JPS59226678A - Rotation controller - Google Patents

Abstract

PURPOSE:To accurately control the rotation of a rotation controller without so enhancing the accuracy of a detector itself by providng means for previously storing an error of the detector itself. CONSTITUTION:Rotating accuracy information of an N-pulse generator 3, stored in a memory 20 is set by the output pulse S1 of a 1-pulse generator 2, synchronously with a clock signal S2, and outputted to an adder 21. The output is the waveform for representing only the error of the N-pulse generator 3 itself. The adder 21 adds the output S4 of an integrator 8 and the signal inverted in polarity from the output S3 of the memory 20 to a signal S5. This signal S5 becomes the signal waveform representing the rotary error of a DC motor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotation control device, and particularly to a rotation control device for a rotating machine that requires highly accurate rotation control.

When trying to fix the rotational speed of a rotating machine at a desired rotational speed or change the rotational speed at a desired rate of change, the rotational speed of the rotating machine is usually detected and the detected signal is processed appropriately. A rotation control device is used that has a configuration in which the rotational power is applied to the rotary machine and then fed back to the drive circuit of the rotating machine. Among such rotation control devices, an example of the configuration of a rotation control device that has been conventionally used for a rotating machine that requires extremely high precision rotation control, such as a cylinder motor of a video tape recorder (VTR), is described below. As shown in the figure. In FIG. 1, reference numeral 1 denotes a rotating machine whose rotation is controlled, in this example a DC motor that drives a cylinder of a VTR. A 1-pulse generator 2 and an N-pulse generator 3 are mechanically coupled to this DC motor 1. 1 pulse generator 2 generates one pulse during one rotation of the DC motor 1, and N pulse generator 3 generates N pulses (N is an integer of 2 or more) during one rotation of the DC motor 1. Occur. The comparator 5 compares the phases of the output pulse of the 1-pulse generator 2 and the output signal of the synchronizing signal generator 4, and generates a voltage proportional to the phase difference. Compensation circuit 6 corrects the output voltage of comparator 5 and outputs it to amplifier 7. Amplifier 7 amplifies this signal and outputs it to adder 10. On the other hand, the output of the N pulse generator 3 is given to an integrator 8, which integrates this pulse and outputs a voltage proportional to the frequency of this pulse to an amplifier 9. Amplifier 9 amplifies this voltage and outputs it to adder 10. Adder 10 adds the outputs of amplifiers 7 and 9, and outputs this added signal to drive circuit 11.

The drive circuit 11 drives the DC motor 1 with its output, and the drive output changes according to the output signal of the adder 10. Among these, 1 pulse generator 2.
Synchronous signal generator 4. Comparator 5. The compensation circuit 6 and the amplifier 7 constitute a phase control circuit 12 (hereinafter referred to as an APC circuit) for controlling the rotational phase of the DC motor 1. In addition, N pulse generator 3. The integrator 8 and the amplifier 9 constitute a speed control circuit 13 (hereinafter referred to as AFC circuit) for controlling the rotational speed of the DC motor 1.

In this control operation, the APC circuit 12 compares the phase of the pulse generated by the 1-pulse generator 2 with the signal generated by the synchronization signal generator 4 that generates a synchronization signal indicating the desired rotation phase, An output corresponding to the difference is given to the adder 10. The AFC circuit 13 also obtains the frequency of the pulses generated by the N pulse generator 3, that is, the actual rotational speed information of the DC monitor 1, and outputs it to the adder 10. Therefore, the output of the adder 10 has information including the rotational speed error and the phase error, and based on this, the drive circuit 11 changes the drive output to the DC motor 1 and changes the rotational speed and phase. It constitutes a feedback system that controls the

By the way, in a rotating machine that requires a highly accurate rotational speed, an important issue is how much rotational precision can be obtained with this device.

For example, the rotation accuracy of a cylinder motor of a VTR is required to have an error of 0.01% or less. In the rotation control device shown in FIG. 1, the rotation information of the DC motor 1 is
Since it is obtained by pulse generator 2 and N pulse generator 3,
The accuracy of these two pulse generators is required to be extremely high both electrically and mechanically. In particular, since the N pulse generator 2 controls the rotational speed using this information,
The accuracy of this N-pulse generator 2 is such that it almost determines the accuracy of the rotational speed of the DC motor 1. For this reason, various improvements have been made to the N-pulse generator 2 in the past. FIGS. 2(a') and 2(b) are a plan view and a cross-sectional view taken along line A-A', respectively, showing an example of a specific configuration of this N-pulse generator 2. In the example, a set of gears 14 and 15 with uneven teeth are installed around the rotating part of the DC motor 1 and on the inner periphery of the fixed part facing it. However, in Fig. 2(a), Some of the teeth are omitted in the drawing. A permanent magnet 16 is attached to the inner gear 15, and a coil 17 is attached to the outer gear 14. When the DC motor 1 rotates, the The inner gear 15 also rotates, and the relative positions of the two sets of teeth change.

Therefore, the magnetic resistance between the inner gear 15 and the outer gear 14 changes with rotation, and the magnetic flux interlinking with the coil 17 also changes. Therefore, a voltage is generated in the coil 17 as the coil rotates. By adopting such a configuration, errors in rotation information due to eccentricity of the rotation of the inner gear are offset. However, 0.01%
In order to obtain rotational accuracy with the following error, extremely high eccentricity and gear tooth formation accuracy is required, and the tolerance range is approximately 10 μml! degree. This cannot be achieved only by the machining accuracy of each part, but requires adjustment during assembly. However, it is difficult to easily obtain the desired accuracy even with this adjustment during assembly. In this way, in the conventional rotation control l#A system, errors in the rotation itself and electrical and *mechanical errors in obtaining rotation information coexist.
The drawback is that the pulse generator must be highly accurate in order to obtain the desired rotational accuracy.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and provides a rotation control device that can perform rotation control with sufficient accuracy without requiring a high degree of accuracy in the configuration for obtaining rotation information. The purpose is to provide.

To summarize, the present invention provides a storage means for storing in advance the w4 difference of the configuration itself for obtaining rotation information, and in actual rotation control, this stored content is compared with the rotation information, and the rotation itself is A signal representing the deviation is extracted, and based on this signal, rotation 1lIII control is performed to provide 15 rotation control 1lWA position.

Hereinafter, the configuration and operation of embodiments of the present invention will be explained based on the drawings to clarify the details of the present invention. FIG. 3 is a block 14 schematically showing the configuration of an embodiment of the present invention. In FIG. 3, a motor to be rotationally controlled, for example, a VTR.
A DC motor 1, which is a cylinder motor, has a 1-pulse generator 2 and an N-pulse generator 3 mechanically connected to its rotating shaft, as in the case in FIG. The output of the first pulse generator 2 is compared with the output of the synchronizing signal generator 4 by a comparator 5, corrected by a compensation circuit 6, amplified by an amplifier 7, and output to an adder 10. This is the same as the case shown in the figure. On the other hand, N pulse generator 3
The output is integrated by an integrator 8, becomes a signal S corresponding to the rotation frequency, and is input to an adder 21. The output S1 of the 1-pulse generator 2 and the clock signal S2 obtained by multiplying the synchronization signal output from the synchronization signal generator 4 are input to the memory 20. The output S of the memory 20 is input to the adder 21. The adder 21 converts the polarity of S, and adds it to S to determine the difference between S4 and 88, and outputs a signal S corresponding to the difference to the amplifier 9. amplifier 9
The output of is input to the adder 10, and the adder 10 gives a signal corresponding to the sum of the two input signals to the drive circuit 11, and the drive circuit 11 generates a drive output to drive the DC motor 1 according to this signal. change. APC circuit 1 in Fig. 3
2' and AFC circuit 13' correspond to APC circuit 12 and AFC circuit 13 in FIG. 1, respectively.

-〇- Next, the operation of this embodiment will be explained based on Fig. 3 and Fig. 4, which is a time chart showing waveforms of each portion of Fig. 3. First, apply 0 to the DC motor 1 and N pulse generator 3.
Connect a standard rotating device with a rotational speed variation of less than 0.001%. This standard rotation device does not form part of the configuration of this device, but is only required at the time of adjustment of this #device, and is capable of achieving extremely high precision rotation speeds as described above. It is specially made to last. If a standard rotation device is connected to the DC motor 1 and the N-pulse generator 3 in this way, the output of the N-pulse generator 3 will contain almost no error due to the rotation itself, and the output of the N-pulse generator 3 will be The information contains only certain errors. N when rotating a standard rotating device with this configuration
The output of the pulse generator 3 is stored in a memory 20, for example, R
Store the OM in the built-in memory. In FIG. 3, there is no direct connection from the N pulse generator 3 to the memory 20, but this shows the configuration after adjusting this device, and the connection to the memory 2010- is not shown. When writing in advance, the output of the N-pulse generator 3 may be written into the memory 20 via a memory writing device. With the output of the N-pulse generator 3 when connected to the standard rotating device being stored in the memory 20 in this manner, the standard rotating device is removed. The third
The operation of the device shown in the figure will now be described. When the DC motor 1 rotates, the 1-pulse generator 2 and the N-pulse generator 3 generate 1 and N pulses per rotation, respectively. Among these operations, the operation of generating a phase difference signal based on the output of the 1-pulse generator 2 is the same as that in FIG. 1, and its explanation will be omitted. The output of the N pulse generator 3 is integrated in an integrator 8 to produce a signal S corresponding to the rotational frequency of the DC motor 1.

becomes. FIG. 4 shows the waveform of S, which is a signal containing both information based on the rotational error of the DC motor 1 and information corresponding to the electrical and mechanical error of the N pulse generator 3. be. On the other hand, the rotational accuracy information of the N-pulse generator 3 stored in the memory 20 is sensed by the output pulse S1 of the 1-pulse generator 2, and the clock signal @S2
, and is output to the adder 21. This output is a waveform representing only the error of the N pulse generator itself, as shown in S in FIG. have. The adder 21 adds the output S of the integrator 8 and the signal obtained by inverting the polarity of the output S of the memory 20 to obtain a signal S5.

As shown in FIG. 4, this S is a signal waveform representing the rotational error of the DC motor 1 itself. This signal Ss is amplified and added to the output of the amplifier 7, resulting in no change in the drive output, and the process is the same as in the case of FIG. This rotation control device controls the rotational speed and rotational phase of the DC motor 1 using the feedback system described above.

In the above embodiment, the rotation control of the Schilling motor of the VTR was explained, but the capstan rotation 11+1
It can also be applied to rotation control of general rotating machines such as JllI.

Furthermore, although a configuration using a set of gears as a pulse generator has been shown, the present invention is not limited to this, and any means may be used as long as it detects the actual rotational speed and its phase.

As explained above, according to the present invention, means is provided for storing in advance the W4 difference of the detection device itself that detects the rotation speed of the rotating machine, and the rotation control is performed using the stored information. , fluctuations in the rotational speed itself can be completely separated,
High-precision rotation control can be achieved without significantly increasing the precision of the detection device itself, such as processing precision and assembly precision. In addition, the information stored in the memory is
Since the information indicates the error in the i-mark, the same degree of accuracy can be achieved as a control device regardless of variations in the accuracy of the detection device of each product. Adding memory increases the cost of the product, but on the other hand, the cost of the detection device decreases, so
Overall, the cost increase is extremely small.

However, in the above embodiment, a pulse generator using one set of gears is considered as the rotational speed detection device, and the machining accuracy of this pulse generator is to some extent low, and it is possible to use a conventional pulse generator without assembly adjustment. It is possible to provide a rotation control device that can maintain rotation accuracy higher than that of the rotation control device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing the configuration of a conventional rotation control device. FIGS. 2(a) and 2(b) are a plan view and a sectional view taken along the line AA', showing a part of a pulse generator for detecting the rotational speed of a rotating machine, respectively. FIG. 3 is a block diagram schematically showing the configuration of an embodiment of the present invention. FIG. 4 is a waveform diagram showing waveforms of various parts in the embodiment of FIG. 3. In the figure, 1 is a DC motor, 2 is a 1-pulse generator, 3 is an N-pulse generator, 4 is a synchronizing signal generator, 5 is a comparator, 6 is a compensation circuit, 7 and 9 are amplifiers. 8
is an integrator, 10 and σ2.1 are adders, 11 is a drive circuit, 12 and 12- are phase control circuits, 13 and 13- are speed control circuits, and 14 and 15 are pulse generators, respectively. 14 for the outer and inner gears of the container, 16 for the permanent magnet, 17 for the fill, 20 for the memory, and 14 for each.
- Show. Statement 15 - Second Section Figure 4 ≦ - Procedural amendment (self-initiation 1, case description Japanese Patent Application No. 58-98917 2, name of the invention Rotation control device 3, person making the amendment Relationship with the case Patent application Address: 2-3, Marunoshiratama-chome, Chiyoda-ku, Tokyo Name (601,) Mitsubishi Electric Co., Ltd. Representative: Hitoshi Katayama 4, Agent Address: Mitsubishi Electric, 2-2-3, Marunouchi, Chiyoda-ku, Tokyo Co., Ltd. 5, Detailed explanation of the invention in the specification to be amended, 6, ``About 10μ'' on page 7, line 13 of the specification of the contents of the amendment, [about 10μ]
Corrected to about μl J. Above 2-

Claims (3)

[Claims] (1) A rotation control device for controlling the rotation of a rotating machine, comprising: a drive means for controlling the rotating machine; a rotation speed detection means for detecting the rotation speed of the rotating machine; storage means for storing in advance an output value of the rotational speed detection means when the speed is detected by the rotational speed detection means; a reading means for reading out the stored contents of the storage means in synchronization with the rotation of the rotating machine; speed difference signal generation means for generating a signal representing the difference between the output of the rotational speed detection means and the output of the succession means, and the drive means is responsive to the output of the speed difference signal generation means. A rotation control device whose output changes. (2) rotational phase detection means for detecting the phase of rotation of the rotating machine; synchronization signal generation means for generating a synchronization signal for the rotation of the rotary machine; an output of the rotational phase detection means; and an output of the synchronization signal generation means. further comprising phase difference signal generation means for generating a signal representing a difference between the rotational phase detection means and the phase synchronization signal generation means, wherein the readout means reads the data from the storage means in synchronization with the output of the rotational phase detection means and the output of the phase synchronization signal generation means. 2. The rotation control device according to claim 1, wherein the drive output of the drive means changes in response to the output of the phase difference signal generation means. (3) The rotation speed detection means includes an N pulse generator that generates N pulses (N is an integer above 2L1.) per rotation of the rotating machine, and integrates the output of the N pulse generator. and an integrating circuit, the rotational phase detection means detecting a rotational phase of one rotation per rotation of the rotating machine.
The rotation control device according to claim 1 or 2, comprising a one-pulse generator that generates one pulse.