JPH03218285A - Motor controller - Google Patents

Abstract

PURPOSE:To improve constant speed control of a motor by providing means for relatively increasing the integrating control component of a feedback control signal for the motor when a judgment is made that the rotational speed of motor is reached the steady region. CONSTITUTION:A control section 14 calculates a proportional control voltage e(t) every time when the number of revolution for control is determined, and thus calculated voltage is stored. The state of steady region flag is then judged and the steady region flag is reset. If the rotational speed of a motor 10 is in the transient response region, coefficient B is set equal to Bs and the steady region flag is set, whereas when the rotational speed of motor is reached the steady region, the coefficient B is set equal to BL and the control voltage V0 is calculated according to the formula. Since the ratio of integrating control component in the control signal is increased relatively, a stable constant speed control is realized.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention relates to a motor control device, and in particular, to a motor control device that can accurately determine whether or not the motor rotation speed has reached a steady state region. The present invention relates to a motor control device for controlling the rotational speed of a motor at a constant speed so that it matches a target speed.

Conventional technology> PLL (phas
e-locked loop) control methods and integral control methods are well known.

Each of the above-mentioned control methods is sufficiently effective as constant speed control after the motor reaches a steady state region.

6. Problems to be Solved by the Invention> By the way, in the transient response region where the rotational speed of the motor is increased to a steady state region, proportional control is generally used to apply a voltage proportional to the speed difference between the target speed and the detected speed to the motor. will be held. Then, the detected speed is a predetermined percentage of the target speed,
For example, it may be determined that the motor rotation speed has reached a steady range by reaching within 95%, or an acceleration component may be calculated based on the previous detected speed and the current detected speed, and the motor rotation speed may be determined to be steady based on that value. It was determined that the area had been reached.

However, in the method of determining that the motor rotation speed has reached a steady range when the detected speed has reached a predetermined percentage (for example, 95%) of the target speed, for example, if the load is larger than the set value, the motor rotation speed is lower than the target speed. In some cases, the speed stabilizes at a low speed (for example, 90% of the target speed), and it is not determined that the steady state has been reached for a long time.

Furthermore, in the method of calculating acceleration and determining whether it has reached a steady state based on that value, even in the transient response region, it may be determined that the acceleration component has become almost 0 due to noise, vibration, etc. There were cases where it was erroneously judged that the temperature had entered the steady state region.

As in the former case, if it is determined that the motor rotation speed has not reached the steady range, PLL control or integral control cannot be entered, and even if PLL control or integral control is entered, the The shot is violent and it takes time for the motor rotation speed to stabilize.

In addition, as in the latter case, if it is determined that the stationary region has been reached even though it is in the transient response region due to an erroneous judgment, the PLL
Even if control is started, normal control cannot be performed.

Therefore, in a motor control device, it is necessary to be able to accurately detect when the motor rotational speed changes from a transient response region to a steady state region.

Furthermore, after the motor rotation speed reaches a steady range, it must be controlled so that the motor rotation speed does not deviate from the target speed, but with conventional devices, the detected motor rotation speed is affected by noise, etc. This also has the disadvantage that it is difficult to accurately detect the motor rotational speed, making constant speed control difficult.

Therefore, this invention was made to eliminate each of the above-mentioned drawbacks, and it is possible to accurately detect when the motor rotation speed has reached the steady range from the transient response range, and it is possible to accurately detect when the motor rotation speed has reached the steady range from the transient response range. Even if the speed detection signal fluctuates temporarily due to noise, etc., the motor rotation speed can be accurately detected without being affected by the fluctuation, and the constant speed control of the motor can be performed with good followability. The purpose of the present invention is to provide a motor control device that can perform the following functions.

Means for Solving the Problem> The first invention uses a control signal that includes a proportional control component based on a speed difference and an integral control component that integrates the speed difference so that the motor rotation speed becomes equal to the command speed. A motor control device that performs feedback control of a motor, comprising: a data calculation means that calculates data regarding the motor rotation speed at each predetermined timing;
It has a plurality of storage areas that can store data for a plurality of times in chronological order, and each time data regarding the motor rotation speed is calculated by the data calculation means, the already stored data is sequentially shifted one by one and stored in the most recent order. Storage means for discarding old data and storing the data calculated this time in the latest data storage area, data corresponding to the center of the size of the data of multiple times stored in the storage means, and the latest data calculated this time. and determine whether the motor rotation speed has reached a steady range based on whether the latest data corresponds to the data corresponding to the middle of the magnitude or is within a predetermined range with respect to the data. determining means; and control component changing means for relatively increasing an integral control component among control signal components for feedback controlling the motor when the determining means determines that the motor rotation speed has reached a steady range. A motor control device characterized by comprising:

Further, the second invention provides a motor that performs feedback control of the motor using a 10 control signal including a proportional control component based on a speed difference and an integral control component that integrates the speed difference so that the motor rotation speed becomes equal to the command speed. The control device includes a data calculation means for calculating data regarding the motor rotation speed at each predetermined timing, a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in order of newest, and a data calculation means for calculating data regarding the motor rotation speed. Storage means for shifting the already stored data one by one one by one, discarding the oldest data, and storing the currently calculated data in the latest data storage area each time data regarding the motor rotation speed is calculated by the means. , whether the latest data calculated this time corresponds to the data corresponding to the center of the size of the plural data stored in the storage means, or whether it is within a predetermined first range with respect to the data. A first determining means for determining, and a second determining means for determining whether or not the difference between the maximum data and the minimum data among the plurality of data stored in the storage means is within a predetermined second range.
The determining means, the first determining means, determines that the latest data corresponds to the data corresponding to the middle of the magnitude or is within a predetermined first range with respect to the data; When it is determined that the difference between the data and the minimum data is within a predetermined second range, the determination means determines whether the motor rotation speed has reached the steady range; The motor control device is characterized in that it includes a control component changing means that relatively increases an integral control component among control signal components that perform feedback control of the motor when it is determined that the motor has reached the control signal component.

Furthermore, a third invention provides a motor control system that performs feedback control of the motor using a control signal including a proportional control component based on a speed difference and an integral control component that integrates the speed difference so that the motor rotation speed becomes equal to the command speed. The apparatus includes a data calculation means for calculating data related to the motor rotation speed at each predetermined timing, a plurality of storage areas capable of storing data related to the motor rotation speed for a predetermined plurality of times in order of newest, and the data calculation means storage means for each time data regarding the motor rotational speed is calculated, sequentially shifting the already stored data one by one, discarding the oldest data, and storing the currently calculated data in the latest data storage area; , whether the latest data calculated this time corresponds to the data corresponding to the middle of the plurality of data stored in the storage means, or whether it is within a predetermined first range for the data. A first determining means determines whether the latest data is within a predetermined second range with respect to predetermined target rotational speed data, and a first determining means determines whether the latest data is large or small. It is determined that the latest data corresponds to data corresponding to the center or is within a predetermined first range with respect to the data, and the latest data is determined to be within a predetermined second range with respect to the target rotation speed data. a determination means for determining that the motor rotation speed has reached the steady range when it is determined that the motor rotation speed has reached the steady range, and a feedback control of the motor when the determination means determines that the motor rotation speed has reached the steady range. A motor control device characterized in that it includes control component changing means for relatively increasing an integral control component among control signal components.

13 Effects> According to the present invention, data regarding the motor rotation speed is calculated at each predetermined timing.

When the data is calculated, the data already stored in the storage means are shifted one by one, the oldest data is discarded, and the data calculated this time is stored in the newest data storage area.

Then, by sorting, data corresponding to the middle of the plurality of data stored in the storage means is obtained, and this data is compared with the latest data calculated this time.

As a result, according to the first invention, if the latest data corresponds to the data corresponding to the middle of the magnitude or is within a predetermined range with respect to the data, it is determined that the motor rotation speed has reached the steady range. , if the motor rotation speed is not within the predetermined range, the motor rotation speed is determined to be in the transient response range.

Then, when it is determined that the motor rotation speed has reached the steady range, the integral control component among the control signal components for feedback controlling the motor is increased to relative ] 4 .

Further, according to the second invention, the latest data calculated this time corresponds to the data corresponding to the middle of the plurality of data stored in the storage means, or a predetermined number is set for the data. 1 range and the difference between the maximum data and the minimum data of the plurality of data stored in the storage means or within a predetermined second range, the motor rotation speed is in the steady range. It is determined that it has been reached.

Then, when it is determined that the motor rotation speed has reached a steady range, the integral control component of the control signal components for feedback controlling the motor is relatively increased.

Furthermore, according to the third invention, the latest data calculated this time corresponds to the data corresponding to the center of the size of the data for a plurality of times stored in the storage means, or a predetermined value is applied to the data. When the motor rotation speed is within the first range and within a predetermined second range with respect to predetermined target rotation speed data, it is determined that the motor rotation speed has reached the steady range.

15 Then, when it is determined that the motor rotation speed has reached the steady range, the integral control component is relatively increased among the control signal components for feedback controlling the motor.

Embodiments Hereinafter, an embodiment of the present invention will be described, taking as an example a case where the present invention is applied to a control circuit of a DC servo motor for driving an optical system (illumination unit and reflection mirror) of a copying machine.

FIG. 1 is a block diagram showing an example of the configuration of a control circuit for a DC servo motor for driving an optical system of a copying machine.

This DC servo motor ]O is of a permanent magnet field type, and is rotationally driven by the driver section 1.
Move 7.

A rotary encoder 12 is connected to the rotating shaft of the servo motor 10. As is already well known, the rotary encoder 12 outputs a speed detection pulse every time the servo motor 10 rotates by a minute angle determined by κ. In this embodiment, the rotary 16 and the encoder 12 have the same period and the same phase.
A-phase and B-phase speed detection pulses (speed detection signals) shifted by 0 degrees are output, and when the servo motor 0 rotates once, each phase, for example, 200 speed detection pulses are output.

Note that instead of the rotary encoder 12, another device that outputs pulses periodically linked to the rotation of the motor 10 may be used.

A speed detection pulse output from the rotary encoder 12 is given to an encoder signal input section 13. The encoder signal human input unit 13 is a circuit for detecting the rotational speed of the servo motor 10 based on the speed detection pulse given from the rotary encoder 12, as will be described in detail later. The output of the encoder signal input section 13 is given to the control section 14.

The control unit 14 is equipped with a CPU, a ROM that stores programs, etc., a RAM that stores necessary data, etc., and performs processing for calculating the difference between the commanded speed and the detected speed, and detecting that the motor rotation speed has reached a steady range. (7) Processing, calculation processing of proportional integral data for controlling the servo motor 10, etc. are performed.

The control section 14 is given an operation command signal and a speed command signal (speed command clock) from a control section (not shown) of the main body of the copying machine. The speed command clock is signal-processed by the speed command signal human power section 15 and then given to the control section 14 .

The proportional-integral control unit 16 is a unit for generating a control signal based on proportional-integral data given from the control section 14. The rotational speed of the servo motor 0 is controlled by a control signal output from the proportional-integral control unit 16.

The driver section 11 determines the rotation direction of the servo motor 10 and performs braking based on a driver section drive signal given from the control section]4.

FIG. 2 is a diagram showing the configuration of the encoder signal input section 13. In this embodiment, the encoder signal input section] 2 has the configuration shown in FIG. 2, and the signal readout by the control section 14 is devised so that 18 accurate speed detection can be performed and the rotational speed of the servo motor 10 can be controlled in a transient manner. It is designed to correctly determine whether it is a response region or a stationary region.

To explain with reference to FIG. 2, encoder signal input section 1
3 includes a rising edge detection circuit 131 that detects the rising edge of the A-phase speed detection pulse sent from the rotary encoder 12, a free-running counter 133 of, for example, a 16-bit configuration that counts up the reference clock, and a rising edge detection circuit 131. A capture register 134 is provided, which uses the rising edge detection output as a capture signal, and uses the capture signal as a trigger to read and hold the count number of the free running counter 133.

The reference clock is a reference clock that serves as a reference for the operation timing of the entire circuit shown in FIG. 1, and when the circuit is composed of a microcomputer, a machine clock is used. Furthermore, if such a reference clock does not exist, a reference clock generation circuit may be provided.

The encoder signal input section 13 further includes an up/down detection section 135 and an up/down counter 13.
6 is provided. The up-down detection unit 135 determines the level of the B-phase rotation pulse when the rise detection output of the A-phase speed detection pulse is given from the rise detection circuit 131, and determines whether the B-phase rotation Hals is at a high level or a low level. This determines whether the servo motor 10 (FIG. 1) is rotating in the normal direction or in the reverse direction. The up/down counter 136 counts up or down the detection output of the rising edge detection circuit 131 based on the determined output of the up/down detection section 135.

Next, the operation of the circuit shown in FIG. 2 will be explained.

The contents of the capture register 134 include the capture signal,
That is, it is updated every time the rising edge of the A-phase speed detection pulse is detected. Further, the up/down counter 136 counts the number of times the rising edge of the speed detection pulse is detected, in other words, the number of speed detection pulses.

Therefore, within a predetermined sampling time Δτ, the 20 up/down counter 136 counts n speed detection pulses, while the free running counter 13
By measuring the number of counts of the reference clock counted at 3, the number of revolutions N can be calculated based on it.

In other words, the rotational speed N [rpm] of the servo motor 10 is determined by the frequency of the reference clock being f [Hz], and the number of A-phase speed detection pulses output from the rotary encoder 12 when the servo motor 10 makes one rotation C [ pprl, the current content of the capture register 131 is CPT, , the previous content of the capture register 131 is CPTo-1, and the number of speed detection pulses is n, it can be calculated as f (1).

Here, in equation (1), since the reference clock frequency f and the number C of speed detection pulses are constants, N,=
nA nACPTl. l CPTn-
+X(2) CX: CPTll CPT. -+.

FIG. 3 shows that the control unit 14 samples the contents of the capture register 134 and the up/down counter 136 at a sampling time Δ.
Rotation speed data N is read every t. At the same time, based on the calculated rotational speed data N7, it is determined whether the motor rotational speed is a transient response region or a steady region, and the control rotational speed N is determined.
The rotation speed detection processing procedure for determining the rotation speed is shown.

The sample time Δt is Δt≧X=CPT. , CPT, 1+... An appropriate time that satisfies (3) is set.

Next, explanation will be given with reference to FIGS. 2 and 3.

22 In the control unit 14, an internal timer sets a constant sampling time Δt
Each time the timer reaches 1 (step S1), the timer resets 1.
(Step S2). Then, the contents of the capture register 134 and up/down counter 136 are read out (step S3).

Next, the count number CPT. of the capture register 134 read this time is read. After the reference clock number X within one sample time Δt is obtained by subtracting the previously stored count number CPT, , of the capture register 134 read last time from , CPTn is stored (step S4).

Also, from the count number UDC of the up-down counter 136 read this time, the count number UDC of the up-down counter 136 read last time which is already stored, .
, the number n of speed detection pulses within one sample time Δt is determined by subtracting UDC. , are stored (step S5).

After that, based on the above-mentioned formula (2), the rotation speed data N (n is a natural number, 1.2, 3, . . . is calculated at each rotation speed data calculation timing) calculated at the current sample timing. ) is calculated (step S6).

Next, in steps 87 to S12, the rotation speed data N obtained in step S6 is obtained. The truth or falsehood of is determined, and the control rotation speed N is determined.

FIG. 4 shows the 2
Types of memories M1 and M2 are shown.

In FIG. 4, the memory M1 is for storing rotation speed data for five times in order from the newest one, and has an area for storing new rotation speed data to an area for storing old rotation speed data. Five storage areas E1 to E5 are provided in this order. That is,
The current (latest) rotation speed data N is in E1. However, the previous rotation speed data N. ffi,, is the rotation speed data N, two times before in E3. -2, is the rotation speed data N.3 times before in E4. -3) is the rotation speed data N from 4 times ago in E5. -4
, are respectively stored.

The memory M2 stores five pieces of 24 rotation speed data N n -N t n - 4. which were stored in the memory M1. It is a memory for sorting, that is, sorting in descending order of size, and has five storage areas E11 to E15.

5 rotational speed data N stored in memory M].

~N,. -4) is sorted, memory M2
For example, five rotation speed data N are stored in area Ell. −
N. . -4, the second largest one is in area E12, the third largest one is in area E13, the fourth largest one is in area E14, and the largest one is in area E12.
The smallest one in 5 is stored respectively. Therefore, when sorting is performed, area E13 contains memory M1.
Among the five rotational speed data stored in , the rotational speed data corresponding to the center of the magnitude is stored.

Note that the memories M1 and M2 are not limited to storage of rotation speed data for five rotations, but may be used for storing any plurality of rotation speed data of three or more, preferably an odd number.

Returning to Figure 3 and continuing the explanation, this rotation speed data N
. Once calculated, the five rotational speed data Nfi to N(I+-41) stored in the memory M1 are shifted (step S7). As a result, the previous data N, is the previous rotational speed. The data N.-1 is stored in area E2 as data N.-1), and the previous data N.-1) is the rotation speed data N two times before. -2, is placed in area E3, and the data N up to that point is -2, which is the rotation speed data N, three times ago. −、、
As a result, data N up to that point is stored in area E4. -3, is 4
Previous rotation speed data N. . -4, and is stored in area E5 as the oldest data N. -4〉
(Rotation speed data from 5 times ago) will no longer be stored.

Furthermore, the latest rotation speed data Nn calculated this time is stored in area E1 (step S8).

Next, the current rotation speed data N. The five speed data N,, to NL,, 4) stored in the memory M1 are sorted, and the five rotation speed data N0 to N, are stored in the areas E11 to E15 of the memory M2. one. , are stored in descending order (step S9). As a result, area E
13 stores five rotational speed data N0 to N (n-41), which corresponds to the center of the number of revolutions 26 to 41 (this will be referred to as "center data N").

Next, current rotation speed data N stored in area E1 of memory M1. is the central data N. stored in area E13 of memory M2. compared to N.n. is N. n
It is determined whether or not it is within a predetermined range (step S1
0). In other words, the latest rotation speed data N calculated this time. It is determined whether or not N is within a predetermined range of data N, n corresponding to the center of the magnitude of the five data for the current time and the past four times as shown by the following equation.

N0 (1-α)≦N. ≦N,. (1+β)...(4
) However, α and β are values that can be used to accurately determine whether the preset motor rotation speed has reached a steady range through experiment or calculation, and when compared with data changes due to noise etc., N,, is Nm. The value is set to a value that allows you to see whether or not there is a larger change than the actual value.

The current rotational speed data Nゎ is shown by the above formula (4).27? If it is not within the range, it is determined that the speed change is relatively large and the motor rotation speed is in the transient response area, the steady range flag is reset, and the latest rotation speed data N, is selected and determined (step S1
1).

On the other hand, the latest rotation speed data N. is within the range shown by equation (4) above, the speed change is relatively small;
It is determined that the motor rotation speed has reached the steady range, the steady range flag is set, and the control rotation speed N is determined by the central data N.
(2) is determined (step S12).

As described above, in the processing of steps 87 to S12, the central data N of the five data of the current time and the past four times is
．． The current rotational speed data is within a certain range of N. , is included, it is determined whether the motor rotation speed is in a transient response region or a steady region. In the transient response region, the latest rotation speed data Nn is used, and in the steady region, the central data N. ，，
are each adopted as the control rotation speed N.

Therefore, in the transient response region, changes in motor speed can be quickly dealt with. In addition, in the steady-state region, even if the speed detection signal changes temporarily due to the influence of instantaneous load fluctuations, noise, etc., the signal Nn affected by such influence is not used, and the central data N is used. is used for control, so stable control can be achieved.

Next, another control that is a further improvement on the control in steps 810 to S12 in FIG. 3 will be described.

FIG. 5 shows steps 810 to S of FIG. 2 is a flowchart showing control contents that can be replaced with 2.

In the case of the control shown in FIG. 3, there are the following concerns.

In other words, if the speed detection signal oscillates as shown by the symbol A in Figure 6A after the control is started until it reaches the steady state, the steady It may be erroneously determined that the limit has been reached.

Referring to FIG. 6B, which shows an enlarged view of the vibration A in FIG. 6A, when the rotational speed data N, is calculated at time tn, the rotation speed data N, is calculated at time tn. ~t4. -4, number of revolutions data N,
,~N,. one. , will be stored 29 in the memory M1. Then, the latest data N.

becomes the data corresponding to the middle of these data. Therefore, if only the determination in step S10 in FIG. 3 is made, it will be erroneously determined that the steady state region has been reached.

Therefore, in this embodiment, in order to prevent the above-mentioned erroneous determination, in addition to the determination in step SIO-1, which corresponds to step SIO in FIG. 3, the determination in step S10-2 is added. .

In step S10-2, the maximum data Nmax of the five data of this time and the past four times is further determined.
(stored in area Ell of memory M2) and minimum data Nmin (stored in area E15 of memory M2) (Nmax - Nmin) is within a predetermined range W. It is determined whether

The difference between the maximum data N max and the minimum data N min (N
max - Nmin) is not within the predetermined range W,
For example, if vibrations such as those shown in Figures 6A and 6B occur in the speed detection signal, 30? It is determined that the rotation speed has not been reached, the steady state flag is reset, and the control rotation speed N is the latest rotation speed data N. (Step S11).

Maximum data N may. and the minimum data Nmin (
If Nmax - Nmin ) is within the predetermined range W, then
The determination that the speed has reached the steady range in step S11J-1 above is determined not to be an erroneous determination due to the vibration F, the steady range flag is set, and the control rotation speed N
is determined to be central data N■ (step S12).

In this way, it is determined whether the motor rotation speed is in the transient response region or the steady region by the two-step discrimination S10-1 and SIO2, so in the transient response region from the start of control until reaching the steady region Even if the speed detection signal oscillates as described above, it will not be erroneously determined that the steady state region has been reached, and the detection of the steady state region will be accurately performed.

In the above control, the determination in step SlO-1 and the determination in step S10-2 may be reversed.

31 FIG. 7 shows step S1 in FIG. Flowchart 1 representing yet another control content that replaces 0 to S12.
It is.

In the case of the control in steps SIO to S12 in FIG. 3, if the rotational speed of the servo motor 0 starts to settle down to a lower speed than the target rotational speed for some reason after the control starts,
There is a risk that it may be erroneously determined that the steady state region has been reached.

Therefore, in this embodiment, in order to prevent the above-mentioned erroneous determination, as shown in FIG.
In addition to the first stage determination of step S10-1 corresponding to O, the second stage determination of step 31.0-2 is performed.

Step S1. In O-2, the latest data N calculated this time. is the target rotational speed data N stored in the memory in advance. The latest data N. is the target rotation speed data N
. It is determined whether or not it falls within a predetermined range of January and February. In other words, the latest rotation speed data N. It is determined whether or not is within the range shown by the following formula.

32 No (1 7) ≦N. ,≦No (1+δ
)... (5) However, γ and δ are predetermined set values.

The latest rotation speed data Nn is the target rotation speed data N.

If it is not within the predetermined range for some reason, the latest rotation speed data N. or target rotation speed data N. In this case, it is determined that the servo motor taco 0 has not reached the steady state, the steady state flag is reset to 1, and the control speed N is set to 1. , latest rotation speed data N. is used (step S11).

On the other hand, the latest rotation speed data N. is the target rotation speed data N. If it is within a predetermined range, it is determined that the rotation speed of the servo motor 10 has reached a steady range, the steady range flag is set, and the control rotation speed N is not affected by noise etc. Central data Nm is used (step S1
2).

In this way, also in this control, step S10-1
and SIO-2, it is determined whether the 33 motor rotation speed is in the transient response region or the steady region, so if the motor rotation speed tries to settle down at a speed lower than the target rotation speed for some reason. However, the detection of reaching the steady state region is performed accurately without erroneously determining that the steady state region has been reached.

In the above control as well, the determination in the [th] stage of step SIO-1 and the determination in the second stage of step S10-2 may be reversed.

Next, the speed command signal input section 15 in FIG. 1 will be explained.

FIG. 8 is a block diagram showing a specific example of the configuration of the speed command signal input section 15. As shown in FIG. In the speed command signal input section 15,
Rising detection circuit 151 for detecting the rising edge of the speed command clock, free running counter 52 for up-counting the reference clock, rising detection circuit]
The rising detection output of 51 is used as a capture signal, and the free running counter 15 uses the capture signal as a trigger.
Capture register 15 that reads and holds the count number of 2
3 and an up counter 154 for up counting the output pulses 34 of the rising edge detection circuit 51.

The free running counter 152 is, for example, a 16-bit counter. This free running counter 152 may also be used in common with the free running counter 133 (see FIG. 2) of the encoder signal input section 13 described above.

The operation of this circuit is as follows.

A speed command clock outputted from a control side microcomputer on the apparatus main body side, for example, a copying machine main body, is applied to a rising edge detection circuit 151, and the rising edge of the speed command clock is detected in the rising edge detection circuit 151. Since the output of the rising edge detection circuit 151 is given to the free running counter 152 as a capture signal, the contents of the capture register 153 are updated in response to the rising edge of the speed command clock. Therefore, the contents of the capture register 153 are read based on a certain rising detection signal, and the contents of the capture register 153 are read based on the next rising detection signal.
By reading the contents of 53 and calculating the difference of 35, it is possible to measure the count number of the free running counter 152 in one period of the speed command clock. In other words, the rotational speed N that is the commanded speed. can be obtained.

Note that in this embodiment, each time the contents of the capture register 153 are updated, the difference between the updated count 1 and the pre-updated count is not calculated, but the detection accuracy is further improved. Therefore, a reading method similar to that of reading the count number of the capture register 53 in the encoder signal input section 13 is used.

That is, the control unit 14 reads the contents of the capture register 153 and the contents of the up counter 154 at every predetermined sampling time Δt, calculates the difference between the count number read this time and the count number read last time in the capture register 153, and calculates the difference between the count number read this time and the count number read last time in the capture register 153. By dividing the difference by the difference between the count number read this time and the count number read last time in the up counter, a more accurate number of reference clocks within one cycle of the speed command clock is obtained.

Next, a method for calculating the proportional integral data output from the control section 14 will be explained.

If the control voltage (proportional control voltage) due to the speed difference ΔN (=NO-N) is e (t), then the cumulative value of the speed difference, that is, the integral control voltage due to the value integrated with the speed difference ΔN is Σe (
t), and the rotation speed N of the servo motor 10 is set to the command speed N. The proportional-integral data voltage VO that should be output to the servo motor 10 in order to follow the equation is expressed by the following equation.

VO−'Ae(t)+BΣe(t) −(
6) However, ASB is a predetermined coefficient, and is B-85 at startup and B-BL (B5 x BL) at steady state.

In other words, in this embodiment, the speed difference ΔN (-N.

Not only the proportional control voltage e (t) by N) but also the control voltage VO corrected by the integral control voltage Σe (t) is output. During steady state 37, the ratio of the integral control voltage is increased. The reason for this is to improve the ability to follow speed fluctuations during steady state.

The proportional control voltage e (t) due to the speed difference ΔN is expressed by the following equation.

? (t)=Ra (GD' ΔNTBL・■+
Io+ 1 375KT Δt K■10KeN -RaGD'・AN+KeN 375I (T Δt +R a (I o +TBL/KT)
- (7) However, Ra: Amateur resistance [Ω] KT: Luk constant [kgm/A] Ke: Induced voltage constant [V/rpm] Io: No-load current [Ako GD2: Moment of inertia due to load and motor [ kg
m2] TBL: Sliding load [kgm] 38.

Note that N is the control rotation speed determined in the process of FIG. 3, FIG. 5, or FIG. 7.

The integral control voltage Σe (t) is the proportional control voltage e (t)
, that is, it is the voltage that accumulates the speed differences up to now.

FIG. 9 is a flowchart showing a procedure for calculating proportional and integral data by the control unit 14.

In the control unit 14, each time the control rotation speed N is determined by the process shown in FIG. 3, for example, based on equation (7),
The proportional control voltage e (t) is calculated and stored (step S31).

Next, in step Sll or S12 of FIG. 3, it is determined whether the state is reset 1 or the steady state flag set (
In step S32), if the steady state flag is reset and the motor rotation speed is in the transient response region, the coefficient B is set to 85 (step 833), and the steady state flag is set and the motor rotation speed has reached the steady state region. In this case, B=BL (step S34), and the control voltage VO=Ae(t)→
−BΣe (t) is calculated (step S35).

39. Therefore, after the start of motor control, the integral control voltage is relatively small during the rise until the steady state is reached, and during the steady state, the integral control voltage is relatively large. In other words, among the control signal components constituting the motor control voltage, the proportional control component is relatively large in the transient response region and relatively small in the steady region.

As a result, the rise time of the motor rotation speed can be shortened, and the speed followability can be improved during steady state.

The present invention is applicable not only to control of the optical system of a copying machine but also to a motor for controlling a reading device of a facsimile machine and other general motor control circuits.

Effects of the Invention Since the present invention is configured as described above, it is possible to reliably detect when the motor rotational speed reaches a steady state from the transient response range, regardless of the magnitude of the load.

In addition, even if the speed detection signal is temporarily adversely affected by instantaneous load fluctuations or noise, the effect will not be reflected in the discrimination results, and it will be possible to accurately detect when the rotation speed has reached the steady range 40. can.

Furthermore, after the motor rotation speed reaches a steady range, it is resistant to noise and the ratio of the integral control component in the control signal is relatively increased, resulting in a stable constant speed that is excellent in following load fluctuations. Control is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of a drive control circuit for a DC servo motor for driving an optical system to which an embodiment of the present invention is applied. FIG. 2 is a circuit block diagram showing the electrical configuration of the encoder input section according to the embodiment of the invention. FIG. 3 is a flowchart showing the rotational speed detection processing procedure in the embodiment of the present invention. FIG. 4 is a diagram showing two memories M1 and M2 used for the steady state reaching detection process. FIG. 5 is a flowchart showing control contents that are a further improvement on the control shown in FIG. 3 and can be replaced with steps SIO to S12 in FIG. FIGS. 6A and 6B are diagrams for explaining problems when a special vibration occurs in the speed detection signal. FIG. 7 is a flowchart showing still another control content that can be replaced with step SIO-31.2 in FIG. 3, which is a further improvement on the control in FIG. FIG. 8 is a block diagram showing an example of the electrical configuration of the speed command signal input section. FIG. 9 is a flowchart showing a procedure for calculating proportional-integral control data by the control unit 14. In the figure, 10...DC servo motor, 11...
Driver section, 12... Rotary encoder, 13...
・Encoder signal input section, ]4...control section, 15...
・Speed command signal input section, 16...proportional integral control unit l., M1, M2...memory.

Claims (1)

[Claims] 1. Motor control that performs feedback control of the motor using a control signal that includes a proportional control component based on the speed difference and an integral control component that integrates the speed difference so that the motor rotation speed becomes equal to the command speed. The apparatus includes: a data calculation means for calculating data regarding the motor rotation speed at each predetermined timing; a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in chronological order, the data calculation means; storage means for shifting the already stored data one by one one by one, discarding the oldest data, and storing the currently calculated data in the latest data storage area, each time data related to the motor rotation speed is calculated; The latest data calculated this time is compared with the data corresponding to the center of the size among the data of multiple times stored in the storage means, and it is determined whether the latest data corresponds to the data corresponding to the center of the size or the data. determination means for determining whether the motor rotation speed has reached a steady range based on whether or not the motor rotation speed is within a predetermined range; and when the determination means determines that the motor rotation speed has reached the steady range. A motor control device comprising: control component changing means for relatively increasing an integral control component among control signal components for feedback controlling a motor. 2. A motor control device that performs feedback control of the motor using a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to the command speed, A data calculation means for calculating data regarding the motor rotation speed at each timing; a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in order of newest; the data calculation means calculates data regarding the motor rotation speed; storage means for sequentially shifting the already stored data one by one and discarding the oldest data each time the data is calculated, and storing the data calculated this time in the latest data storage area; the latest data calculated this time; first determining means for determining whether or not the data corresponds to the data corresponding to the middle of the plurality of data stored in the storage means or is within a predetermined first range with respect to the data; The second determining means determines whether the difference between the maximum data and the minimum data among the plurality of data stored in the storage means is within a predetermined second range, and the first determining means determines whether the latest It is determined that the data corresponds to data corresponding to the center of magnitude or is within a predetermined first range with respect to the data, and the second determination means determines that the difference between the maximum data and the minimum data is within a predetermined first range. a determining means for determining that the motor rotational speed has reached a steady range when it is determined that the motor rotational speed is within the range 2; A motor control device comprising: control component changing means for relatively increasing an integral control component among control signal components. 3. A motor control device that performs feedback control of the motor using a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to the command speed, A data calculation means for calculating data regarding the motor rotation speed at each timing; a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in order of newest; the data calculation means calculates data regarding the motor rotation speed; storage means for sequentially shifting the already stored data one by one and discarding the oldest data each time the data is calculated, and storing the data calculated this time in the latest data storage area; the latest data calculated this time; first determining means for determining whether the data corresponds to the data corresponding to the middle of the plurality of data stored in the storage means or is within a predetermined first range with respect to the data; , a second determination means for determining whether or not the latest data is within a predetermined second range with respect to predetermined target rotational speed data; the first determination means determines that the latest data corresponds to data corresponding to the center of magnitude; or it is determined that the latest data is within a predetermined first range with respect to the target rotation speed data, and the second determination means determines that the latest data is within a predetermined second range with respect to the target rotation speed data. a determination means for determining that the motor rotational speed has reached the steady-state region; and when the determination means determines that the motor rotational speed has reached the steady-state region, integral control A motor control device comprising: control component changing means for relatively increasing the component.