KR0124655B1 - Motor control apparatus - Google Patents

Abstract

A motor control apparatus is provided that improves a motor controlling capacity by correcting a cyclic disturbance frequency even in case that it is not 1/n (n : natural number) of a sampling frequency. The motor control apparatus, having a motor, a learning controller for correcting a rotational speed error signal generated when it is generated, a speed controller for detecting the rotational speed of the motor corrected and outputted from the learning controller, a phase controller for detecting a position of the motor, an operator for subtracting the rotational speed and the position of the motor detected at a predetermined speed and a target position, and a driving unit for compensating the speed and the position of the motor according to the output from the operator and driving the motor, includes a first adder for adding the rotational speed error signal of the motor to a disturbance restraining frequency, correcting the cyclic disturbance frequency even in case that it is not 1/n (n : natural number) of a sampling frequency, and outputting a corrected signal (Y), a second adder for adding the rotational speed error signal to a frequency movement compensating function (g(Z)) to be fedback, a frequency movement compensating unit for delaying the output from the second adder through n number of delays and m number of delays, multiplying it by each weight value (k,l) and adding them, and passing a divider having a predetermined gain (1/(k+1) to output it as a frequency movement compensating function (g(Z)), and a multiplier for multiplying the frequency movement compensating function (g(Z)) by a predetermined gain (K) to output it as a disturbance restraining frequency to the first adder, where the transmission function between the inputted error signal (X) and the correct signal (Y) is expressed in the following equation: Y(Z)/X(Z)= {1+(K-1)g(Z)}/{1-g(Z)}.

Description

Motor control unit

1 is a block diagram of a general motor control apparatus.

2 is a gain characteristic diagram of a board diagram when the motor is controlled by the first diagram.

3 is a spectral diagram of rotational error due to a general periodic disturbance component.

4 is a board diagram for suppressing the periodic disturbance generated in FIG.

FIG. 5 is a spectral diagram of rotational error by removing the periodic disturbance component from FIG.

6 is a block diagram of a motor control apparatus including a conventional learning controller.

7 is a detailed block diagram of the learning controller of FIG.

(B) is a detailed block diagram of the delay part (Z) ^-n of (a).

8 is a characteristic diagram showing an embodiment of the frequency characteristic of the learning controller of FIG.

9 is a detailed block diagram of the learning controller in the motor control apparatus according to the present invention.

10 is a detailed block diagram of the frequency shift compensation unit of FIG.

(b) is a simplified block diagram of (a) above.

11 is a characteristic diagram illustrating an embodiment of a learning controller frequency characteristic according to the present invention.

12 is a block diagram showing a conventional notch filter.

13 is a frequency characteristic diagram of the notch filter of FIG.

14 is a block diagram of a notch filter in the motor control apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

10: learning controller 11: speed control unit,

12: phase control unit 13: arithmetic unit,

14: motor drive unit 91, 97: an adder,

93: frequency shift compensation unit 94: multiplier,

101, 102: delay unit 103, 104: multiplier,

105: adder

106: divider, M: motor, g (Z): frequency shift compensation function, k, l: weight of each frequency.

The present invention relates to a motor control device, and more particularly, in a device employing a motor such as a video cassette recorder (hereinafter referred to as a VCR), a periodic disturbance occurrence frequency is 1 / n of a sampling frequency (n Is a natural number) to a motor control device capable of suppressing disturbance.

1 is a block diagram of a general motor control apparatus. When the motor M is driven, the speed controller 11 detects the speed using a frequency generator (FG), and the phases of the speed controller and the motor are adjusted. A phase control unit 12 for detecting, a calculation unit 13 for subtracting the drive speed and the position of the motor detected by the speed control unit 11 and the phase control unit 12 from the set speed and the target position, and the calculation unit 13 Comprising the speed and position of the motor (M) in accordance with the output of the motor driving unit 14 for driving the motor.

In FIG. 1 configured as described above, when the motor M rotates, the speed control unit 11 detects the driving speed of the motor using the FG, and the phase control unit 12 detects the driving position of the motor.

The calculation unit 13 calculates a speed deviation by subtracting the speed detected by the speed control unit 11 from a preset rotational speed, and subtracts the position detected by the position control unit 12 from a target position to obtain a position deviation. After that, it outputs to the drive unit 14. The driving unit 14 drives the motor M through a servo (not shown) after compensating for the speed deviation and the position deviation generated by the calculation unit 13.

At this time, the servo performs a software servo using a digital servo or a microcomputer.

When the motor M is controlled as shown in FIG. 1, the gain characteristic of the board diagram is as shown in FIG.

That is, in general, the disturbance components of the motor M are in the low frequency region due to mechanical factors.

Therefore, as shown in the board diagram of FIG. 2, the gain is increased at low frequency to suppress disturbance of low frequency components.

However, if the gain is made large, the control becomes unstable due to the characteristics of the speed and phase control itself gain margin, phase margin, etc., so the controller should be designed at an appropriate level.

In addition, the first diagram described above does not completely suppress the periodic disturbance components caused by the torque ripple, the gears, the mechanical problems, etc., and thus appears as a rotation error component of the motor M. It will have a bad effect.

The spectrum of the rotational error caused by the periodic disturbance component is shown in FIG.

Therefore, in order to suppress the periodic disturbance as shown in FIG. 3, there is a method of increasing the gain at f1 where the periodic disturbance component exists as in the board diagram of FIG.

Then, as shown in the rotation error spectrum of FIG. 5, periodic disturbance occurring at f1 can be suppressed.

That is, when the learning controller 10 is inserted between the speed controller and the motor M as shown in FIG. 6 to increase the gain at f1 where periodic disturbance components exist as shown in the board diagram of FIG. 4, the gain generated at f1 as shown in FIG. Periodic disturbance components are suppressed as shown in FIG.

Here, the learning controller 10 is a kind of digital filter.

Detailed configuration diagram of the learning controller 10 is the same as FIG.

That is, the adder 71 which adds the speed control signal including the frequency variation component of the rotation detection signal detected by the FG to the feedback signal while the motor M rotates, and delays the output of the adder 71 A delay unit 73 for feeding back to the adder 71 and outputting the output to the rear end; a multiplier 75 for multiplying the gain K of the learning controller by the output of the delay unit 73; and the speed control. The adder 77 adds a signal and an output of the multiplier 75.

In this case, the delay unit 73 is composed of n delay units Z ⁻ⁿ as shown in FIG. 7 (b), and the number of delay units of the delay unit 73 varies according to the position of the periodic disturbance frequency. .

That is, Z- ⁿ is a transfer function of the delay unit 73, and n represents the number of pulses of the FG signal. In FIG. 7 configured as described above, the transfer function is as follows.

In this case, X (Z) represents the Laplace transform value of the input signal of the learning controller 10, Y (Z) represents the output signal, and K is the gain of the learning controller 10.

And when the sampling frequency of the rotation detection signal of the motor M is called f _sampling , the disturbance suppression frequency f _reject for suppressing the periodic disturbance component is

Accordingly, when the sampling frequency f _sampling is 100 Hz and the periodic disturbance is 100 Hz, the number of delay units 73 used in the learning controller 10 of FIG. 7 is as follows.

Therefore, the learning controller 10

It can be configured as.

Here, when K = 1/8, the frequency characteristic of the learning controller 10 is shown in FIG. 8 to suppress the disturbance of the 100 Hz component.

At this time, the increase in the individual at the frequency of 200, 300, ... as shown in FIG. 8 is a phenomenon that appears because the learning controller 10 is a digital filter.

However, the learning controller as shown in FIG. 7 has a disturbance suppression frequency f _reject .

Because it is decided,

There was a problem that the periodic disturbance cannot be used unless it is 1 / n of the sampling frequency.

That is, since n is a natural number, when the periodic disturbance frequency does not fall to an integer, even if disturbance occurs, it cannot be suppressed.

Therefore, the use of the learning controller is limited, and in order to suppress the disturbance by using the learning controller, additional problems such as changing the sampling frequency by changing the number of FG magnetized magnets of the motor occur.

The present invention is to solve the above problems, an object of the present invention is to add the m (m is a natural number) delay to n (n is a natural number) delay to the average filter effect of Z ^-n and Z ^-m The present invention provides a motor control device capable of compensating even when a periodic disturbance occurrence error frequency is not 1 / n of a sampling frequency by performing frequency shift.

A characteristic of the motor control apparatus according to the present invention for achieving the above object is the first to output the corrected signal by correcting even when the periodic disturbance frequency is not a natural number by adding the rotational speed error signal and the disturbance suppression frequency of the motor An adder, a second adder that adds a rotation speed error signal of the motor and a frequency shift compensation function fed back, and delay the output of the second adder through n delayers and m delayers, multiply each weighter, and add The learning controller comprises a frequency shift compensator for passing a divider having a predetermined gain and outputting the frequency shift compensation function as a frequency shift compensation function, and a multiplier outputting the frequency shift compensation function to the first adder as a disturbance suppression frequency. It is.

Hereinafter, a preferred embodiment of a motor control apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

9 is a configuration diagram of the learning controller in the motor control apparatus according to the present invention, in which the frequency shift compensation function g fed back to the rotation speed error signal X (Z) detected by the FG while the motor M rotates. An adder 91 that adds (Z)), and the adder 91 delays an output using n delayers and m delayers to obtain a frequency shift compensation function g (Z) to obtain the adder 91. And a multiplier 95 for multiplying the gain k of the learning controller by the frequency shift compensator 93 for outputting to the rear stage and simultaneously outputting the signal to the rear stage. And an adder 97 for adding the signal and the output of the multiplier 95 to compensate for the rotational speed error signal of the motor M. FIG.

10A is a detailed circuit diagram of the frequency shift compensator 93, in which a first delay unit 101 including m delay units and nm delays connected to the first delay unit 101 are illustrated. A second multiplier 102 composed of a group, a first multiplier 103 multiplying a weight 1 by a transfer function Z ^−m of the first delay unit 101, and the second delay A second multiplier 104 that multiplies the transfer function Z ⁻ⁿ of the unit 102 by the weight k, and an adder 105 that adds outputs of the first and second multipliers 103 and 104; And a divider 106 that multiplies the output of the adder 105 by a value 1 / (k + 1) for setting gain to 1 in another frequency band.

Here, n> m, k and 1 are weights of respective frequencies, and k and l use natural numbers to facilitate digitization and software. And, Z ^-m is the transfer function of the first delay unit 101, Z ^-n is the transfer function of the second delay unit 102.

According to the present invention configured as described above, the rotation speed error signal detected by the FG while the motor M rotates includes the first and second delay units 101 and 102 composed of n and m delay units, respectively, through the input terminal a. After roughing, the first and second multipliers 103 and 104 are multiplied by the weights of k and l, respectively, added by the adder 105 and then passed through the divider 106 of 1 / (k + l) to the output terminal b. Will be printed).

That is, the present invention transfer function of the conventional learning controller

To,

Transform into.

Therefore, in the above equation, in the conventional learning controller, the frequency of the learning controller is determined by ⁿ as g (Z) = Z ⁻ⁿ . However, in the present invention, m is added to ⁿ delayers so that Z delays of Z ⁻ⁿ and Z ^−m The frequency shift is performed by the average filter effect to selectively control learning at an arbitrary frequency.

Therefore, the transfer function of the learning controller according to the present invention

ego,

The frequency shift compensation function g (Z)

to be.

Here, n and m are natural numbers, k and l are weights of the respective frequencies, and k + 1 of the denominator is a value for setting the gain to 1 since the DC gain may rise in another frequency band where disturbance does not occur.

At this time, the disturbance suppression frequency (f _reject) capable of suppressing a periodic disturbance is as follows assuming that the sampling frequency f _sampling.

Therefore, by selecting n, m near the desired frequency from equation (4), and selecting the appropriate k, l, it is possible to suppress the periodic disturbance frequency even if it occurs in a non-natural number.

On the other hand, the periodic disturbance frequency as described above

Since it exists in between, if you can express the above (Equation 3) more easily,

(Eq. 5).

If the frequency shift compensator 93 as shown in Equation 5 is designed, it can be configured as shown in FIG. Here, FIG. 10B is more convenient to implement than FIG. 10A.

That is, FIG. 10 (b) obtains the position at which the previous value is obtained by the frequency shift compensator 93 at the position immediately before.

In this case, let the sampling frequency be 1000 Hz, and if the frequency shift compensation function g (Z) is configured as follows,

Disturbance suppression frequency (f _reject ),

Becomes

The frequency characteristic is shown in FIG. 11 to suppress the periodic disturbance component generated at 103.7 Hz.

As described above, the present invention can suppress the periodic disturbance frequency even if it occurs where it is not a natural number.

On the other hand, there is a notch filter that reduces gain in a specific frequency part in a different concept from the learning controller. This notch filter is a filter used to ignore the error generated in the part because it is not disturbance when the FG sensor itself is wrong and the problem occurs with the FG sensor itself.

The conventional notch filter is a feedback route composed of the subtractor 21, the adder 22, the delayer 23, and the multiplier 24 as shown in FIG. 12, and is detected by the FG while the motor M rotates. When the rotated speed error signal is input through the input terminal X, the speed control signal from which the frequency variation component of the rotation detection signal is removed is output to the output terminal Y.

That is, the transfer function of FIG.

(Eq. 6),

In this case, when the notch filter is a sampling f _sampling ,

f _notch = f _sampling / n, where the frequency characteristics are shown in FIG.

In this case, since FIG. 12 is applied only to a specific frequency, if an error occurs in a place where the FG sensor itself is not a natural number, the error is not ignored and adversely affects the performance of the system.

Accordingly, as another embodiment of the present invention, a conventional notch filter configured as shown in FIG. 12 is configured as shown in FIG.

,

Speaking of

The notch frequency f _notch is

Since the notch frequency can be changed arbitrarily, even if the error frequency generated due to the problem of the FG sensor itself occurs in a non-natural number, it can be ignored.

On the other hand, the present invention can be applied digitally or software to control of devices such as VCRs.

As described above, according to the motor control apparatus according to the present invention, the frequency shift compensator is configured by adding m (m is natural numbers) delay units to n (n is natural numbers) delay units and the following equation,

(k, l) is a weight for each frequency, and the k + 1 in the denominator is the value for the gain to one another in the frequency does not occur a disturbance) Z ^-n and frequency shift in the average filter effect of the Z ^-m In this way, even if periodic disturbance occurs at a frequency other than a natural number, correction is possible, thereby improving motor control performance.

In addition, system performance such as a VCR employing such a motor is also improved.

Claims (3)

A motor, a learning controller for correcting the rotational speed error signal generated when the rotational speed error signal of the motor is generated, a speed control unit for detecting the rotational speed of the motor corrected and output from the learning controller and detecting the position of the motor In the motor control device comprising a phase control unit, a calculation unit for subtracting the rotation speed and position of the motor detected at the set speed and the target position, and a drive unit for driving the motor by compensating the speed and position of the motor according to the output of the calculation unit, A first adder for adding the motor rotation speed error signal X and the disturbance suppression frequency to correct the periodic disturbance frequency even if it is not 1 / n of the sampling frequency (n = natural number) and output the corrected signal Y And a second adder for adding a rotation speed error signal of the motor and a frequency shift compensation function g (Z) fed back, and outputting the second adder. Is delayed through n delayers and m delayers, multiplied by their respective weights (k, l), added, and passed through a divider with a predetermined gain (1 / (k + 1)) to obtain a frequency shift compensation function g (Z The learning controller comprises a frequency shift compensator outputting as a)) and a multiplier for multiplying the frequency shift compensation function g (Z) by a predetermined gain K to output the disturbance suppression frequency to the first adder. The transfer function between the input error signal (X) and the correction signal (Y) Motor control device characterized in that. The frequency shift compensation function g (Z) sms of the frequency shift compensation number, Motor control device characterized in that. Where nm is the weight of each frequency. The frequency shift compensation function g (Z) of claim 1, wherein Motor control device characterized in that. Where k and l are the frequency weights.