JPH11250532A - Information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of the device, which runs at a slow speed, without increasing the cost of the device by precisely detecting the time intervals from a rise to a fall of each pulse output, from the fall to a rise, from the rise to a rise and from the fall to a fall and controlling the speed and the position of a running medium. SOLUTION: An information medium 1 is moved by feeding and taking-up reels 2 and 4 and driving motors 5 and 6 and passes an information recording and reproducing head 3. The motor current instructing values, which control the speed and the tension of the medium 1 to target values, are outputted to DA converters 17 and 18 from an output port 22. A computing element 21 transmits the control parameter, which is computed by using the combination of the measured values of the sate quantities outputted from an input port 23 and the mechanism characteristic constants stored in a ROM 25 to a RAM 24, and updates control variables and constants. The reel angular speeds are computed by storing the pulse inputs from encoders 7 and 8 in the counters of the element 21 through the port 23, computing the differences of the counter values between pulses and measuring the time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic tape device,
The present invention relates to an information recording / reproducing apparatus using a web-shaped information medium such as an optical tape and a magneto-optical tape, and particularly, to a small-sized information recording / reproducing apparatus using a small encoder having a low resolution, a high-resolution, high-precision speed and position. This is an information recording / reproducing apparatus that is most suitable for performing detection.

[0002]

2. Description of the Related Art An information recording / reproducing apparatus for recording / reproducing a signal on / from a tape has been used as a backup apparatus for a magnetic disk for computer data recording, which has been very large in recent years.

[0003] In the computer market, downsizing is rapidly progressing, and there is a demand for an information recording / reproducing apparatus to have a smaller size and a lower price with an increase in storage capacity.

[0004] One of the small magnetic tape devices is 8 mm.
There is a magnetic tape device that performs helical recording using a tape.

In order to reduce the size of the apparatus, it is necessary to reduce the number of parts and the size of the parts. One of the measures is to employ an ultra-thin reel motor.

Further, a magnetic tape device for performing helical recording has an extremely low tape speed and requires a high-resolution encoder.

However, when an ultra-small and thin reel motor is used, the encoder for detecting the speed needs to be small. Therefore, the number of magnetizations for pulse detection is limited, and it is very difficult to realize a high-resolution encoder.

In the case of using an arithmetic unit such as a general-purpose microprocessor, the number of input ports is limited, so that it is difficult to handle a plurality of pulse output units separately.

[0009]

As a countermeasure against this, the detection output is made to have a resolution of 8 times by using a decomposition circuit, and the drive waveform data of the motor corresponding to the 8 times resolution is stored in a ROM in advance, and the ROM is used to store the data. Japanese Patent Application Laid-Open No. 5-260789 discloses a means for correcting the phase of a drive waveform to be read out using an arbitrary correction value supplied to a correction value input terminal.

However, the method of increasing the resolution by performing multiplication using pulse outputs of a plurality of phases generally has a problem that the accuracy of the phase difference of each phase is coarse and the detection accuracy is reduced.
As a countermeasure for this, there is a method of suppressing a sensor mounting error by assembling adjustment, but it requires a great deal of manpower and time, and causes an increase in cost.

Further, since the correction means requires a large-capacity ROM or memory for storing a large amount of waveform data, it is not suitable for a device aiming at miniaturization and cost reduction of the device. An optimum correction value obtained by measuring characteristics or a correction value theoretically obtained by calculation is required.

[0012]

In order to solve the above-mentioned problems, an information recording / reproducing apparatus according to the present invention employs a high-resolution pulse group from the rising edge to the falling edge of each highly accurate pulse output. Alternatively, there is provided control means for detecting the time from falling to rising, from rising to rising, from falling to falling, and controlling the traveling speed and position of the information medium.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail. FIG. 1 is a block diagram of an embodiment of the present invention, and FIG.
FIG. 3 is a conceptual diagram of a pulse multiplied by using a plurality of pulse groups, and FIG. 3 is an operation flowchart of the embodiment of the present invention.

In FIG. 1, an information medium 1 is fed out from a supply reel 2 and wound up on a take-up reel 4 via an information recording / reproducing head 3 and a tension sensor 9. Supply reel 2
Is the drive motor 5, and the take-up reel 4 is the drive motor 6.
The information medium 1 from the supply reel 2 to the take-up reel 4
The information recording / reproducing head 3 is driven to perform phase shifting at a predetermined speed from the take-up reel 4 to the supply reel 2, and the information recording / reproducing head 3 records or reproduces signals on the information medium 1. The drive motor 5 is provided with an encoder 7 which detects the rotation amount of the supply reel 2 directly connected to the drive motor 5 and generates a number of pulses proportional to the rotation amount of the supply reel 2. Similarly, the drive motor 6 is provided with an encoder 8 which is directly connected to the take-up reel 4.
And outputs a number of output pulses proportional to the rotation amount of the take-up reel 4. The number of pulses is proportional to the angular speed of the reel, so if you measure the time between pulses,
Information medium 1 at the position of supply reel 2 and take-up reel 4
The speed can be calculated by using the angular velocity and the radius information.

The drive motors 5 and 6 are driven by drive currents output from power amplifiers 15 and 16 each comprising a constant current amplifier. On the other hand, the inputs of the power amplifiers 15 and 16 are the outputs of the DA converters 17 and 18. DA converter 1
7 and 18 are output ports 2 of the digital controller 20.
2. The motor current command value output from 2 is input, converted into an analog signal, and output.

The input port 23 receives the pulses generated by the encoders 7 and 8 and sends them to the computing unit 21.

The input port 23 is connected to the tension sensor 9.
Is sent to the arithmetic unit 21 via the AD converter 10.

The arithmetic unit 21 is a digital controller 20
It has a function to control the whole.

That is, by driving the drive motors 5 and 6,
A motor current command value for controlling the speed and the tension of the information medium 1 when the supply reel 2 and the take-up reel 4 are rotated to pass the information recording / reproducing head 3 to predetermined target values is determined and output. From the port 22 to the DA converter 17,
18 is output.

The arithmetic unit 21 inputs control variables and constants necessary for determining the motor current command value to the input port 2.
The calculation is performed using a combination of several state quantity measurement values sent from the control unit 3 and a mechanism characteristic constant stored in a ROM (Read Only Memory) 25 in advance. Then, each output control parameter is stored in a RAM (Random Access Mem) at an appropriate time.
ory) 24 to update the control variables and constants.

The following method is generally used to calculate the reel angular velocity. The arithmetic unit 21 has an oscillator (not shown) serving as a reference and a counter (not shown) that increases with the oscillation cycle. The counter value when the pulse input from the encoder is generated is stored, the time between the counters is measured from the difference between the counter values between the pulses, and the reel angular velocity is calculated from the calculated time.

FIG. 2 is a conceptual diagram of the output pulse of the encoder 8 in FIG.

For example, in FIG.
It outputs four-phase output pulses B, C, and D. A circuit (not shown) first generates an EOR output of the A and B phases and an EOR output of the C and D phases, and further generates EOR of these two generated outputs.
An OR output is generated and multiplied by 8. A, B, C, D phase 1
If the phase difference when the cycle is 360 ° is 45 °, which is the ideal value, the pulse multiplied by 8 is output at 45 ° intervals.

However, the accuracy of the actual phase difference is limited, and generally an error of about 10% occurs. This is very large compared to the accuracy of one phase, for example, phase A, from the rise to the next rise or from the rise to the fall, which is generally about several percent.

The present invention is a means for executing travel control and position control of an information medium by using this fine output.

FIG. 3 is an operation flowchart of the embodiment of the present invention. FIG. 3 is a flowchart for a case where an n-phase output pulse is used, where n = 4, and a description will be given in conjunction with FIG.

First, the process of step F10 is performed. In step F10, preprocessing of data for detecting time in step F60 is executed. That is, by using a counter value e0 to be described later, the counter value before one process is changed to e1,.
The counter value before the processing is set to e4.

In step F20, it is determined whether or not pulse detection has been performed, and if pulse detection has been performed, step F30 is executed.

In step F30, the counter value at the time of pulse detection is stored in e0.

In step F40, einit used in step F50 is incremented.

In step F50, it is determined whether or not to calculate the time between pulses. That is, when n = 4, it is determined whether or not the pulse detection before four processes has been executed. If the pulse detection before the 4th processing has been executed, the step 60 is executed, and if not, the operation is not executed and the operation ends.

In step F60, the period T between each pulse
Ask for. The running speed and the phase are controlled using this T. In one example, v = 2πr / DT (r: reel radius,
(v: target speed, D: resolution).

If this technique is applied, it is possible to perform high-precision running control even with a small motor having a small encoder, and perform 3.5-inch form factor size helical recording using an 8 mm tape. It is possible to realize a magnetic tape device.

In particular, when an arithmetic unit such as a general-purpose microprocessor having a limited number of input ports is used, a plurality of pulse output means can be distinguished and handled with a limited number of input ports, which is very useful. It is.

In the above embodiment, the time from the rise to the fall of the pulse output is used. However, the time from the fall to the rise can be used.

Next, another embodiment of the present invention will be described.
This embodiment uses the time from the rise of the pulse output to the rise in the first embodiment.

FIG. 1 is common and will not be described.

FIG. 4 is a conceptual diagram of an output pulse in this embodiment. The difference from FIG. 2 is that the time from the rise of the pulse output to the rise is detected, and the other points are common. If n = 8 in FIG. 3, this is the same as in the first embodiment.

In the second embodiment, the time from the rise of the pulse output to the rise is used. However, the time from the fall to the fall can be used.

Although the first and second embodiments are applied to an information recording / reproducing apparatus as an example, it is needless to say that the same correction can be performed for an encoder alone. Therefore, the present invention can be applied to all devices using an encoder.

In the first and second embodiments, the encoder uses a pulse multiplied by 8 using a 4-phase pulse. However, it is needless to say that the present invention can be applied to a case where another pulse multiplied by N is used. It is possible.

[0042]

According to the present invention, from the rising to the falling of each highly accurate pulse output, or from the falling to the rising,
Since the speed control is performed using the time from the rise to the rise and from the fall to the fall, it is possible to realize a small-sized, low-speed traveling information recording / reproducing apparatus without significant cost increase.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of output pulses of the encoder of the embodiment of FIG.

FIG. 3 is an operation flowchart of the embodiment of FIG. 1;

FIG. 4 is another conceptual diagram of an output pulse of the encoder of the embodiment of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Information medium, 2 ... Supply reel, 3 ... Information recording / reproducing head, 4 ... Take-up reel, 5, 6 ... Drive motor, 7, 8 ...
Encoder, 9 tension sensor, 10 AD converter,
15, 16: power amplifier, 17, 18: DA converter, 20: digital controller, 21: arithmetic unit, 2
2 ... output port, 23 ... input port, 24 ... random
Access memory (RAM), 25 ... read-only memory (ROM).

Claims (8)

[Claims] 1. A web-like information medium travels on said recording / reproducing head using a recording / reproducing head for recording / reproducing a signal, thereby recording / reproducing information on / from said information medium, and a traveling speed and a position of said information medium. In the information recording / reproducing apparatus having an encoder that generates a pulse proportional to the rotation angle of the motor for the control, the resolution is improved in the rotation angle detection means by performing multiplication using a plurality of pulse output means. From the rising to the falling of each pulse output means from the pulse group generating means and the pulse group,
Alternatively, using a pulse time detection means and the pulse time detection means to detect the time from the fall to the rise,
An information recording / reproducing apparatus comprising a control unit for controlling a traveling speed and a position of the information medium. 2. A recording / reproducing head for recording / reproducing a signal, wherein a web-shaped information medium travels on the recording / reproducing head to record / reproduce information on / from the information medium, and a traveling speed and a position of the information medium. In the information recording / reproducing apparatus having an encoder for generating a pulse proportional to the rotation angle of the motor for controlling the rotation, the resolution is improved in the rotation angle detecting means by performing multiplication using three or more pulse output means. From the pulse group generating means and the pulse group from the rise to the fall of each pulse output means, or, using the pulse time detection means and the pulse time detection means to detect the time from the fall to the rise, An information recording / reproducing apparatus comprising control means for controlling a traveling speed and a position of an information medium. 3. A recording / reproducing head for recording / reproducing a signal, wherein a web-shaped information medium travels on the recording / reproducing head to record / reproduce information on / from the information medium, and a traveling speed and a position of the information medium. In the information recording / reproducing apparatus having an encoder that generates a pulse proportional to the rotation angle of the motor for the control, the resolution is improved in the rotation angle detection means by performing multiplication using a plurality of pulse output means. From the pulse group generating means and the pulse group from the rise to the rise of each of the pulse output means, or, using the pulse time detection means and the pulse time detection means to detect the time from the fall to the fall,
An information recording / reproducing apparatus comprising a control unit for controlling a traveling speed and a position of the information medium. 4. A recording / reproducing head for recording / reproducing a signal, wherein a web-shaped information medium travels on the recording / reproducing head to record / reproduce information on / from the information medium, and a traveling speed and a position of the information medium. In the information recording / reproducing apparatus having an encoder for generating a pulse proportional to the rotation angle of the motor for controlling the rotation, the resolution is improved in the rotation angle detecting means by performing multiplication using three or more pulse output means. From the pulse group generating means and the pulse group from the rise to the rise of each pulse output means from the pulse group,
Alternatively, information recording characterized by comprising pulse time detecting means for detecting the time from falling to falling and control means for controlling the traveling speed and position of the information medium using the pulse time detecting means. Playback device. 5. An encoder for generating a pulse proportional to the rotation angle of a motor, wherein a plurality of pulse output means are used to perform multiplication, whereby the rotation angle detection means has a high resolution pulse group generation means. From the pulse group from the rise to the fall of each of the pulse output means, or, using the pulse time detection means and the pulse time detection means to detect the time from the fall to the rise, the traveling speed and position of the information medium An encoder comprising control means for performing control. 6. An encoder for generating a pulse proportional to the rotation angle of a motor, by performing multiplication by using three or more pulse output means, thereby generating a pulse group whose resolution is improved by said rotation angle detection means. From the pulse group to the pulse output means from the rise and fall, or from the pulse group, using the pulse time detection means and the pulse time detection means to detect the time from the fall to the rise, the travel speed of the information medium and An encoder comprising control means for controlling a position. 7. An encoder for generating a pulse proportional to the rotation angle of a motor, wherein a plurality of pulse output means are used to perform multiplication, whereby the rotation angle detection means is provided with a pulse group generation means having a high resolution. From the pulse group from the rise to the rise of each pulse output means, or, using the pulse time detection means and the pulse time detection means to detect the time from the fall to the fall, the traveling speed and position of the information medium An encoder comprising control means for performing control. 8. An encoder for generating a pulse proportional to the rotation angle of a motor, wherein the multiplication is performed by using three or more pulse output means, so that the rotation angle detection means generates a pulse group with high resolution. From the pulse group to the rise of the pulse output means from the pulse group, or, using the pulse time detection means and the pulse time detection means to detect the time from the fall to the fall, the traveling speed of the information medium and An encoder comprising control means for controlling a position.