公开(公告)号：JPS6383976A

公开(公告)日：1988-04-14

申请号：JP22907286

申请日：1986-09-27

Applicant: SONY CORP

Inventor： MUTO TAKAYASU ,  TADA HARUTAKA

IPC: G11B21/10 ,  G11B21/08

Abstract: PURPOSE:To suppress the extent of overshoot of a head to a small value by gradually raising the level of the position reference used for accurate positioning control in accordance with elapse of time after rough positioning control using a head position detecting sensor. CONSTITUTION:After the head is roughly positioned to a target rack on the basis of a detection output TOB of a head position detecting sensor 7, track position information preliminarily recorded on a magnetic disk 4 is picked up by the head 1. The extent of deviation of the head 1 from the center of the target track is detected on the basis of this track position information FIS, and the level of a position reference REF 3 used for accurate positioning control is gradually raised from a prescribed level according as the time elapses. Thus, the extent of overshoot of the head is held down to a small value to prevent runaway of a head arm.

公开(公告)号：JPH01220274A

公开(公告)日：1989-09-01

申请号：JP4659288

申请日：1988-02-29

Applicant: SONY CORP

Inventor： MUTO TAKAYASU ,  FUJINAWA AKIRA ,  YAEGASHI AKIRA ,  NAKANO KATSUHIRO ,  TADA HARUTAKA ,  IKEDA KATSUMI

IPC: G11B21/10

Abstract: PURPOSE:To perform tracking control with high accuracy by performing the tracking control of a magnetic head on a recording track formed on each disk surface corresponding to the correction quantity of reference tracking. CONSTITUTION:Magnetic head position detecting means 6 and (15-19) which output the position detection signal SP of the magnetic heads (4A-4D), and a magnetic disk 3 on whose disk surfaces (3A-3D) servo tracks are formed are provided. Reference tracking correction quantity detecting means 4A-4D, 35, 40, 41, 43, 44, 48, 49, 50, and 51 to perform the positioning of the magnetic heads (4A-4D) on the servo tracks based on the position detection signal SP and to detect the correction quantity of the reference tracking at every disk surfaces (3A-3D) are provided. The tracking control of the magnetic heads (4A-4D) are performed on the recording tracks formed on the disk surfaces (3A-3D) corresponding to the correction quantity of the reference tracking. In such a way, it is possible to prevent a tracking error from being generated, and to perform the tracking control with high accuracy.

公开(公告)号：JPS63154916A

公开(公告)日：1988-06-28

申请号：JP30292586

申请日：1986-12-19

Applicant: SONY CORP

Inventor： SETO HIDEKAZU ,  TADA HARUTAKA

IPC: G11B21/08 ,  G01D5/34 ,  G01D5/347 ,  G01D5/36

Abstract: PURPOSE:To eliminate a speed detection error and the phase shift between outputs, by obtaining triangular wave-shaped outputs different in a phase from each other by the relative movement of a scale and a sensor and adjusting the amplitudes of the outputs so as to bring differential values to predetermined values. CONSTITUTION:Triangular wave-shaped outputs SA-SD are obtained by the relative movement of a scale having a predetermined structure and a sensor. The differential wave forms of said outputs are visually observed and adjusted in amplitude using a variable resistor so that the differential values in the vicinity of detection points XA-XD exceeding predetermined voltage upwardly to the right become prescribed values. A first, when each output is matched with output SA1 made obtuse in a wave- form in the vicinity of the max. value and the min. value, the differential wave-form DSA1 thereof becomes a square wave having large amplitude dl. Amplitude d2 is adjusted to the amplitude d1 of an ideal triangular wave and all of the outputs SA-SD are processed in the same manner. By this constitution, even when the output S is distorted, the moving speed error in the vicinity of the detection point X can be removed. When SA supposed to originally possess phase difference of 90 deg. is shifted from SB1, the wavelength of SB1 is raised as a whole to correct the phase difference of detection points XA, XB2 to 90 deg..