JPH10112993A - Motor control equipment and information recording and reproducing equipment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable detecting speed and position with high resolution and high precision, in a small-sized information recording and reproducing equipment wherein a small-sized encoder of low resolution and web form information medium are used. SOLUTION: Data are recorded or reproduced from a information medium 1 by traveling it on a write and read head 3. Encoders 7, 8 generate a plurality of pulses which are in proportion to the rotation angles of motors 5, 6 for controlling the traveling speed and the position of the information medium. In this case, multiplication is performed (26) by using pulses of a plurality of phases, and a pulse group of high resolution is generated. The periods between pulses of the pulse group are detected. The ratio of the detected period to a specific period is previously calculated. The period ratio is operated and corrected to each of the periods of the pulse group which are detected during operation, and highly precise periods are calculated. By using the calculated periods, the traveling speed and the position of the motor are controlled.

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 speed detection also needs to be small, and therefore the number of magnetizations for pulse detection is limited, and a high-resolution encoder is used. It is very difficult to achieve.

[0008]

As a countermeasure against this, a detection output is obtained with a resolution of eight times using a decomposing circuit.
Japanese Patent Laid-Open Publication No. Hei 5 (1993) -1993 discloses a method in which driving waveform data of a motor corresponding to a double resolution is stored in a ROM in advance, and the phase of the driving waveform read from the ROM is corrected by an arbitrary correction value supplied to a correction value input terminal. No. 260789.

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 aimed 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.

[0011]

In order to solve the above-mentioned problem, in an information recording / reproducing apparatus according to the present invention, speed control is performed using a high-precision pulse, and a phase difference between a pulse group having a high resolution at that time is determined. It is provided with a phase difference correcting means capable of accurately detecting the speed even if there is a variation in the phase difference of the pulse group by measuring and learning at least once.

With the above configuration, the present invention can provide the following functions.

[0013] Speed control is performed using a highly accurate pulse,
By measuring and learning the phase difference of the pulse group with high resolution at that time, the variation of the phase difference of the pulse group is corrected, thereby realizing a small-sized, low-speed traveling information recording / reproducing apparatus without significant cost increase. can do.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail. FIG. 1 is a block diagram of one embodiment of the present invention,
2 is a conceptual diagram of a pulse multiplied by using a plurality of pulse groups, FIG. 3 is an operation flow diagram of initial learning according to the embodiment of the present invention, and FIG. 4 is an operation flow diagram of phase difference correction according to the embodiment of the present invention. is there.

Here, 1 is an information medium, 2 is a supply reel, 3 is an information recording / reproducing head, 4 is a take-up reel,
5 and 6 are drive motors, 7 and 8 are encoders, 9 is a tension sensor, 10 is an AD converter, 15 and 16 are power amplifiers, 17 and 18 are DA converters, 20 is a digital controller, 21 is a calculator, and 22 is an output. Port, 23 is an input port, 24 is a random access memory (RA
M), 25 are read only memories (ROM), 2
Reference numeral 6 denotes a multiplier circuit.

In FIG. 1, an information medium 1 is unreeled from a supply reel 2 and wound 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 transfer a signal to or from the take-up reel 4 to the supply reel 2 at a predetermined speed.

The drive motor 5 is provided with an encoder 7 which is directly connected to the drive motor 5.
And the number of pulses generated is proportional to the amount of rotation of the supply reel 2. Similarly, an encoder 8 is attached to the drive motor 6, which detects the rotation amount of the take-up reel 4 directly connected to the drive motor 6, and outputs a number of output pulses proportional to the rotation amount of the take-up reel 4. I do. As an example of the encoder, an encoder composed of a permanent magnet and a magnetic sensor, an encoder composed of a slit and an optical sensor, and the like are cited. The N pole and the S pole of the magnet are alternately arranged to face the magnetic sensor. With such a structure, several hundred pulses can be detected for one rotation.

Since the number of pulses from the encoder within these fixed time intervals is directly proportional to the angular speed of the reel, the speed of the information medium 1 at the positions of the supply reel 2 and the take-up reel 4 can be calculated.

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 outputs the output of the tension sensor 9 to the AD converter 1.
It is sent to the arithmetic unit 21 via 0.

The arithmetic unit 21 is a digital controller 20
It has a function to control the whole. That is,
To drive the drive motors 5 and 6 to rotate the supply reel 2 and the take-up reel 4 to control the speed and tension of the information medium 1 when passing through the information recording / reproducing head 3 to predetermined target values, respectively. And outputs the motor current command value to the DA converters 17 and 18 from the output port 22.

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.

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

The encoder 8 includes, for example, A, B, C,
A four-phase D output pulse is output. One cycle (360 degrees) in A of FIG. 2 indicates a cycle corresponding to a unit set out of several hundred combinations of N poles and S poles in the example of the magnetic sensor. As an example, in order to obtain four-phase output pulses, the positions of each magnetic sensor are shifted and four are arranged.

First, the A and B phase EOs are
An R output and an EOR output of C and D phases are generated, and an EOR output of these two generated outputs is generated and quadrupled.
If the phase difference between the A, B, C, and D phases is 360 ° when the cycle is 360 °, the quadrupled pulse is output at 90 ° intervals. Also, the quadrupled pulse can be obtained by software according to a program by detecting the rising timing of each phase without using the multiplying circuit.

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

The present invention is a means for correcting a coarsely-multiplied output using the fine output.

FIG. 3 is an operation flowchart of the initial learning according to the embodiment of the present invention, which is executed by the controller 20. In FIG. 2, a pulse generated from the rising edge of the A-phase among the quadrupled pulses is denoted by e0, and e1 is hereinafter referred to as e1,
... E4. Here, e4 is generated from the rising edge of the A phase similar to e0.

First, the process of step F10 is performed.
In step F10, for example, the tape is run at a constant speed at which the tape can run stably using only the A-phase rising edge.

In step F20, it is determined whether or not detection of e0 has been performed.
Execute 0.

From step F30 to step F80, the following calculation is executed for the detection from e1 to e4.

In step F40, it is determined whether or not ei is detected. If ei is detected, step F50 is executed.
Execute

In step F50, the period T between each pulse
Find i. This period coincides with the ideal period T0 = 2πr / Dv if the vehicle is traveling at a constant speed. (R: reel radius, v: target speed, D: resolution) In step F60, the detection cycle Ti and the ideal cycle T0
ΔTi is calculated. (ΔTi = Ti / T0) This δTi is 1 in an ideal state, and is used to correct the encoder phase difference.

In step F70, the next generated pulse is selected, and in step F80, it is determined whether or not δT4 has been detected.

FIG. 4 is a flowchart showing the operation of correcting the phase difference according to the embodiment of the present invention.

First, the process of step F110 is performed.
In step F110, it is determined whether or not ei has been detected. If ei has been detected, step F120 is executed.

In step F120, the period Ti between each pulse is determined. As described above with reference to FIG. 3, this period coincides with the ideal period T0 if the vehicle is traveling at a constant speed.

In step F130, step F120
The correction value Ti ′ is obtained from the cycle Ti calculated in the above and the correction coefficient δTi.
Is corrected by Ti ′ = f (Ti, δTi). In one example, the correction of Ti ′ = Ti / δTi is executed, and the running speed and the position (which can be obtained as an integral value of the running speed) are controlled using this Ti ′. (V = 2πr / D
Ti) If this technology is applied, it is possible to perform high-precision traveling control even with a small motor having a small encoder, and to perform 3.5-inch form factor size helical recording using 8 mm tape. It is possible to realize a tape device.

In the above embodiment, the present invention is applied to an information recording / reproducing apparatus as an example, but it is needless to say that the same correction can be performed for the encoder alone. Therefore, it can be applied to all devices that use the encoder.

Also, in the above embodiment, the encoder is
Although a phase pulse is used and a pulse multiplied by 4 is used, it is needless to say that the present invention can be applied to a case where another pulse multiplied by N is used. As an example, it is also possible to use a pulse multiplied by 8 using a falling pulse, as shown in the lower part of FIG.

[0041]

According to the present invention, speed control is performed using a high-precision pulse, and the phase difference of the group of pulses with high resolution at that time is measured and learned to correct the variation in the phase difference of the group of pulses. In addition, a low-speed traveling information recording / reproducing apparatus can be realized without a significant increase in cost.

[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 and an operation flow chart of a pulse multiplied by using a plurality of pulse groups in the embodiment of FIG. 1;

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

FIG. 4 is an operation flowchart of the phase difference correction of the embodiment of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 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 22 output port 23 Input port 24 Random access memory (RAM) 25 Read-only memory (ROM) 26 Multiplier circuit

Claims (5)

[Claims] 1. A motor control device having an encoder that generates pulses of a plurality of phases in proportion to the rotation angle of a motor, wherein a pulse group that has been improved in resolution by performing multiplication using pulses of the plurality of phases is provided. Generate and pre-learn the phase difference of each pulse in the high resolution pulse group, apply the learning to each pulse of the pulse group detected during operation, and use each of the learned pulses A motor control device for controlling the traveling speed and position of a motor using a motor. 2. An information medium is recorded on and reproduced from the information medium by running the information medium on a recording / reproducing head, and a plurality of information mediums are controlled in proportion to a rotation angle of a motor for controlling a traveling speed and a position of the information medium. In an information recording / reproducing apparatus having an encoder that generates a phase pulse, a pulse group having a high resolution is generated by performing multiplication using a pulse of a plurality of phases, and each pulse in the pulse group having a high resolution is generated. Learning in advance, applying the learning to each pulse of a group of pulses detected during operation, and controlling the running speed and position of the motor using each of the learned pulses. Characteristic information recording / reproducing device. 3. A motor control device having an encoder that generates pulses of a plurality of phases in proportion to the rotation angle of a motor, wherein a pulse group that has been improved in resolution by performing multiplication using pulses of the plurality of phases is provided. Generate and detect a period between each pulse in the high resolution pulse group, calculate a period ratio of the detection period and a specified period in advance, and calculate the period for each period of the pulse group detected during operation. A motor control device comprising calculating and correcting a ratio to calculate each highly accurate cycle, and controlling the running speed and position of the motor using the calculated cycle. 4. Recording and reproduction of information on the information medium by running the information medium on a recording / reproducing head, and a plurality of the information mediums are controlled in proportion to a rotation angle of a motor for controlling a traveling speed and a position of the information medium. In an information recording / reproducing apparatus having an encoder that generates a phase pulse, a pulse group having a high resolution is generated by performing multiplication using a pulse of a plurality of phases, and each pulse in the pulse group having a high resolution is generated. Between the detected periods and the period ratio between the detected period and the specified period is calculated in advance, and the period ratio is calculated and corrected for each period of the pulse group detected during operation to calculate each period with high accuracy And an information recording / reproducing apparatus for controlling the running speed and the position of the motor using the calculation cycle. 5. The information recording apparatus according to claim 4, wherein the information medium has a web shape, a width of 8 mm, and a dimension of the information recording / reproducing apparatus is 3.5 inch home factor size. Playback device.