JPH0628741A - Servo circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a servo circuit that quickly starts up a motor without causing an over-rotation state. A storage circuit (24) for storing mechanical response information at the time of motor start-up, which is determined by the motor and its load mechanism, and one or a plurality of units for detecting information relating to the response at the motor start-up that changes depending on the situation. And detecting means 21 and 22 of. A start-up speed control data forming means for forming start-up speed control data for starting the motor up to the target rotation speed is provided from the information from the detection means 21 and 22 and the information from the storage circuit 24.
From the time of starting the motor until reaching the target rotation speed,
The motor drive signal is controlled by the start-up speed control data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo circuit for controlling the speed and / or phase of a motor such as a drum motor, a reel motor and a capster motor of a VTR.

[0002]

2. Description of the Related Art For example, a VTR drum motor is speed-servoed so as to rotate at a target rotation speed, for example, a rotation speed of 30 rotations / second, and is rotated in synchronization with a vertical cycle of a video signal. Phase servo is applied.

The speed servo is performed as follows. That is, a frequency generator is provided coaxially with the rotating shaft of the drum motor, and the angular velocity of the drum motor is obtained from the frequency signal FG of the frequency corresponding to the rotating speed of the drum motor from this frequency generator. Angular velocity of the obtained drum motor,
The target rotation speed (angular speed) is compared to obtain an angular speed error as the angular speed error, and the drive signal supplied to the drum motor is controlled so that this error becomes zero.

Further, the phase servo is performed as follows. That is, the drum motor is provided with a pulse generator that generates the pulse PG once per rotation at the specific rotation angle position.

The phase error is obtained by comparing the phase of the pulse PG from this pulse generator with the vertical synchronizing pulse of the video signal or the reference pulse of 30 Hz. Then, the drive signal supplied to the drum motor is controlled so that the phase error becomes a predetermined value.

Generally, both the speed servo and the phase servo are applied to the drum motor, and the drive signal supplied to the drum motor is determined based on the angular velocity error and the phase error. Further, when the motor is started or when the speed servo is deviated, the phase servo is generally applied after the rotational speed is stabilized by the speed servo.

By the way, when the motor is started, the frequency signal FG is not generated because the motor is not rotating. Therefore, the speed error obtained from the frequency signal FG cannot be obtained, so that the drive signal of a constant value is supplied to the motor. Then, conventionally, the drive signal having a constant value at the time of starting is maintained during the motor start-up period, and then the angular velocity is calculated from the cycle of the frequency signal FG generated with the rotation of the motor to obtain the angular velocity error. A drive signal based on the error is supplied to the motor so that the motor can reach the target rotation speed.

Further, regarding the phase servo, conventionally, no phase error is obtained at the time of starting. Moreover, since the phase servo is not applied until the speed servo becomes stable, the rotation phase is not considered when the motor is started.

[0009]

As described above, at the time of starting the motor, the constant value at the time of starting is maintained until several frequency signals FG are obtained, and thereafter, the frequency signal F is maintained.
The target rotation speed is raised by the speed error based on G, but at the time of the rise, the cycle of the frequency signal FG is long and the control cycle is long. For this reason, the motor is likely to have an excessive rotation speed, or the motor speed at the excessive rotation speed is excessively suppressed so that the motor cannot be completely started.

Also, before the target rotation speed is reached,
There was a problem that it took a long time.

Further, since there is no conventional method for obtaining a phase error at the time of start-up, the phase servo is designed to lock the reference phase by applying the phase servo after the motor starts up to the target rotation speed. Has a drawback that it takes time to be pulled into the locked state.

In view of the above points, it is an object of the present invention to provide a servo circuit capable of shortening the pull-in time of the speed servo and the pull-in of the phase servo when the motor is started. To do.

[0013]

In order to solve the above-mentioned problems, the servo circuit according to the present invention generates a frequency signal corresponding to the rotation speed of the motor 1 in correspondence with the reference numerals of the embodiments described later. The motor is provided with a generator 2 and a means for obtaining a phase error according to a phase shift from a reference phase, and the speed error according to the difference between the frequency of the frequency signal and the reference frequency and the phase error. A servo circuit that controls a drive signal to be supplied so that the motor rotates at a predetermined target rotation speed according to the reference frequency and the motor rotates in synchronization with the reference phase. And a memory circuit 24 for storing mechanical response information at the time of starting the motor, which is determined by the load mechanism thereof, and the motor 1 that changes depending on the situation. And one or a plurality of detecting means 21 and 22 for detecting information involved in the response at rising,
The start-up speed control data forming means 20 for forming start-up speed control data for starting up the motor up to the target rotation speed based on the information from the detecting means and the information from the storage circuit, and the motor 1. Means 31 for storing the phase error at the time of the previous stop, and phase data determination means 32 for forming a signal for the phase control at the time of starting the motor based on the stored phase error at the time of the previous stop Is provided, and the drive signal of the motor is controlled by the data obtained by adding the signal from the phase data determination means to the start-up speed control data from the time of starting the motor to the vicinity of the target rotation speed. It is characterized by

[0014]

In the present invention having the above-described structure, the speed servo is started up from the mechanical response at the time of starting the motor and the response information according to the situation such as the temperature and the tape load according to the tape winding diameter. Create speed control data. Then, the drive signal of the motor is controlled by the start-up speed control data to start up.

Therefore, the motor starts up to the target rotation speed along a predetermined starting locus.

Regarding the phase servo, the phase error at the time of the previous stop of the motor is stored, and the phase control data at the start-up is created according to the phase error at the time of the previous stop, and this is the speed servo information. To control the motor.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a servo circuit according to the present invention will be described below with reference to the drawings. FIG. 1 illustrates the present invention.
FIG. 2 is a block diagram of an embodiment when applied to a servo circuit for performing speed control and phase control of a VTR capstan motor, and FIG. 2 is a timing chart for explaining the same.

In FIG. 1, the portion above the alternate long and short dash line is the speed and phase servo system 100 in the steady state, and most of its functions can be realized by a microcomputer. In the figure, each function to be executed is shown by a block. Of course, it is also possible to assemble with hardware. Also,
Below the alternate long and short dash line is a start-up control system 20 from the start of the motor 1 to the target speed and phase lock, or the vicinity thereof.
It is 0. The main part of the start-up control system 200, which is the means for forming the start-up control data, can be realized by a microcomputer.

First, the speed and phase servo system 100 will be described. In FIG. 1, reference numeral 1 denotes a capstan motor, and the capstan motor 1 is provided with a frequency generator 2 coaxially with its rotation shaft. From the frequency generator 2, a frequency signal F corresponding to the rotation speed of the motor is generated.
G is obtained.

Steady state velocity and phase servo is performed as follows. Frequency signal F from frequency generator 2
G is delayed by the delay means 3, and the delayed signal is converted into angular velocity data Sa by subtracting it from the frequency signal FG in the subtraction means 4. Next, the subtraction means 5 subtracts the reference angular velocity data SPref from the angular velocity data Sa to obtain an angular velocity error Sb indicating a deviation from the reference angular velocity.

This angular velocity error Sb is multiplied by a coefficient K1 (K1 is a gain, which is a constant) in the coefficient means 6. The error information Sb is integrated by the integrating means 9, and the integrated result is calculated by the coefficient means 10 as a coefficient K2 (K2
Is a gain, which is a constant). Then, the outputs of the coefficient means 6 and the coefficient means 10 are added by the adding means 7 to obtain the speed error Sv of the speed servo system.

On the other hand, in the case of 8 mm VTR, for example, tracking phase error information (so-called ATF error information) obtained by using the tracking pilot signal recorded on the video signal track is input from the input end 11, and this is the subtraction means. 12 and the difference with the phase reference signal PHref is obtained and the phase error Sc is obtained from this. This phase error Sc is calculated by the coefficient K in the coefficient means 13.
It is multiplied by 3. Then, in the adding means 14, the output data of the coefficient means 13 and the result of integrating the output data of the coefficient means 13 in the integrating means 15 are added, and the phase error information Sd as the addition result is obtained. Then, this phase error information Sd is added to the speed error in the adding means 8 provided in the preceding stage of the integrating means 9.

Therefore, the output Se of the adding means 7 is the sum of the speed error Sv and the phase error Sφ. The output Se of the adding means 7 is supplied to one input terminal a of the switch circuit 16. As will be described later, the switch circuit 16 is provided on the input terminal a side in the steady state, and on the input terminal b side when the motor 1 is started and started.
Each can be switched.

Therefore, in the steady state, the output Se of the adding means 7 is supplied to the PWM signal generating means 17 via the switch circuit 16, and the P signal generated from this generating means 17 is generated.
The duty ratio of the WM signal is changed according to the signal Se. The output PWM signal of the PWM signal generating means 17 is supplied to the motor drive circuit 19 via the low-pass filter 18, and the rotation speed and rotation phase of the motor 1 are controlled. In this example, tracking control is performed by the phase control so that the rotary head correctly scans the video signal recording track.

Next, the startup control system 200 will be described. The start-up speed control data forming means 20 includes a mechanical response when the motor 1 starts up, and a response when the motor 1 starts up according to a situation change such as a reel load which changes according to an ambient temperature and a tape winding diameter (hereinafter, referred to as This is referred to as a situation response), and the start-up speed control data UP for drawing up a start-up locus so that the target speed can be raised to the maximum speed without overspeed. To form.

For example, the time required for start-up is calculated from the mechanical response and the situation response, and the start-up speed control data (corresponding to servo error data) within that time is calculated.
Is formed as a function of time. The start-up trajectory is almost determined by the start-up speed control data, and at the same time, the start-up time is also determined.

In order to detect the situation response, in this example, a temperature sensor 21 for measuring the ambient temperature and a tape winding diameter detecting means are provided. The temperature detection output of the temperature sensor 21 is supplied to the start-up speed control data forming means 20 and the tape winding diameter detection information is supplied to the start-up speed control data forming means 20. The tape winding diameter is detected by a frequency generator 22 provided coaxially with the tape reel drive motor, and a tape winding diameter (from the frequency signal from the frequency generator 22 corresponding to the rotation speed of the tape reel drive motor). Tape position detection means 23 for detecting the tape position). Since the rotation speed of the reel motor differs depending on the winding diameter of the tape wound around the reel, the frequency signal from the frequency generator 22 has a frequency corresponding to the rotation speed of the reel drive motor. The tape winding diameter can be detected by detecting the frequency of the frequency signal. In this example, the tape position detecting means 23 determines the tape position near the tape start position, near the tape end, or in the middle, and supplies the tape position detection information to the start-up speed control data forming means 20. To be done.

The condition of mechanical response is given from the memory 24 to the rising speed control data forming means 20.
The memory 24 stores mechanical response information obtained by performing a startup trial of the motor 1 under a predetermined temperature condition and a predetermined tape position condition.

The timer circuit 25 has an input terminal 2
Start pulse ST generated when starting the motor 1 through 6
Is input, and the timer circuit 25 starts time measurement from the time when this activation pulse is generated. The rising speed control data forming means 20 is supplied from the timer circuit 25 with a timing signal TM for forming the servo control data corresponding to the rising locus at a predetermined time obtained from the start-up. The timing signal TM is a signal having a constant frequency that is sufficiently higher than the frequency of the output frequency signal FG of the frequency generator 2 of the motor 1. The rising speed control data forming means 20 uses the timing signal TM.
Servo control data U at start-up with time base as
Form P.

The timer circuit 25 also measures a time slightly longer than the maximum value of the time from startup to startup, and during that time, a switching signal SW for switching the switch circuit 16 to the input terminal b side. It is formed and is supplied to the switch circuit 16.

Then, the servo control data UP from the rising speed control data forming means 20 is supplied to the sample hold means 28 via the adding means 27. On the other hand, the pulse Sp having a shorter cycle (higher frequency) than the frequency signal FG is obtained from the timer circuit 25, and this is supplied to the sample hold means 28 as a sampling pulse. Then, the output signal UPSH of the sample hold means 28 is supplied to the other input terminal b of the switch circuit 16.

Further, the memory 31 stores phase error information (ATF error in this example) when the motor 1 was last stopped. That is, information on how much the motor 1 has stopped at a phase deviating from the reference phase is written in the memory 31. The phase error information from the memory 31 is supplied to the start-up phase data determining means 32, and phase servo information for enabling the phase lock immediately when the start-up of the motor 1 by the data UP is completed. Is formed by the rising phase data determining means 32. Then, the formed phase servo data is supplied to the adding means 27, and the rising speed control data forming means 2
It is added to the data from 0.

In this case, the speed and phase servo system 1
The error information of the adding means 7 of "00" is supplied to the start-up speed control data forming means 20, whereby the start-up immediate control data is corrected. That is, when the frequency signal FG is generated within the start-up time, an actual error relating to the speed error is obtained, so that the start-up control data is corrected.

Next, the startup operation at the time of startup will be described with reference to the timing chart of FIG. When the activation pulse ST (FIG. 2A) is input through the input terminal 26, the timer circuit 25 counts the clock as shown in FIG. 2B to start time measurement and raise the timing signal TM to control the speed. It is supplied to the data forming means 20. Further, the switching signal SW is
As shown in C, during the start-up time tr from the start-up, the level becomes "H", and this time tr is the switch circuit 16
Is switched to the input terminal b. This time tr may be changed according to the locus of the data UP, but a maximum value of the time for start-up may be set and fixed as that value.

The rising speed control data forming means 20 is
Start-up speed control data UP based on the start pulse ST
The formation operation of is started. That is, the start-up speed control data forming means 20 first reads the ambient temperature information from the temperature sensor 21, the tape position information from the tape position detecting means 23, and the mechanical response information from the memory 24,
The rising speed control data UP (FIG. 2D) is formed from these pieces of information in synchronization with the timing signal TM. And
The rising speed control data UP is supplied to the sample hold means 28 via the adding means 27, and the timer circuit 2
5 is sampled and held by the sampling pulse Sp (FIG. 2E) from 5, and its output UPSH (FIG. 2F) is supplied to the PWM signal forming circuit 17 through the input terminal b of the switch circuit 16 to control the drive signal of the motor 1.

In this case, as shown in FIG.
When two or more frequency signals FG are generated as shown in G,
Since the actual speed error can be detected from this, the startup speed control data forming means 20 corrects the startup speed control data UP based on this actual speed error. Note that this correction need not be performed.

At the same time, the phase error at the previous stop is read from the memory 31, the rising phase data determining means 32 creates the rising phase data from the phase error at the previous stop, and the data is added by the adding means. 27 and is added to the startup speed control data UP.

As a result, within the start-up time tr measured by the timer circuit 25, the motor 1 rises to the target speed, and its rotation phase becomes close to the reference phase. Then, when the startup time tr has elapsed,
This is detected by the timer circuit 25, and the switch circuit 16
Is switched to the input terminal a side, and switched to steady servo control based on the speed error and phase error information Se from the speed and phase servo system 100. After this switching, the motor 1 stably rotates at the target rotation speed, and at the same time, rotates immediately locked to the reference phase.

When the start-up time tr has elapsed, the timer circuit 25 is reset, and the data forming operation of the start-up speed control data forming means 20 is completed.

Start-up speed control data forming means 20,
The tape position detecting means 22, the timer circuit 25, the phase data determining means 32, and the adding means 27 can also be realized by a microcomputer. In that case,
The start pulse ST interrupts the microcomputer, and the program having the operation content shown in the flowchart of FIG. 3 is executed.

That is, when an interrupt occurs, the startup and start-up routine 300 of FIG. 3 starts, the period of the frequency signal from the frequency generator 22 of the reel drive motor is read (step 301), and the tape position is calculated (step). 302). Next, the ambient temperature detected by the temperature sensor 21 is read (step 303), and mechanical response information is read from the memory 24 (step 304). Then, start-up speed control data is created from the read information (step 305). Next, the phase error at the time of the previous stop of the motor 1 is read from the memory 31 (step 306), and from this phase error, at the time of completion of the startup, the phase control data for making the lock phase close is formed and the startup is performed. It is added to the control data UPSH (step 307). Next, a PWM signal is formed from the start-up control data to which the phase control data is added (step 308),
This is supplied to the drive circuit 19 of the motor 1 via the low pass filter 18.

When the target rotation speed is reached, the startup and start-up routine 300 is ended, and the routine shifts to a steady speed and phase servo control routine. Also in this case, when the actual speed error is obtained by the frequency signal FG before the start-up, the start-up control data may be corrected in consideration of this error amount.

As described above, the capstan motor 1
Since the capstan motor 1 is started so as to draw a predetermined starting locus in consideration of the response characteristics at the time of starting, the motor 1 rotates at a higher speed than the target rotation speed (so-called overshoot ), The start-up speed becomes long, or the motor does not start up, so that the motor 1 can be started up quickly and satisfactorily. Moreover, since the phase error at the time of the previous motor stop is stored and the data for the phase control is added to the start-up control data based on the phase error, from the motor start to the phase lock. You can save time.

In the above example, the capstan motor is speed-controlled and phase-controlled.
It can also be applied to the case of speed control and phase control of the drum motor. In the case of a drum motor, a frequency generator is provided coaxially with the rotating shaft of the drum motor, and a pulse PG is generated at a rate of once per one rotation of the drum motor to generate a pulse PG indicating the rotation phase of the drum motor. A generator is provided. Then, in the speed servo, the frequency signal from the frequency generator is set to the reference frequency in the same manner as in the capstan motor, but in the phase servo, the pulse PG is synchronized with the reference signal of the frame period, for example. To be controlled.

In this case, as the phase error at the previous stop used at the time of start-up, the stop rotation angle position of the drum motor based on the rotation angle position at which the pulse PG is generated may be stored. The frequency generator generates N pulses per revolution of the drum motor.
When a number is assigned to each pulse generation position of the output frequency signal with reference to the rotation angle position at which the
Each rotation angle position of 1 / N of rotation can be specified from the number. This is because it is easy to know how much the position of the number is out of phase with the position of the pulse PG.

In the above example, the case where the present invention is applied to the servo circuit of the VTR motor has been described.
The present invention is not limited to the control of these motors, but can be applied to the speed control and phase control of motors used in audio tape recorders and disk devices, for example.

Further, in the case of the motor system which can stably start up to the target rotation speed even if the speed control at start-up according to the present invention is not performed, the phase control at start-up according to the present invention is performed. By using the data, it is possible to shorten the time until the phase lock at the time of starting the motor.

[0048]

As described above, according to the present invention, it is possible to prevent a situation in which the motor is smoothly started up, the rotation speed becomes excessive, and the motor does not start. Further, the phase servo can be locked quickly after starting the motor.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a servo circuit according to the present invention.

FIG. 2 is a timing chart for explaining the operation of the example of FIG.

FIG. 3 is a flowchart of an operation of an example of a main part of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 motor 2 frequency generator 17 PWM signal generating means 19 motor drive circuit 20 startup speed control data forming means 21 temperature sensor 22 frequency generator of reel motor 24 memory for storing mechanical response at startup 31 storing status response Memory 32 Phase data determination means 100 Speed and phase servo system 200 Start-up control system

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichiro Shimada Inventor Keiichiro 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (6)

[Claims] 1. A motor comprising a frequency signal generating means for generating a frequency signal according to the rotation speed of the motor, and controlling a drive signal supplied to the motor so that the frequency of the frequency signal becomes a reference frequency, In a servo circuit for rotating a motor at a predetermined target rotation speed according to the reference frequency, a memory circuit that stores mechanical response information at the time of motor start-up, which is determined by the motor and its load mechanism, and changes depending on the situation. In order to start the motor to the target rotation speed from one or a plurality of detection means for detecting information relating to the response at the time of starting the motor, information from this detection means, and information from the memory circuit. And a start-up speed control data forming means for forming start-up speed control data of Until reaching the rolling speed near the by raising rate control data, a servo circuit which is adapted to control the drive signal of the motor. 2. A means for obtaining a phase error according to a phase shift from a reference phase, wherein a drive signal supplied to the motor is controlled by the phase error to cause the motor to rotate in synchronization with the reference phase. In the servo circuit for performing the phase control so as to provide a means for storing the phase error at the time of the previous stop of the motor, at the time of starting the motor, based on the stored phase error at the time of the previous stop, the motor start A servo circuit configured to form a signal for the phase control at the time of raising. 3. A pulse generator for generating a pulse signal indicating the rotation phase of the motor, the drive signal being supplied to the motor so that the phase difference between the pulse signal and the signal indicating the reference phase has a predetermined relationship. In the servo circuit for controlling the phase so that the motor rotates in synchronization with the reference phase, the rotation angle position of the motor at the previous stop is detected with reference to the generation position of the pulse signal, A servo circuit, which is provided with a storing means, and which, when the motor is started up, forms a signal for the phase control at the time of starting the motor based on the stored information of the previously stopped rotation angle position. 4. A frequency signal generating means for generating a frequency signal according to a rotation speed of a motor, and means for obtaining a phase error according to a phase deviation from a reference phase, the frequency of the frequency signal and the reference frequency. The drive signal supplied to the motor is controlled by the speed error corresponding to the difference between the motor speed and the phase error, the motor rotates at a predetermined target rotation speed corresponding to the reference frequency, and In a servo circuit that controls to rotate in synchronization with a reference phase, a memory circuit that stores mechanical response information at the time of motor startup that is determined by the motor and its load mechanism, and a memory circuit that changes according to the situation One or a plurality of detecting means for detecting the information relating to the response, the information from the detecting means, and the detecting circuit from the storage circuit. Start-up speed control data forming means for forming start-up speed control data for starting the motor from the information and the target rotation speed; means for storing a phase error at the time of the previous stop of the motor; And a phase data determining means for forming a signal for the phase control at the time of starting the motor on the basis of the phase error at the time of the previous stop performed, from the time of starting the motor to the vicinity of the target rotation speed. During the period, the servo circuit is configured to control the drive signal of the motor by the data obtained by adding the signal from the phase data determination means to the start-up speed control data. 5. A frequency signal generating means for generating a frequency signal according to a rotation speed of the motor and a pulse generating means for generating a pulse signal indicating a rotation phase of the motor are provided, and the frequency of the frequency signal is a reference frequency. In addition, the drive signal supplied to the motor is controlled so that the phase difference between the pulse signal and the signal indicating the reference phase has a predetermined relationship, and the motor outputs a predetermined signal according to the reference frequency. A servo circuit for controlling the motor to rotate in synchronization with the reference phase while rotating at a target rotation speed, and a storage circuit for storing mechanical response information at the time of motor startup determined by the motor and its load mechanism. , One or a plurality of detecting means for detecting information relating to the response at the time of starting the motor, which changes depending on the situation, Starting speed control data forming means for forming starting speed control data for starting the motor to the target rotation speed from the information from the detecting means and the information from the storage circuit; A means for detecting the rotation angle position at the time of stop with reference to the generation position of the pulse signal, and storing it, based on the stored information of the last stop rotation angle position,
And a phase data determination unit that forms a signal for the phase control at the time of starting the motor, and from the time of starting the motor to the vicinity of the target rotation speed, in the startup speed control data, A servo circuit for controlling the drive signal of the motor by the data added with the data from the phase data determining means. 6. The method according to claim 1, 4 or 5, wherein when the information on the deviation of the frequency signal from the reference frequency is obtained during the period from when the motor is started to when the motor reaches the vicinity of the target rotation speed. A servo circuit in which control data for controlling the drive signal of the motor is corrected based on the information on the deviation.