JPH01177886A - Automatic rotation controller - Google Patents

Abstract

PURPOSE:To prevent the sudden variation of the revolution of a motor by respectively converting the error signal of a revolution signal and a reference signal and the revolution signal into digital signals and synthesizing these signals and digital-filtering a synthetic digital signal and converting it into an analog signal. CONSTITUTION:An error detector 2 compares a revolution signal generated from a frequency generator 9 and a reference signal, and adds an error signal to an A/D converter 4 through a low-pass filter 3. The revolution signal generated from the frequency generator 9 is added to an A/D converter 10. A digital signal processing circuit 5 digital-filters both digital signals, and outputs digital processing signals to a driver circuit 7 through a D/A converter 6. Accordingly, the effect of mechanical disturbance such as the vibrations of a car can be compensated in a CD player, etc., for car loading.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to compact disc players, etc.
The present invention relates to an automatic rotation control device used to control the rotation speed of a rotation means such as a motor.

(Summary of the Invention) The present invention provides a reference signal generator, an error detection circuit, a low-pass filter, an analog/digital converter, a digital signal processing circuit, a digital This system is equipped with an analog converter, a drive circuit, and a frequency generator to detect mechanical disturbance components and improve the gain in the frequency band of nuclear disturbance components.

(Prior Art) Conventionally, in this type of automatic rotation control device, for example, Japanese Patent Application Laid-Open No. 60-134787 and Japanese Patent Application Laid-Open No. 60-134
As disclosed in Japanese Patent No. 7879, there is an automatic motor control device that can prevent the motor from causing sudden rotational fluctuations due to dust attached to the disk surface or mechanical disturbances.

(Problems to be Solved by the Present Invention) However, in the conventional device described above, control errors are large for disturbances with high frequency components, that is, disturbances with high vibration frequencies.
Furthermore, when the automatic control system gain (hereinafter referred to as loop gain) of high frequency components is increased, the characteristics of the automatic control system generally have a quadratic transfer characteristic, so there is no phase margin and the loop no longer converges.

Furthermore, since the required control band in a normal control mechanism is a sufficiently low frequency, it is not possible to reduce the loop gain in the low frequency range and improve the gain in the high frequency range. Therefore, it is necessary to set up a means to prevent relatively high frequency disturbances (frequency higher than the natural frequency of the closed loop) from being added to the loop, but this method has the disadvantage of requiring a huge amount of cost to implement. .

(Means for Solving the Problems) In order to solve the above-mentioned conventional drawbacks, the present invention provides a reference signal generator that generates a signal serving as a reference for the number of rotations of a rotating means such as a motor, and a a frequency generator that generates an electrical signal with a frequency corresponding to the frequency; an error detection circuit that compares the reference signal generated from the reference signal generator with the electrical signal generated from the frequency generator; and the error detection circuit. A low-pass filter that passes only the low frequency components of the analog signal output from the circuit;
a first analog/digital converter that converts an analog signal output from the filter into a digital signal; and a second analog converter that converts the analog signal of a frequency corresponding to the rotational speed generated from the frequency generator into a digital signal. /a digital converter; a digital signal processing circuit that synthesizes the digital signals converted by the first and second analog/digital converters and performs digital filtering; A digital/analog converter for converting into an analog signal and a drive circuit for driving the rotating means with the analog signal output from the digital/analog converter are provided.

(Operation) The control device configured as described above operates as follows. First, an error detection circuit generates a reference signal to be a reference and compares it with an electric signal of a frequency corresponding to the number of rotations generated from a frequency generator attached to the rotating means. A digital signal obtained by converting the analog signal generated from the error detection circuit into a digital signal, and a digital signal obtained by converting the analog signal output from the error detection circuit into a digital signal are input to a digital signal processing circuit and synthesized. The synthesized digital signal is subjected to digital signal processing such as digital filtering, the processed digital signal is converted to an analog signal, the analog signal is input to a drive circuit, and the output from the drive circuit drives the rotating means. , the rotation speed of the rotation means is controlled.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an automatic rotation control device according to the present invention. In FIG. 1, 1 is a reference signal generator that generates a reference signal, such as a VCO (automatic voltage controlled oscillator), to determine the rotation speed of a motor, etc., and 2 is a reference signal generator that generates a reference signal, which will be described later. An error detection circuit that compares the electrical signal generated from the generator 9 with a frequency corresponding to the rotational speed of the motor.

3 is a low-pass filter that passes only the low frequency of the output signal from the error detection circuit; 4 is a first analog signal converter that converts the analog signal from the low-pass filter;
A digital converter; 5 is a digital signal processing circuit for digitally filtering the digital signal; 6 is a digital/analog converter for converting the digitally processed signal back into an analog signal; 7 is a drive for driving a motor 8, which is a rotating means. The circuit includes a frequency generator 9 that generates an electrical signal with a frequency corresponding to the number of rotations of the motor 80, and an analog/digital converter 10 that converts an analog signal from the frequency generator 9 into a digital signal.

First, a normal operation in which the automatic rotation control device is not subjected to mechanical disturbances such as vibrations of an automobile will be explained. At the start of operation, the signal generated from the reference signal generator l such as a VCO is sent to the error detection circuit 2, and since the signal from the frequency generator 9 is not fed back at this point, the signal is unprocessed. Only the low frequency components of the output from the error detection circuit are passed through a low-pass filter 3 and converted into a digital signal by a first analog/digital converter 4. The signal then passes through the digital signal processing circuit 5 as it is, is converted back to an analog signal by the digital/analog converter 6, and is input to the drive circuit 7, where the motor 8 is driven by the drive signal.

Therefore, as the motor 8 rotates, an analog signal having a frequency corresponding to the rotation speed is generated from the frequency generator, and the analog signal is fed back to the error detection circuit 2.

At the same time, the analog signal is converted into a digital signal by the second analog/digital converter IO, and a loop is formed in which the analog signal is fed back to the digital signal processing circuit 5.

Here, the error detection circuit 210-pass filter 3,
The digital signal that has passed through the first analog/digital converter 4 and the digital signal that has passed through the frequency generator 9 and the second analog/digital converter are equivalent digital signals, and are synthesized by the digital signal processing circuit. Since the digital signal subjected to the digital filtering process is also equivalent to the digital signal, the analog signal converted by the second digital/analog converter 6 is input to the drive circuit 7, but the signal from the drive circuit 7 is The rotational speed of the motor 8, which is a rotating means driven by the output, is maintained at a constant speed without being affected in any way.

Next, the case where there is a mechanical disturbance will be explained.

When the disturbance is detected by the frequency generator 9, the analog output signal from the frequency generator 9 is fed back to the error detection circuit as in the normal case, but it is different from the reference signal generated from the reference signal. At the same time as being input to the error detection circuit for comparison, it is converted into a digital signal by the second analog/digital signal converter lO, and the comparison output from the error detection circuit mentioned above is input to the low-pass filter 3. The first digital signal that passes only the low frequency components and is converted by the first analog/digital converter 4 is synthesized by the digital signal processing circuit 5 and subjected to digital filtering signal processing, that is, as shown in FIG. In the diagram showing the improved characteristics (open loop transfer characteristics) of the digitally processed signal, the control error in this band is improved by increasing the gain in the portion indicated by the dotted line.

Then, the digital signal output from the digital signal processing 5 is converted into an analog signal again by the digital/analog converter 6, and is inputted to the drive circuit 7, which drives the motor 8. A signal of a frequency different from that in the normal case generated from the frequency generator 9 works to control the rotation speed of the motor 8 and is fed back to the reference signal generator 1 and the error detection circuit 2, and as a result, the machine This controls the motor to maintain its normal rotational speed even if there is a disturbance.

(Effects) Therefore, 1. According to the automatic rotation control device according to the present invention, 1. It is possible to provide an inexpensive automatic rotation control device that can compensate for the influence of mechanical disturbances such as car vibrations in, for example, an in-vehicle CD player. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment according to the present invention, and FIG. 2 is a frequency improvement characteristic diagram according to the present invention. l...Reference signal generator, 2...Error detection circuit, 3.
...Low pass filter, 4...Analog/digital converter, 5...Digital signal processing circuit, 6...Digital/analog converter, 7...Drive circuit, 8...
Motor-19...Frequency generator, lO...Analog/digital converter. Agent Patent attorney Takeshi Sugiyama (1 other person) 1 map, 2 maps

Claims (1)

[Scope of Claims] 1. A reference signal generator that generates a signal serving as a reference for the rotation speed of a rotating means such as a motor, and a frequency generator that generates an electrical signal with a frequency corresponding to the rotation speed of the rotating means. , an error detection circuit that compares a reference signal generated from the reference signal generator and an electrical signal of a specific frequency generated from the frequency generator; and a low frequency component of the analog signal output from the error detection circuit. a first analog/digital converter that converts the analog signal output from the low-pass filter into a digital signal; and a first analog/digital converter that converts the analog signal output from the low-pass filter into a digital signal; a second analog/digital converter that converts an analog signal into a digital signal;
a digital signal processing circuit that synthesizes digital signals converted by the digital converter and performs digital filtering processing; a digital/analog converter that converts the digital signals output from the digital signal processing circuit into analog signals; and a drive circuit for driving the rotation means with an analog signal output from an analog converter.