a head from a ramp onto a disk, a carriage is pushed against an outer-periphery stopper to set the actual velocity of a VCM to zero. In this state, a VCM velocity detection value detected by a VCM velocity detection circuit is read out. On the basis of this velocity detection value, calibration for correcting the relationship between the VCM current value and the VCM velocity detection value is performed. In the period of head positioning control after the loading, an operation using a timer is periodically performed in which the carriage is pushed against an inner-periphery stopper, the calibration is reexecuted, and the head is returned to the original head position.

Abstract: Disclosed is a head loading/unloading type disk drive of retracting a head to a ramp by a reserve power supply upon power down of a main power supply. An unloading control system drives a VCM using a low-level voltage from the reserve power supply until the head reaches the ramp immediately upon power down of the main power supply. After the head reaches the ramp, the system applies a high-level voltage from the reserve power supply. The reserve power supply is made up of a rectifier for converting the back EMF of an SPM into a DC voltage. When a retract circuit detects power down of the main power supply, the DC voltage from the rectifier is limited to a low-level constant voltage by a constant voltage circuit, and applied to the VCM. When a ramp collision determining circuit determines collision of the head against the ramp, it controls the voltage applied to the VCM from the low-level voltage to a high-level voltage.

Abstract: A servo system uses a disk on which two pairs of burst data items A and B and burst data items C and D are prerecorded, and the servo system performs positioning control for positioning a head within a range of a track on a disk. The servo system sets a range of a track to be divided into a first area regarding the track center as a reference position, a second area regarding a boundary position between tracks as a reference position, and a third area regarding a middle position between the reference positions, as a reference position. In the first area, the servo system calculates position information of the head by a first calculation formula using the burst data items A and B. In the second area, the servo system calculates position information of the head by a second calculation formula using the burst data items C and D. Further, in the third area, the servo system calculates an average value of calculation results from the first and second calculation formulas, as position information.