JPH05307819A - Library device - Google Patents

Abstract

PURPOSE:To shorten the time for reaching a target position and to prevent the generation of vibration in a cell drum in the case the moment of inertia of the cell drum is not accurately known, in a library device using a cell drum. CONSTITUTION:The value of decelerating torque is set by a means 1 for setting the decelerating torque. A revolving means 3 is controlled by a control part 2 for revolving means in accordance with the value of the decelerating torque set by the means 1 for setting the decelerating torque, and the cell drum 4 is revolved by the revolving means 3. A signal corresponding to the rotational speed of the revolving means 3 is generated by a tachometer 5. A difference between a reference speed at the time of deceleration of the revolving means 3 and the rotational speed of the revolving means 3 is determined from the output signal of the tachometer 5 by a means 6 for calculating a speed error. The value of the torque to be corrected is determined from the output data of the calculating means 6 for speed error by a calculating means 7 for a corrected torque and the value of the torque to be corrected is inputted in the control part 2 for revolving means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a library device,
In particular, it relates to a library device using a cell drum.

A library device is generally known as a peripheral device of a computer. In this library device, a medium (magnetic tape or the like) for recording data as an external storage device of a computer is made into a cartridge and stored in the device, and if necessary, a predetermined cartridge is taken out by using a carrying mechanism to store the data. This is a configuration for performing recording / reproduction processing. In the library apparatus using the cell drum, the cell drum has many storage shelves, and the cartridges are stored in the shelves. When the cartridge is taken in and out, etc., position control is performed to rotate the cell drum and stop it at the target position.

In controlling the position of the cell drum, it is necessary to move the cell drum to a target position more quickly and without vibration.

[0004]

2. Description of the Related Art An example of a conventional library device will be described by taking a device using a motor as a rotating means. The torque T _M generated by the motor that rotates the cell drum is T _M = (J · α
ω) / G + T _C = K _T · I Here, J is the moment of inertia, αω is the angular acceleration, G is the gear ratio T _C is the friction torque, K _T is the torque constant, and I is the motor current. From the above relational expression, generally, in the case of position control in which an object is rotated by a motor and stopped at a certain target position, it is necessary to grasp the inertia moment J of the object and the friction value of the mechanism section. ..

In the device using the cell drum, the driving current corresponding to the moment of inertia J and friction during acceleration and deceleration,
At constant speed, a drive current according to friction is passed through the motor to control the torque of the motor. That is, the required torque is applied so as to exceed the dynamic torque due to the mass and the moment of inertia J.

In the library device using the cell drum,
For example, the number of cartridges is managed, and the inertia moment J is calculated from the weight of the cell drum according to the number of stored cartridges.
The moment of inertia J is calculated by a method such as calculating In a conventional library apparatus using a cell drum, when the cell drum is stopped at a certain target position, a constant deceleration current corresponding to the calculated inertia moment J and friction is applied to the motor during deceleration to control the torque of the motor. ..

[0007]

However, in the library device using the cell drum, the weight of the cartridge varies, and the moment of inertia may not be calculated accurately. For example, in a cartridge magnetic tape library device, there is a difference in weight between cartridge types (long-time type, short-time type), and an accurate moment of inertia may not be calculated even if the number of cartridges is managed.

In the conventional library device using the cell drum, when the inertia moment of the cell drum thus calculated is not accurate, a constant deceleration current is applied to the motor during deceleration based on an inaccurate calculated value of the inertia moment. To control the torque of the motor.
There is a problem that it takes time to reach the target position because it stops before the target, and the cell drum vibrates around this target position until it stops at the target position.

The present invention has been made in view of the above points, and it is possible to shorten the time to reach the target position when the moment of inertia of the cell drum is not accurately known, and to vibrate the cell drum around the target position. It is an object of the present invention to provide a library device capable of preventing the occurrence of the above.

[0010]

FIG. 1 is a block diagram showing the principle of a library device according to the present invention. In the figure, deceleration torque setting means 1 sets the value of deceleration torque. The rotation means control unit 2 controls the rotation means 3 according to the value of the deceleration torque set by the deceleration torque setting means 1, and the rotation means 3 rotates the cell drum 4.

The tachometer 5 generates a signal corresponding to the rotation speed of the rotating means 3. The speed error calculating means 6 calculates the difference between the reference speed and the rotation speed of the rotating means 3 during deceleration of the rotating means 3 from the output signal of the tachometer 5. The correction torque calculation means 7 calculates the value of the torque to be corrected from the output data of the speed error calculation means 6, and inputs the value of the torque to be corrected to the rotation means control unit 2.

[0012]

In the present invention, when the rotating means 3 is decelerated, the rotating means 3 is arranged so that the rotating speed of the rotating means 3 coincides with the reference speed.
Since the torque is corrected, the deceleration can be performed at a predetermined reference speed.

[0013]

FIG. 2 is an external view of a cartridge magnetic tape library device according to an embodiment of the present invention. Same figure (A)
Shows an external view seen from the front side, and (B) shows an external view seen from the back side. 3 is a sectional view of a cartridge magnetic tape library device which is an embodiment of the present invention. The figure (A) shows the sectional view seen from the front side, and the figure (B) shows the sectional view seen from the upper surface. 2 and 3, the same components as those in FIG. 1 are designated by the same reference numerals.

In FIG. 2A, 31 is a cartridge loading section, 32 is a cartridge discharging section, and 33 is an operation panel. In FIG. 2B, 4 is a cell drum, 35 is a cartridge direct loading / unloading door, and 34 is a cartridge direct loading / unloading operation panel.

In FIG. 3, reference numeral 36 denotes an accessor which moves the cartridge 14 between the cartridge loading unit 31, the cartridge discharging unit 32 of the access station 30, the shelf of the cell drum 4, and the magnetic tape drive unit 37. 37 is a magnetic tape drive, which is an accessor 36
Read and write the cartridge magnetic tape mounted by. 38 is accessor 37, access station 3
0, a robot controller that controls the cell drum 4. Three
Reference numeral 9 is a control device for controlling this device from the outside.

When the operator inserts the cartridge 14 into the cartridge inserting section 31 and gives an instruction on the operation panel 33,
The cartridge 14 is stored in a predetermined shelf of the cell drum 4 by the accessor 36. In addition, by instructing with the operation panel 33, the desired cartridge 14 is moved from the shelf of the cell drum 4 stored by the accessor 36.
It can be discharged to the cartridge discharge section 32.

In addition, when a large number of cartridges 14 are loaded or ejected at one time, the cartridge direct loading / unloading operation panel 34 on the rear surface of the apparatus is operated to open the cartridge direct loading / unloading door 35, and one row of 35 rolls is arranged. It can be charged and discharged.

In this apparatus, a designated one of the cartridges 14 stored in the cell drum 4 is attached to the magnetic tape drive device 37 in accordance with a command received from the outside via the control device 39. After the designated cartridge 14 is mounted in the magnetic tape drive device, reading / writing of the cartridge 14 is performed by an external command.

FIG. 4 shows an explanatory view of an embodiment of the present invention.
In the figure, the same components as those in FIGS. 1, 2 and 3 are designated by the same reference numerals. 4 is a cell drum, which has nine shelves for accommodating the cartridges 14 in the circumferential direction, and 35 shelves in each row.
There are 5 volumes. Reference numeral 3 is a motor that is a rotating means, and rotates the cell drum 4 via a gear 17. The gear ratio of the gear 17 is about 150: 1. Reference numeral 5 is a 500-slit two-phase tachometer, which is a tachometer, and is composed of a combination of a photosensor and a slit. The disk having the slits of the tachometer 5 is directly connected to the shaft of the motor 3 and outputs 500 tachometer pulses per one rotation of the motor 3.

Reference numeral 11 denotes a control circuit, which comprises a rotation means control unit 2, a speed error calculation means 6, a correction torque calculation means 7, and a deceleration torque setting means 1. The control circuit 11 detects the speed of the motor 3 from the tachometer pulse output from the tachometer 5 and controls the speed of the motor 3. The tachometer pulse is used to detect the moving distance of the cell drum 4, and the position of the cell drum 4 is controlled by controlling the rotation of the motor 3.

Numeral 15 is a cell position slit,
The photo sensor 16 causes the cell drum 4 to access the accessor 36.
It is for determining whether or not is accessible.

FIG. 5 shows a hardware configuration diagram of the control circuit 11. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals. The rotation control means 2 includes a central processing unit (CPU) 21,
It is composed of a D / A converter 22, an amplifier 23, a switching circuit 24, and a power amplifier 25. CPU2
1 outputs digital data corresponding to the current supplied from the power amplifier 25 to the motor 3. The D / A converter 22 converts the digital data output by the CPU 21 into an analog signal. The amplifier 23 is the D / A converter 2
The output signal of 2 is amplified and output.

The switching circuit 24 is a power amplifier 25.
In order to reduce the power consumption of the power amplifier 25, the power amplifier 25 is switched according to the output signal of the amplifier 23. The power amplifier 25 is switched by the switching circuit 24 and supplies a current corresponding to the digital data output from the CPU 21 to the motor 3.

The tachometer 5 which is a tachometer is 90 °
Two-phase tachometers with different phases output 500 pulses per revolution of the motor 3, respectively. The two-phase tachometer 5 can detect the rotation direction of the motor 3.
Reference numeral 27 is a tachometer pulse measurement timer, which measures the period of the tachometer pulse output by the tachometer 5. Reference numeral 26 denotes a tachometer pulse counter, which generates a quarter tacho pulse (hereinafter referred to as QTP) having a quarter period from the tachometer pulse output from the tachometer 5 and counts this QTP.

The method of controlling the cell drum 4 in this embodiment will be described below. The cell drum 4 is driven by the motor 3 via a gear 17 of about 150: 1. When the cell drum 4 is moved to perform position control, the CPU 2
1 sets the remaining QTP number in the tacho pulse counter 26 according to the moving distance of the cell drum 4, and sets the remaining QTP.
The motor 3 is driven so that the number becomes 0 by subtraction by QTP.

To control the speed of the motor 3, the CPU 21 measures the rotation speed of the motor 3 from the cycle of the tacho pulse measured by the tacho pulse cycle measurement timer 27, and outputs the motor current data so that the predetermined rotation speed is reached. , By adjusting the current of the motor 3.

FIG. 6 shows how the motor 3 is controlled. FIG. 3A shows the rotation speed of the motor 3 with respect to time when the cell drum 4 is moved to perform position control. Further, FIG. 3B shows the current of the motor 3 at this time. As shown in the figure, when the cell drum 4 is accelerated from a stationary state to a steady speed, a predetermined current corresponding to the inertia moment J and friction is applied to the motor 3 until the rotation speed of the motor 3 reaches a predetermined value. The sink accelerates. next,
After the rotation speed of the motor 3 reaches a predetermined value, a current according to friction is passed.

When the motor 3 is decelerated to stop the cell drum 4 at a predetermined position, a predetermined deceleration current I corresponding to the moment of inertia J corresponding to the weight of the cell drum and friction.
_{Stream D0} . In the conventional library device, the deceleration current I _D0 is set to a constant value for deceleration. If the calculated moment of inertia is accurate, deceleration is performed at a predetermined reference speed as indicated by the solid line in FIG. _6A even if the deceleration current I _D0 is set to a constant value.

FIG. 7 shows a reduction executed by the CPU 21 of this embodiment.
The flowchart of a speed routine is shown. Place the cell drum 4
This deceleration control of the motor 3 when stopped at a fixed position
The deceleration routine is performed. The deceleration routine is explained below
To do. In the deceleration routine, when deceleration is planned as shown in FIG.
Interval t_s(500 ms) equally divided into fixed time intervals (this implementation
In the example, the rotation speed of the motor 3 is divided into 50 equal parts (50 ms).
After measurement, the rotation speed of the motor 3 is measured at each measurement time t._k(This
In the example of FIG. _rkMatches
So that the deceleration current of the motor 3 is adjusted.

In the figure, deceleration torque setting means 1
Is step 101. Further, the speed error calculating means 6
, Step 104, Step 105, and Step 1
It consists of 06. Further, the correction torque calculation means 7 is step 107.

When the position of the cell drum 4 is controlled by moving the cell drum 4, the cell drum 4 set in the tacho pulse counter 26 is set.
When the residual QTP number according to the moving distance of reaches a predetermined value, for example, 5000 by subtraction by QTP, the deceleration routine is started and the deceleration of the motor 3 is started.

First, at step 101, the deceleration current I _D0 corresponding to the inertia moment J and friction at the start is calculated. Next, in step 102, the rotation means control unit 2
A deceleration current I _{D0 is} passed through the motor 3. In step 103,
It is determined whether the motor 3 has started reverse rotation after the speed becomes zero. When the motor 3 has started reverse rotation, this routine is ended, and when reverse rotation has not started, the routine proceeds to step 104.

In the speed error calculating means 6 consisting of steps 104, 105 and 106, the period of the tachometer pulse is measured, and the reference speed v _rk at each measurement time t _k of the deceleration scheduled time t _s and the actual motor are measured. corresponding to the speed error between the third rotational speed, it calculates the period error between the period n _k of the reference period n _rk and tachometer pulses in each measurement time t _k.

In step 104, since the period of the tachometer pulse is measured at a constant time interval, the deceleration scheduled time t
A time interval of 50 ms is created by dividing _s into 10 equal parts. Next, in step 105, the tacho pulse period measurement timer 2
7 was measured, read the cycle n _k tachometer pulse at time t _k (in this example, k is an integer of from 1 to 10). Next, in step 106, the period _{t k of the} tachometer pulse read in step 105 and the reference period n _rk
And the absolute value of the difference n _rk −n _k is compared with the periodic error S
Calculated as VERR, and the sign of n _rk −n _k is SV
Calculate as SGN.

Next, the correction torque calculating means 7 in step 107 calculates the deceleration correction current I _D1 according to the cycle error SVERR calculated in steps 104 to 106. This results in calculating the value of the deceleration correction current I _D1 corresponding to the speed error from the reference speed.

The inventor of the present invention assigns the symbol SVSGN to SVERR.J (J is the moment of inertia) for the optimum value of the deceleration correction current for making the rotation speed of the motor 3 during deceleration close to the reference speed. Since it is confirmed that the value is a value, the present invention utilizes this fact. Step 1
In 07, the cycle error SVER calculated in step 106
From R, the absolute value of the deceleration correction current I _D1 is obtained as SVERRJ, and the deceleration correction current I _D1 is calculated by adding the sign SVSGN to this value.

[0037] When the rotational speed of the motor 3 is less than the reference speed, at _{n rk -n k <0, I} D1 is a negative value, the correction of increasing the rotational speed. Further, when the rotational speed of higher than the reference speed motor 3, with n _rk -n _k> 0, I
_D1 has a positive value, which is a correction to reduce the rotation speed.

Next, at step 108, the rotating means control section 2 causes the corrected current of I _D0 + I _D1 to flow through the motor 3. Since the deceleration current is corrected to I _D0 + I _D1 , the motor 3
The rotation speed of is corrected so as to approach the reference speed v _rk at time t _k .

Next, at step 109, it is judged whether or not the rotation direction is reversed after the motor 3 has reached the speed of 0. If the rotation direction is reversed after the motor 3 has reached zero speed, this routine ends. Motor 3
If the rotation direction of is not reversed, step 110
Proceed to. Next, in step 110, it is judged whether or not the period n _{k of the} tachometer pulse has been measured a prescribed number of times (10 times in this example). If the measurement has not been performed the specified number of times, the process proceeds to step 103 to perform the next measurement. When the measurement of the specified number of times is completed, this routine is ended.

The dashed-dotted line in FIG. 6A showing the deceleration state during deceleration is smaller than the value obtained by calculating the actual moment of inertia J when the deceleration current during deceleration is not corrected. As a result, the case where the speed during deceleration becomes smaller than the reference speed is shown. In this case, the cell drum 4 stops before the predetermined position, and the position must be corrected thereafter. Therefore, it takes an extra time to stop the cell drum 4 at a predetermined position, and vibration may occur in the cell drum 4 around the target position.

Even when the rotation speed of the motor 3 deviates from the reference speed in this way, in the deceleration routine of this embodiment, the difference between the deceleration current and the reference speed is indicated by the line I _D0 + I _{D1 in} FIG. 6B. As shown by the solid line in FIG. 6A, deceleration can be performed at a predetermined reference speed. For this reason,
It is possible to prevent the cell drum 4 from stopping before reaching a predetermined position or overshooting, and it does not take extra time to stop the cell drum 4 at a predetermined position, and the cell drum 4 vibrates around the target position. Does not occur.

As described above, according to this embodiment, the deceleration current of the motor 3 is corrected so that the rotation speed of the motor 3 matches the reference speed during deceleration, so that the inertia moment J of the cell drum 4 can be accurately determined. When it is not present, the time to reach the target position can be shortened, and vibration of the cell drum 4 around the target position can be prevented.

The deceleration scheduled time t _s of the deceleration routine,
The time interval for measuring the speed of the motor 3 and the number of times the speed is measured are not limited to the values in this embodiment, and may be appropriate values according to the embodiment.

In this embodiment, the speed is not directly calculated,
Although the correction current corresponding to the difference from the reference speed is indirectly obtained from the cycle of the tachometer pulse, it is also possible to directly obtain the speed and obtain the correction current corresponding to the difference from the reference speed.

[0045]

As described above, according to the present invention, when decelerating, the torque of the rotating means is corrected so that the rotating speed of the rotating means coincides with the reference speed, so that the moment of inertia of the cell drum cannot be accurately known. The time required to reach the target position can be shortened, and the cell drum can be prevented from vibrating around the target position.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is an external view of an embodiment of the present invention.

FIG. 3 is a sectional view of an embodiment of the present invention.

FIG. 4 is an explanatory diagram of an embodiment of the present invention.

FIG. 5 is a hardware configuration diagram of a control circuit.

FIG. 6 is a diagram showing how the motor is controlled.

FIG. 7 is a flowchart of a deceleration routine.

[Explanation of symbols]

 1 deceleration torque setting means 2 rotating means control section 3 rotating means 4 cell drum 5 tachometer 6 speed error calculating means 7 correction torque calculating means 11 control circuit 13 slit 14 cartridge 15 slit 16 photo sensor 17 gear 21 central processing unit (CPU) ) 22 D / A converter 23 Amplifier 24 Switching circuit 25 Power amplifier 26 Tacho pulse counter 27 Tacho pulse period measurement timer 31 Cartridge loading section 32 Cartridge ejection section 33 Operation panel 34 Cartridge direct insertion and ejection operation panel 35 Cartridge direct insertion and ejection door 36 Accessor 37 magnetic tape drive device 38 robot control unit 39 control device

Claims (4)

[Claims] 1. A rotating means control section (2) controls a rotating means (3) according to a value of the decelerating torque set by the decelerating torque setting means (1), and the rotating means (3) controls the cell drum ( In a library device for rotating 4), a rotating speed meter (5) for generating a signal corresponding to the rotating speed of the rotating means (3) and an output signal of the rotating speed meter (5) are used to rotate the rotating means (3). Speed error calculating means (6) for calculating the difference between the reference speed and the rotation speed of the rotating means (3) at the time of deceleration, and the value of the torque to be corrected from the output data of the speed error calculating means (6). A library device, comprising: a correction torque calculating means (7) for calculating and inputting the value of the torque to be corrected to the rotating means control section (2). 2. The library apparatus according to claim 1, wherein the rotating means (3) is a motor. 3. The tachometer (5) outputs a signal in which the number of pulses per unit time changes according to the rotational speed of the rotating means (3). The described library device. 4. The speed error calculating means (6), based on the output signal of the tachometer (5), the reference speed at the time of deceleration of the rotating means (3) and the rotating speed of the rotating means (3). 4. The library device according to claim 1, wherein the difference between the two is calculated at a predetermined time interval.