KR850001460B1 - Driver of coaxial disk pack - Google Patents

Abstract

The driver of a coaxial has a disk pack that includes a servodisk that moves up and down to control access to the head. The device comprises a servo-switching element, which has a switch to selectively output a head position signal; and a position signalselecting element, which as a detecting circuit to determine whether the disk has arrived at a designated level; and a switching circuit.

Description

Coaxial Disk Pack Drives

1 is a structural diagram of a conventional single disk pack drive device.

2 is a diagram showing the structure and head positioning circuit of the coaxial disc pack drive device used in the present invention.

3 is the operation time chart of FIG.

4 is a block diagram of a head position signal discriminating unit and a switching control unit of the coaxial disk pack drive device according to the embodiment of the present invention.

5 is an operation time chart of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial disk pack drive device, and more particularly, to a disk pack drive device having servo disks on upper and lower disk packs, respectively.

The disk pack drive device can directly access any place and information using a rotating body, can be used as a random access file, and replaces a plurality of disk rotating bodies in one unit. Because it can be used, it can have infinite capacity.

A conventional disc pack drive device having a single disc pack includes a disc drive mechanism (such as a drive motor 7) for driving and stopping the disc pack 1 and a recording / playing head 2 as shown in FIG. An access mechanism (linear motor 3, movable arm assembly 4) to be moved and positioned on a desired track, and a write / read mechanism for writing information to or reading information from the disc pack 1 are provided.

Normally, a plurality of disk pack drive devices are connected and controlled from a channel device via a disk pack controller string switch or the like.

The user uses a plurality of disk pack drives as random access files and uses them as data files, user program files, work files, and residences for operating systems (OSs). In this case, two sets are used as one set, and one side is used as a data file for the user and the other as a file for the system (OS). In the case of using two pairs in this manner, if a power supply or a control system is separately provided, it is disadvantageous in terms of materials, space, cost, and the like.

The present applicant has previously proposed a coaxial disk pack driving apparatus which installs a servo disk in each pack by superimposing two disk packs up and down on a coaxial shaft, and accesses the head by the information. As shown in FIG. 2, the upper pack 1 and the lower pack 1 'are installed on the main shaft 8, and the servo disks 5 and 5' are provided on the main shaft 8, respectively, to provide a common power source, Both packs 1 and 1 'are rotated by the drive motor 7 and the recording / playback heads of both packs are controlled by a common access mechanism (linear motor 3 and movable arm assembly 4). 2), (2 ') is moved. The user usually uses the upper pack 1 as the user's data file and the lower pack 1 'as the file for the system (OS).

In this case, one side of the servo disks 5 and 5 'may be provided on both packs 1 and 1' in common. However, due to manufacturing errors, the servo disks 5 and 5 'are slightly inclined from the upper and lower portions of the main shaft 8. In this case, if the servo disks are provided separately, high-precision positioning becomes possible.

Positioning of the recording / reproducing head 2 to the target track is performed by a closed looper servo constituted by an access mechanism such as the linear motor 3 and the positioning circuit shown in FIG. . In order to perform high-speed and high-precision positioning, speed control is performed by the speed mode VM until the target track is approached, and position control is performed by the position mode PM after the target track is approached.

In the speed mode VM, acceleration and constant speed are determined according to a reference speed curve generated by the reference speed generating circuit 10 under the control of a speed loop composed of the tachometer 9, the error amplifier 13, and the power amplifier 14. V) Deceleration is performed in the shortest time.

In the position mode PM, the error amplifier 13 amplifies the position signals obtained from the position detectors 12 and 12 'following the velocity mode VM with the speed and position at the time of mode switching as initial values. After that, the amount of anilog is negatively fed back to the linear motor 3 via the power amplifier 14. Therefore, the linear motor 3 is stable and stops at the point where the position signal becomes O (V). Also in FIG. 2, the position detector 12 generates a position signal from the servo disk 5 of the upper pack and the position detector 12 'generates a position signal from the servo disk 5' of the lower pack. Therefore, these are switched and sent out.

When moving the recording / playback heads 2 and 2 'to a desired track position by a program command, the time required for positioning the heads 2 and 2', i.e., seek time. Depends on the distance traveled, and takes 10ms ms between adjacent track positions and 10ms-100 ms at the maximum distance from the D track to the innermost track position, accounting for the largest proportion of access time.

In the position detectors 12 and 12 ', the position signal (cylinder signal) 15 shown in FIG. 3 (a) and the position pulse (cylinder pulse) 16 shown in FIG. 3 (b) are generated.

A logic level signal (not shown) is generated between a period of ± 15 um before and after the position signal 15 passes through OV, that is, between the lines 17 and 18, and a position pulse ( 16) is generated.

As shown in FIG. 2, the position pulse 16 is input to the reference speed generating circuit 10 from the position detectors 12 and 12 'in the velocity mode VM, and is shown in FIG. One of the reference speed curves 19, 20, and 21 shown is created. FIG. 3 (d) shows the distances that are sequentially reduced by the position pulses. Curves (19), (20) and (21) represent head speeds from track position (0) to P, M, N (P <M <N), respectively. The maximum speed is shown in the vicinity. However, when a failure occurs in the speed detector (electronic) tachometer (9) power amplifier (14) of the head positioning control system, an abnormal current flows in the moving coil of the linear motor (3). , The carriage carrying (2 ') may run over and collide and be damaged. In order to prevent this, conventionally, a speed detector (a method of judging abnormality when the output of the tachometer (9) is at a constant level or only at a constant level when a predetermined time has elapsed since the recording / playing head starts to move is employed. have.

However, this method only detects an abnormality caused by a failure of the speed detector and a failure within a predetermined time, and cannot detect a case where the servo information is abnormal in other cases.

In addition, when it is determined that there is an abnormality, there is no conventional control method, and there is no way to return the head to its original position at low speed, or to cut the control system and leave it in a free state.

SUMMARY OF THE INVENTION An object of the present invention is to provide a coaxial disk pack driving device capable of preventing runaway of a head mounted carriage by quickly detecting abnormalities in servo information and performing appropriate control in order to solve such a conventional problem. have.

The coaxial disc pack driving apparatus of the present invention determines whether or not the head position signal of the upper or lower pack currently selected is normal or not, and generates a discrimination signal. A head position signal is input to an access control system circuit to perform head positioning.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

4 is a block diagram of a head position signal discrimination unit and a switching controller of the coaxial disc pack driving device according to the embodiment of the present invention.

In FIG. 4, the upper half is a position signal discriminating unit and the lower half is a servo information switching control unit.

Position signals 41 and 42 generated from the upper and lower servo disks 5 and 5 'are inputted to the analog switches 48 and 48'. In a normal operation, a flip-flop ( Since 47 is in the reset state, when the pack select signal 38 (high level "H" or low level "L") opens the EOR gate 400 and the select signal 40 is "L", the upper analog switch is turned on. At 48, the respective contacts of the lower analog switch 48 'are closed.

As a result, the position signals 41 and 42 corresponding to the upper pack 1 or the lower pack 1 'operate the operational amplifier 48 through one of the contacts of the analog switches 48 and 48'. Inputs are made to the control system 50 to access the heads 2 and 2 '. One of the upper and lower position signals 43 is fed back to the position signal discriminating unit and compared with the upper slice level 32 or the lower slice level 33 by the comparators 45 and 45 ', respectively. At this time, when the position signal 43 exceeds at least one of the upper and lower slice levels 32 and 33, the OR gate 340 is opened to display an UP threshold signal (hereinafter referred to as UTH) 34. It is set as "H".

When the seek start signal 31 is input from the host device CPU or the servo controller logic, the monostable multivibrator 44 generates a pulse output 35 having a predetermined time width. When the UTH 34 becomes "H" within the new signal of the pulse output 35 of the monostable multi-vibrator 44, the position signal 43 is judged to be normal, so the up-down switching signal 40 changes to analog. The switches 48 and 48 'are switched to select the position signal 41 or 42 on the opposite side.

5 is an operation time chart of FIG.

FIG. 5 (a) shows the chic star art (signal 31), FIG. 5 (b) shows the (±) slice level 32, 33 and the position signal 43, and FIG. 5 (c) shows the UTH 34 4 (d) is a monostable multivibrator output 35, 5th (e) is a set-up output of flip-flop 46, 5th (f) is a set-up output 39 of flip-flop 47 Are shown respectively.

First, in the normal operation, since the position signal 43 shown in FIG. 5 (b) exceeds the upper and lower slice levels 32, 33, the slice level 32 as shown in FIG. 5 (c) ), UTH 34 becomes " H " for a period exceeding 33). In the period in which the monostable multivibrator 44 is started by the chic star art signal 31 and the output 35 shown in FIG. 5 (d) is "H", the UTH 34 is "H". When rising to the flip-flop 46 is set. When the next UTH 34 rises, the flip-flop 46 is reset because the output 35 of the monostable multivibrator 44 is " L " so that the set output waveform of the flip-flop 46 is fifth (e). Is shown in the figure.

The flip-flop 47 is set when the reset output of the flip-flop 46 is " H " upon rising of the inverted signal of the monostable multivibrator 44. In normal operation, the UTH 34 becomes " H " within the period in which the output 35 of the monostable multivibrator 44 becomes " H " so that the flip-flop 46 is set. On the other hand, when the inverted signal of the output 35 of the monostable multivibrator 44 rises in normal state, since the D-terminal input, that is, the reset output of the flip-flop 46 is "L", the flip-flop 47 Is not set. Therefore, since the set-type output of the flip-flop 47, that is, the position signal start signal 39 maintains the state of "L", the selection signal 40 coincides with the pack selection signal 38.

On the contrary, in the abnormal case, since the output 35 of the monostable multivibrator 44 does not become "H" in the "H" time, the flip-flop 46 is not set. Therefore, since the output at the reset of the flip-flop 46 becomes "H", the flip-flop 47 is set when the inverted signal of the monostable multivibrator 44 output 35 rises.

For this reason, since the position signal start signal 39 becomes "H" at the time of abnormality, the selection signal 40 becomes the value which inverted the pack selection signal 38. As shown in FIG.

For example, when the position signals 41 and 42 are ground shorted, it can be used by switching to the other position signal, so that the runaway of the carriage can be effectively prevented.

As described above, according to the present invention, since the abnormality of the servo information is detected and switched to the servo information on the other side to perform access control, congestion of the head mounted carriage can be effectively prevented.

Claims (1)

In the coaxial disc pack drive device which is provided with the servo disk for controlling head access to upper and lower disk packs, and converts the signal from the upper and lower disk packs, and inputs it to an access control system, the servo switch part and a position are provided. The servo information switching unit includes a switch for inputting a head position signal from the upper and lower disk packs, switching to one of the signals, and selectively outputting a head position signal, and the position signal discriminating unit is inputted from the switch. And a circuit for detecting that the amplitude values above and below the head position signal to reach a predetermined level are provided, and a circuit for switching the switch when a predetermined level is not detected by the circuit. Coaxial Disc Pack Drive.

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