Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
1997-07-25
2002-05-07
Neyzari, Ali (Department: 2752)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S036010, C369S178010
Reexamination Certificate
active
06385142
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a library device for automatically loading, unloading, keeping, recording data in, reproducing data of, etc. storage media, to a position control device for obtaining position information of a mechanism unit required for transporting storage media and determining a stop position, and to a method thereof.
2. Description of the Related Art
A library device today is used as, for example, a jukebox. It automatically performs loading/unloading, keeping, recording data in/reproducing data of, etc. storage media. Optical disks, MTs (Magnetic Tapes), CD-ROMs (Compact Disk-Read Only Memories), etc. are used as the storage media.
The library device normally comprises a cartridge access station (CAS) for loading/unloading storage media, a plurality of cells for storing the storage media, a drive unit for recording data in/reproducing data of a storage medium, and an accessor for transporting the storage medium between each of the components. The accessor comprises a hand unit for holding a storage medium, a picker mechanism unit (picker unit) for moving the hand unit holding the storage medium backward and forward, and a Y-axis mechanism unit (Y unit) for moving the picker unit upward and downward.
FIG. 1A
shows a picker unit and its peripheral hardware in a conventional optical disk library device. In this figure, a storage medium
1
, cell
2
, picker unit
3
, and a hand unit
4
, are depicted as a top view; gears
8
,
9
, and
10
are depicted as a side view; and a driving unit
11
, move amount detecting unit
12
, controlling unit
13
, and a storing unit
14
are depicted as a block diagram. The picker unit
3
comprises pulleys
5
and
7
, and a belt
6
arranged between the pulleys
5
and
7
.
An MPU (Micro Processing Unit)
20
included in the controlling unit
13
performs feedback control of the driving unit
11
according to a program stored in a ROM (Read Only Memory)
21
in the storing unit
14
. The driving unit
11
includes a picker motor
15
, power amplifier
16
, and a D/A converter
17
. The motor
15
is driven according to a control signal from the MPU
20
, and rotates the gear
10
. As a result, power is transmitted to the pulley
7
via the gears
8
and
9
.
When the pulley
7
rotates, the hand unit
4
holding the storage medium
1
moves backward and forward, and the fingers of the hand unit
4
open/close as the hand unit
4
moves backward and forward. A section during which the fingers are closed (closed section), and a section during which the fingers are open (open section) are included in a stroke of the hand unit
4
. The MPU
20
controls the hand unit
4
in order to stop it in each of the sections. The hand unit
4
holds or releases the storage medium
1
in the cell
2
according to a combination of the sections.
FIG. 1B
shows a load end at which a rotary motion of the motor
15
is converted into a linear motion of the hand unit
4
. In this figure, a gear
8
′ is securely disposed on the rotation shaft of the gear
8
. Rotation is transmitted to the pulley
7
via a gear
7
′ engaging with the gear
8
′. A rotary motion of the pulley
7
is converted into a linear motion of the belt
6
, which moves the hand unit
4
backward and forward. In this case, the gear
7
′ securely disposed on the rotation shaft of the pulley
7
corresponds to the load end.
FIG. 1C
shows the position at which the hand unit
4
stays at the back end of its entire stroke (home position).
FIG. 1D
shows the position at which the hand unit
4
stays at the front end of its entire stroke (empty position). The fingers of the hand unit
4
are closed at the home position shown in
FIG. 1C
, and are open at the empty position shown in FIG.
1
D.
FIG. 1E
shows the closed section during which the fingers are closed, while
FIG. 1F
shows the open section during which the fingers are open. For the control of the picker unit
3
, it is vital to stop the hand unit
4
with high accuracy at the position where the fingers are closed or open, which is close to the center of each of these sections.
The move amount detecting unit
12
comprises a two-phase (A- and B-phase) encoder
18
, and an up-and-down counter circuit
19
. The MPU
20
reads the value obtained by counting the number of pulses output from the encoder
18
by the up-and-down counter
19
, thereby obtaining the amount of a move in the backward and forward directions of the hand unit
4
.
An arbitrary encoder such as an optical encoder, magnetic encoder, etc. can be used as the encoder
18
, which is a sensor for detecting a rotation angle of the motor
15
. An encoder using a photo-interrupter is shown in
FIG. 1G
as an example. In
FIG. 1G
, the encoder
18
comprises a slit plate
22
which is securely disposed on the rotation shaft of the motor
15
, and a photo-interrupter
23
peripheral to the slit plate
22
.
The slit plate
22
has slits at predetermined intervals as shown in FIG.
1
H. As the motor
15
rotates, two beams of light of A and B phases of the photo-interrupter
23
pass through the slits, or are interrupted by the slit plate
22
. Each of output signals of the A and B phases of the photo-interrupter
23
becomes ON when a beam of light passes through, while it becomes OFF when the beam of light is interrupted. In this way, these output signals become pulse signals which cycle between ON and OFF.
The rotation angle of the motor
15
is obtained according to the number of pulses shown in
FIG. 1I
, and the corresponding amount of a move of the hand unit
4
is estimated. Additionally, there is a relative difference between an A-phase pulse and a B-phase pulse. The direction of the rotation of the motor
15
is determined according to the direction of this difference. If the direction of the rotation of the motor
15
is determined, the direction of the corresponding move of the hand unit
4
can be obtained.
However, since only a relative amount of a move can be obtained from the value of the up-and-down counter
19
, the MPU
20
resets the up-and-down counter
19
at the home position shown in FIG.
1
C. Thereafter, the MPU
20
controls the picker unit
3
using this position as a home reference, without resetting the counter value.
To reset the up-and-down counter
19
, the MPU
20
slowly drives the hand unit
4
backward so as not to apply a load to the picker unit
3
, when the device is powered up, verifies a position at which the counter value remains unchanged for a predetermined amount of time or more, and resets the up-and-down counter
19
at that position.
To move the hand unit
4
from the home position to the closed position shown in
FIG. 1E
, the MPU
20
must have the absolute count value of the closed position based on the reset value of the home position, as the information for specifying that position. This is similar to the case in which the hand unit
4
is moved to the open position shown in FIG.
1
F.
A conventional library device stores the count values for specifying the length of the entire stroke shown in
FIG. 1D
, the closed position shown in
FIG. 1E
, and the open position shown in
FIG. 1F
, in the ROM
21
as design values, and controls the picker unit
3
using these values. Assuming that the design value of the home position shown in
FIG. 1C
is “0”, the design values of the positions shown in
FIGS. 1D
,
1
E, and
1
F are respectively 211, 192, and 206.
FIG. 1J
shows a Y unit and its peripheral hardware in a conventional optical disk library device. A Y flag
38
, Y sensor
39
, driving unit
40
, move amount detecting unit
41
, controlling unit
42
, and a storing unit
43
, as shown in
FIG. 1J
, are practically included in a library device
31
. The Y unit comprises pulleys
35
and
37
, and a belt
36
arranged between them, Y flag
38
, and a Y sensor
39
.
An MPU
49
included in the controlling unit
42
performs feedback control of the driving unit
40
, by using a non-volatile RAM (Random Access Memory)
50
′ according
Fujitsu Limited
Greer Burns & Crain Ltd.
Neyzari Ali
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