JPS62262283A - Head speed control system - Google Patents

Abstract

PURPOSE:To always move a head at correct speed, by measuring an error in a speed detector, etc., with a rotary disk shaped storage device itself, and correcting a targeted speed signal. CONSTITUTION:The interval of a pulse that is the output of a track cross detector 5 is time-counted by a timer means 12, and the speed of a head 3 is counted from the number of recording tracks crossed by the head 3, and a time required for that, while a targeted speed is kept at a regulated value level. And the targeted speed is corrected on the basis of a calculated result. Thus, since the rotary disk shaped storage device itself corrects the speed detection error of the head 3 in a field, an adjustment at a manufacturing time is made unnecessary, and also, change due to change in the lapse of time of a circuit element, or peripheral circumstance can be absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head speed control system for a rotating disk storage device such as a magnetic disk device used as a peripheral storage device for a computer.

[Conventional technology]

In the conventional head speed control system, as shown in FIG.
Speed control when moving the head 3 between 2] ] 1
is done as follows. The position of the head 3 on the disk 1 is detected by a position detector 4 using well-known means such as surface servo information or an encoder. The output of the position detector 4 shows a specific voltage (for example, zero volts) when the head 3 is directly above the recording track, and using this, the head 3 can be moved from the recording track where the head 3 is located. A track crossing detector 5, which outputs a pulse every time the head crosses the recording head from the edge of the position detector 4 when moving to another recording track, is composed of a comparator and some logic circuits.

CPσ6 reduces the number of remaining recording tracks to the target recording track that the head 3 should reach by one each time it receives one output pulse from the track crossover detector, and refers from the ROM to a target speed signal corresponding to the number of remaining recording tracks. Outputs 9 people in a tough manner. DA converter 7 is cp
The target speed signal generated with σ6 is converted into an analog value.

On the other hand, the speed detector 8 detects the speed of the head 3 by differentiating the output of the position detector 4 or the like. The output of the DA converter 7 and the output of the speed detector 8 are subtracted by a subtracter 9 to give an error between the target speed and the actual speed of the head 3. This error is input to the actuator drive circuit 10 and the head 3 is moved by the actuator 11. In this way, the head 3 moves according to the target speed stored in tOM in advance.

[Problem that the invention seeks to solve]

In such a conventional configuration, the output voltage of the speed detector 8 is
Although there is an error with the actual speed of the head due to an error in the conversion gain of the position detector 4 and speed detector 8, the target speed signal output from the DA converter is information fixed in the ROM. Therefore, the actual speed of the head 3 will vary with respect to the same target speed due to variations in the external environment such as temperature and supply voltage, and variations in electronic elements. This changes the time required for head movement (hereinafter referred to as access time), which is an important performance index in a rotating disk storage device. Furthermore, assuming that the detection error of the speed detector is ±10%, in order to achieve the access time listed in the specifications, the target speed must be set in the device with the largest speed → voltage conversion gain determined by the position detector and speed detector. At this time, in the device with the smallest conversion gain, the head moves at a speed 20 inches greater than in the former. This disturbs the transient behavior of the head as it reaches and positions itself on the desired recording track, and in extreme cases it disturbs the transient behavior of the head when it reaches the desired recording track and positions itself on that recording track, and in extreme cases it disturbs the transient behavior of the head when it reaches the desired recording track and positions itself on that recording track. The head will stop. In order to avoid this, it is necessary to adjust the conversion gain for each device in order to absorb variations in electronic elements and eliminate errors in the speed detector, and also to adjust the conversion gain for each device. It is necessary to design such that the conversion gain does not change with respect to fluctuations, and in either case, the cost tends to be a concern.

The present invention solves these conventional problems and provides a highly reliable and inexpensive rotating disk storage device that does not require external adjustment.

[Means for solving problems]

The present invention includes a rotating disk, a head for writing and reading information on the disk, an actuator for moving the head with respect to a large number of deployment tracks on the disk, and a position detector for detecting the position of the head. a track crossing detector that generates a pulse each time the head crosses the recording track; and a track crossing detector that receives the pulse and counts the number of remaining recording tracks until reaching the target recording track, and measures a target speed generator that generates a target speed to be followed; a speed detector that detects the speed of the head;
In the co-rotating disc storage device R, which includes a subtracter that subtracts the target speed and the output of the speed detector, and an actuator drive circuit that receives the output of the subtracter and drives the actuator, the track crossing The head speed is determined from the number of recording tracks crossed by the head and a certain amount of time while the target speed is constant. is calculated as a Fit number, and the target speed is corrected based on the result of the calculation.

[For production]

According to the above configuration of the present invention, the rotating disk storage device itself measures errors in the speed detector, etc., and corrects the target speed signal, thereby making it possible to always move the head at the correct speed. .

〔Example〕

FIG. 1 is a diagram showing a circuit configuration of an embodiment of the present invention.

A clock means 12 is added to the conventional system shown in FIG.

FIG. 2 shows changes over time in the target speed signal and the output of the speed detector 8 when the head 3 is moved using the configuration shown in FIG.

Assuming that the target speed signal stored in the ROM is as shown by the solid line in FIG. 2, the output voltage of the speed detector 8 follows the target speed signal as shown by the broken line in FIG.

In this embodiment, gain errors of the position detector 4 and speed detector are corrected as follows. First, as shown by the solid line in FIG. 3, the maximum speed vm when moving the head 3 normally
cpty6 outputs a target speed signal corresponding to bar of ax. Then, the head 3 moves so that the output of the speed detector 8 becomes the broken line in FIG. At this time, the number N of recording tracks crossed by the head in a suitable section included in the section C where the speed is constant, the dead time Tt- required for this, the output pulse of the track crossover detection circuit 5 and the clock circuit 12 are determined to be 0.
PU6 counts. When the pitch of the recording track is P, the actual speed of the head 5 in a constant speed section is calculated as V=PM/T. Since the target speed in this section is Vmax/3, the actual speed of the head 3 (P
N/T ) is the speed (Vmax
/3) is 3PN/(T X Vmax) times. This is the gain difference between the position detector 4 and speed detector 80.

Therefore, the target speed signal stored in the ROM is 3PN
Multiply it and output it to the DM converter from K 61r
By excluding the gain error mentioned above, the actual speed of the head 3 can be made to match the original design value.

In this embodiment, the procedure for determining the gain error and determining the correction constant described above is performed once when the rotating disk storage device is started up, and is further performed approximately once every hour to calibrate changes in the gain error due to changes in ambient temperature, etc. This is done at a rate of . The correction constant thus obtained is multiplied by the target speed value when the head moves before the CPU outputs the target speed signal referenced from the ROM to the DA converter. When the head speed is high and the time to go from one recording track to the next is short, there is not enough time for the above calculation, so the target speed signal is updated every other recording track. ing.

〔Effect of the invention〕

In this way, in the present invention, since the rotating disk storage device itself corrects head speed detection errors in the field, it is no longer necessary to perform D4 adjustment during manufacturing, and it also eliminates changes over time in circuit elements and changes due to the surrounding environment. This makes it possible to provide a highly reliable rotating disk storage device at low cost.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an apparatus for realizing an embodiment of the head speed control method of the present invention. FIGS. 2 and 3 are diagrams for explaining a head speed correction procedure according to an embodiment of the head speed control method of the present invention. FIG. 4 is a diagram explaining a conventional head speed control method. Time chart 2

Claims (1)

[Claims] a rotating disk, a head for writing information on and reading information from the disk, an actuator for moving the head with respect to a large number of recording tracks on the disk, and a position detector for detecting the position of the head; A track crossing detector that generates a pulse each time the head crosses the recording track, and a track crossing detector that receives the pulse and counts the number of remaining recording tracks until the target recording track is reached, and the speed of the head should follow. a target speed generator that generates a target speed; a speed detector that detects the speed of the head; a subtracter that subtracts the output of the speed detector from the target speed; A rotating disk storage device having an actuator drive circuit that drives an actuator, the rotating disk storage device having a timer for timing an interval between the pulses that are output from the track crossover detector, and the target speed having a constant value. A head speed control method characterized in that the speed of the head is calculated from the number of recording tracks crossed by the head and the required time, and the target speed is corrected based on the result of the calculation.