JPH03218286A - Motor controller - Google Patents

Abstract

PURPOSE:To improve constant speed control of a motor by providing means for adding an integrated speed difference control component to a feedback control signal for the motor, when a judgment is made that the rotational speed of motor is reached the steady region, and starting proportional integration control. 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 to 0 and the steady region flag is set, whereas when the rotational speed of motor is reached the steady region, coefficient B is set equal to Bc and the control voltage V0 is calculated according to the formula. Since switching is made to proportional integration control, a stable constant speed control having excellent follow-up performance to variation of load can be 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 (ph3s
e-locked IOOI1) 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.

Problems to be Solved by the Invention> By the way, in the transient response range where the rotational speed of the motor is increased to a steady range, proportional control is generally used to apply a voltage to the motor that is proportional to the speed difference between the target speed and the detected speed. will be held. When the detected speed reaches a predetermined percentage, for example 95%, of the target speed, it is determined that the motor rotational speed has reached a steady range, or the acceleration component is determined based on the previous detected speed and the current detected speed. Based on the calculated value, it was determined that the motor rotation speed had reached a steady range.

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.

In addition, in the method of calculating acceleration and determining whether it has reached a steady range based on the value, even in the transient response range, it may be determined that the acceleration component has become zero 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 Shooting is intense 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 is necessary to control the motor rotation speed so that it does not deviate from the target speed, but with conventional devices, the detected motor rotation speed is affected by noise, etc. There are also disadvantages in that it is difficult to accurately detect the motor rotational speed and it is difficult to control the motor at a constant speed.

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 Problems> A first invention is a motor control device that performs feedback control of a motor using a control signal including a proportional control component based on a speed difference so that the motor rotation speed becomes equal to a command speed. , 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 chronological order; storage means, storage means that sequentially shifts the already stored data one by one nine times, discards the oldest data, and stores the currently calculated data in the latest data storage area each time data related to the data is calculated; Compare the data corresponding to the middle of the size among the multiple data stored in the data and the latest data calculated this time, and check whether the latest data corresponds to the data corresponding to the middle of the size or a specified value for the data. a determination means for determining whether the motor rotation speed has reached the steady range based on whether the motor rotation speed is within the range; and when the determination means determines that the motor rotation speed has reached the steady range; A motor control device characterized in that it includes means for adding an integral control component obtained by integrating a speed difference to a control signal component for feedback controlling the motor, and starting proportional-integral control.

Further, a second invention is a motor control device that performs feedback control of a motor using a control signal including a proportional control component based on a speed difference so that the motor rotation speed becomes equal to a command speed, a data calculation means for calculating data regarding the rotational speed; a plurality of storage areas capable of storing data regarding the motor rotational speed for a predetermined plurality of times in order of newest; the data calculation means calculates data regarding the motor rotational speed; storage means that sequentially shifts the already stored data one by one and discards the oldest data and stores the currently calculated data in the latest data storage area; A first determination means for determining whether the data corresponds to the middle of the plurality of data stored in the storage means, or whether the data falls within a predetermined first range, and the storage means The latest data is determined by the second determining means and the first 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 data is within a predetermined second range. It is determined that the data corresponds to the data corresponding to the center of the 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 second range. When it is determined that the motor rotation speed has reached the steady range, the determining means determines that the motor rotation speed has reached the steady range; This motor control device is characterized in that it includes means for adding an integral control component obtained by integrating a speed difference to a control signal component to start proportional-integral control.

Furthermore, a third invention is a motor control device that performs feedback control of a motor using a control signal including a proportional control component based on a speed difference so that the motor rotation speed becomes equal to a command speed, a data calculation means for calculating data regarding the rotational speed; and a plurality of storage areas capable of storing data regarding the motor rotational speed for a predetermined plurality of times in chronological order, each time the data regarding the motor rotational speed is calculated by the data calculation means. , a storage means that sequentially shifts the already stored data one by one and discards the oldest data, and stores the data calculated this time in the latest data storage area, and the latest data calculated this time is stored in the storage means. A first determining means for determining whether the data corresponds to the data corresponding to the center of the magnitude of the data for the plurality of stored data, and whether or not the data falls within a predetermined first range; is within a predetermined second range with respect to predetermined target rotational speed data, and the first determination means determines whether the latest data corresponds to data corresponding to the center of magnitude or not. When 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, the motor A determining means for determining that the rotational speed has reached the steady range, and an integral obtained by integrating the speed difference into a control signal component for feedback controlling the motor when the determining means determines that the motor rotational speed has reached the steady range. A motor control device characterized in that it includes means for adding a control component and starting proportional-integral control.

Effect> 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 is shifted one by one 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 a steady range, an integral control component obtained by integrating the speed difference is added to a control signal component for feedback controlling the motor, and proportional-integral control is started.

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 value is applied to the data. If the motor rotation speed is within the first range and the difference between the maximum data and the minimum data of the plurality of data stored in the storage means or is 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 rotational speed has reached a steady range, an integral control component obtained by integrating the speed difference is added to a control signal component for feedback controlling the motor, and proportional-integral control is started.

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.

Then, when it is determined that the motor rotation speed has reached a steady range, an integral control component obtained by integrating the speed difference is added to the control signal component for feed-hacking the motor, and proportional-integral control is started.

15 Embodiment An embodiment of the present invention will be described below, taking as an example a case where the present invention is applied to a control circuit of a DC servo motor for driving the 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 10 is of a permanent magnet field type, and is rotationally driven by a driver section 11.
Move 7.

A rotary encoder 12 is connected to the rotating shaft of the servo motor 0. As already known, the rotary encoder 12 outputs a speed detection pulse every time the servo motor 10 rotates by a predetermined minute angle. The rotary encoder 12 of this embodiment outputs A-phase and B-phase speed detection pulses (speed detection signals) that have the same period and are out of phase by 90 degrees, and the servo motor 10
By rotating, each phase, for example, 20016 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 servo motor 10 may be used.

The speed detection pulse output from the low-resolution encoder 12 is given to the encoder signal input section 13. The encoder signal input section 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] 3 is given to the control section 14.

The control unit 14 is equipped with a CPU, a ROM that stores programs, a RAM that stores necessary data, etc., and calculates the difference between the commanded speed and the detected speed, and calculates the motor rotation speed until it reaches a steady range. Detection processing, calculation processing of proportional and integral data for controlling the servo motor 10, etc. are performed.

The control unit 14 is given an operation command signal and a speed command signal (speed 17 degree command clock) from a control unit (not shown) of the main body of the copying machine. The speed command clock is
Speed command signal input section] 5, the signal is processed and then the control section 1
given to 4.

The proportional-integral control unit] 6 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 6.

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 manual section 13. As shown in FIG. In this embodiment, the encoder signal input section 12 has the configuration shown in FIG. 2, and the signal readout by the control section 14 is devised, so that accurate speed detection is possible and the rotational speed of the servo motor 10 is within the transient response range. It is designed to be able to correctly determine whether it is in the stationary region.

To explain with reference to FIG. 2, the encoder signal 18 input section 13 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, and a rising edge detection circuit 131 that up-counts the reference clock. For example, a 16-bit free running counter 133 and a rising edge detection output of the rising edge detection circuit 131 are used as capture signals, and a capture register 134 is provided which uses the captured 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 136. The up/down detector 135 determines the level of the B19 phase rotation pulse when the rising edge detection output of the A phase speed detection pulse is given from the rise detection circuit 131, and determines whether the B phase rotation pulse is at a high level or a low level. By servo motor 10
(Fig. 1) is used to determine whether the rotation is normal or reverse. 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, if n speed detection pulses are counted by the up/down counter 136 within a predetermined sampling time Δτ, and the number of reference clocks counted by the free running counter 133 during that period is measured, then
Based on this, the rotation speed 20 N can be calculated.

In other words, the rotational speed N [rpm] of the servo motor 10 is the frequency of the reference clock f [Hz], and the speed detection pulse number of the A phase output from the rotary encoder 12 when the servo motor 10 rotates once. C [ppr, the contents of the current capture register 131 are CPT. , the contents of the previous capture register 131 are converted to CPT. If l and the number of speed detection pulses are n, it can be calculated as f (1).

Here, in equation (1), since the reference clock frequency f and the speed detection pulse number C are constants, NfnA nA (2) CPT. 1 CPT, X 21 However, A:-! -X60CX: CPT, -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. , and the calculated rotational speed data N. Based on this, it is determined whether the motor rotation speed is in the transient response region or the steady region, and the control rotation speed N is determined.
The rotation speed detection processing procedure for determining the rotation speed is shown.

The sampling time Δt is set to an appropriate time that satisfies the following: Δt≧X=CPTll−CPTn−+ − (3).

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

In the control unit 14, an internal timer keeps a constant sampling time Δt.
Each time the timer reaches (step S1), the timer is reset (step S2). And capture register 1
34 and the up/down counter 22. The contents of the counter 136 are read (step S3).

Next, the count number CPT. of the capture register 134 read this time is changed to the count number CPT. ,−
By subtracting +, the number of basic clocks X7>j within one sample time Δt is determined, and then CPTo is stored (step S4).

Also, from the count number UDC,, of the up-down counter 136 read this time, the count number U D of the up-down counter 136 read last time which is already stored is calculated.
After the number n of speed detection pulses within one sample time Δt is obtained by subtracting C n-1, the 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 for each rotation speed data calculation timing) calculated at the current sample timing.
, 3, and so on. ) is obtained (step S6).

Next, in steps 87 to S12, it is determined whether the rotation speed data N obtained in step s6 is true or false, and the control rotation speed N is determined.

FIG. 4 shows steps 87-81. Two types of memories M1 and M2 used for processing No. 2 are shown.

In FIG. 4, the memory M1 is for storing rotational speed data for five times in order from the newest one,
5 in order from the area for storing new rotation speed data to the area for storing old rotation speed data.
Storage areas E] to E5 are provided. That is, E1 is the current (latest) rotational speed data Nfi, and E2 is the previous rotational speed data N. -1, is in E3 the rotation speed data N(n-21) two times ago, E4 is the rotation speed data Nin-31 three times ago, and E5 is the rotation speed data N(n-21) the fourth time ago.
41 are stored respectively.

The memory M2 contains five rotational speed data N, -N, stored in the memory M1. -4, in order of size, and has five storage areas E]-1 to E15.

Five rotation speed data N,, 24 to N stored in memory M1 (if I1-41 is sorted, memory M
For example, the largest of the five rotation speed data Nゎ~N(n-4) or the second
The third largest one is in area E13, the fourth largest one is in area E14, and the fourth largest one is in area E13.
The smallest one in 15 is stored respectively. Therefore, when sorting is performed, area E13 has memory M
Among the five rotation speed data stored in No. 1, the rotation 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
, , are calculated, the five rotational speed data N7 to N-4 stored in the memory M1 are shifted (step S7). As a result, the previous data N. , is stored in area E2 as the previous rotation speed data N t,l-1+,
The previous data NLn-11 was 25? Previous rotation speed data N (area E3 as I1-21)
, the previous data N (++-2+ is the rotation speed data N 3 times before (I+-31 is stored in area E4, the previous data N. -3, is the rotation speed data N 4 times ago. -4 , is stored in area E5 as the oldest data, N.-4, (rotation speed data from five times ago) is no longer stored.

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

Next, the current rotation speed data N. Five speed data N stored in memory M1 including. -N,.

4) is sorted and the areas E11 to M2 of memory M2 are sorted.
E15 contains five rotation speed data N. -N. -4, but
They are stored in descending order (step S9). As a result, area E13 contains five rotational speed data Nfi to N(n-
41, the rotation speed data corresponding to the center of the magnitude (this is
The central data N■) will be stored.

Next, current rotation speed data N stored in area E1 of memory M1. But is Eri 26 of memory M2? It is compared with the central data N■ stored in E13,
N. is N. It is determined whether or not it is within a predetermined range (step S10). In other words, the latest rotation speed data N calculated this time. It is determined whether or not Nm is within a predetermined range of data Nm 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.

Nm (1-α)≦N1≦NIN (1+β)...(
4) However, α and β are values that can accurately determine whether the motor rotation speed has reached a preset motor rotation speed or a steady range by experiment or calculation, and when compared with data changes due to noise etc., N. is set to a value that allows it to be determined whether or not Nm is changing more greatly than Nm.

Range 1 where the current rotational speed data N0 is shown by the above formula (4)
If the second month has not entered, the speed change is relatively large,
It is determined that the motor rotation speed is in the transient response region, the steady state flag is reset, and the latest rotation speed data N is used as the control rotation speed N. Selection 27 is determined (step S11).

On the other hand, if the latest rotational speed data N0 is within the range shown by the above formula (4), 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.
．． (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 N is within a certain range. By determining whether or not the motor rotation speed is in the transient response region or the steady region, it is determined whether the motor rotation speed is in the transient response region or the steady region. In the transient response region, the latest rotation speed data N, 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, even if the speed detection signal changes temporarily due to the influence of instantaneous load fluctuations, noise, etc., the signal N affected by such influence. is not used, and the central data N. ,, or control 28, stable control can be performed.

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

FIG. 5 is a flowchart showing control contents that can be replaced with step SIO-312 in FIG.

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 vibration A in FIG. 6A, rotation speed data N is obtained at time point 1n.

is calculated, the time j n ””' j Ln-4)
Rotation speed data N for 5 times. -N (I1-41 will be stored in the memory M1. Then, the latest data N.

is 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 SIO-2, the maximum data Nmax (stored in area Ell of memory M2) and the minimum data Nmin (stored in area E15 of memory M2) of the five data for the current and past four times are further added. ) is within a predetermined range W or not.

If the difference between the maximum data NIIIaX and the minimum data Nmin (Nmax - Nmin) is not within the predetermined range W, vibrations as shown in FIGS. 6A and 6B, for example, will simply occur in the speed detection signal. It is determined that the steady state region 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).

If the difference between the maximum data Nmax and the minimum data Nmin is 30 (Nmax - Nmin) or is within the predetermined range W, it is determined that the speed has reached the steady range in step S10-1. It is determined that there was no misjudgment due to etc., the steady region flag is set, and the control rotation speed N
is the central data N. 1 (step S12).

Thus, step 5 1. 0-1 and Sh
Since it is determined whether the motor rotation speed is in a transient response region or a steady state region through two-stage discrimination called o2, the speed detection signal has the above-mentioned effect in the transient response region from the start of control until reaching the steady state region. Even if vibration occurs, it will not be erroneously determined that the steady state region has been reached, and detection of reaching the steady state region will be performed accurately.

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

FIG. 7 is a flowchart 1 representing yet another control content that can be replaced with steps SIO to S12 in FIG.

In the case of the control in steps SIO to S12 in FIG. 3, if the rotational speed of the servo motor 10 settles down to a speed lower than the target rotational speed for some reason after the 31 control starts, it is determined that the steady state region has been reached. There is a risk of misjudgment.

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 SIO-1 corresponding to O, the second stage determination of step SIO-2 is performed.

In step S10-2, the latest data N calculated this time
, , is the L1 standard rotation 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 is within a predetermined range. In other words, it is determined whether the latest rotational speed data Nn is within the range expressed by the following equation.

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

32 The latest rotation speed data Nfi 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 the standard rotation speed data N. Since the rotation speed is settling down to a lower number than The rotation speed data N0 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 zarpo 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 N. is used (step S
12).

In this way, in this control, step S10-
1 and S 1 0-2, it is determined whether the motor rotation speed is in the transient response region or the steady region.
Even if the motor rotational speed attempts to settle down at a speed lower than the target rotational speed for some reason, it is not erroneously determined that the steady-state region has been reached, and detection of reaching the steady-state region is accurately performed.

In the above control as well, step 3 1. The first stage determination of step SIO-1 and the second stage determination of step SIO-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,
A rising edge detection circuit 151 for detecting the rising edge of the speed command clock, a free running counter for up-counting the base clock 52, a rising edge detection circuit 15
] is used as a capture signal, and the free running counter 15 uses the capture signal as 1.
Capture register 1 that reads and holds the count 1 of 2
53 and an up-counter 154 for up-counting the output pulses of the rising edge detection circuit 151.

The free running counter 152 is, for example, a 16-bit counter. This free running counter 152 may 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.
53 and find the difference, the free running counter 152 in one cycle of the speed command clock
The number of counts can be measured. In other words, the rotational speed N that is the commanded speed. can be obtained.

35 In this embodiment, each time the contents of the capture register 153 are updated, the method is not to obtain the count number that is the difference between the count number after the update and the count 1.number before the update, but to further improve the detection accuracy. In order to do this, a reading method similar to that of reading the count number of the capture register 153 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 reference evening lock number 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 (ratio 36 example control voltage) due to the speed difference ΔN (-N.-N) is e (t), the cumulative value of the speed difference is
In other words, the integral control voltage based on the value integrated by the speed difference ΔN is Σ
e (t), and the rotational speed N of the servo motor 10 is the commanded 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 at the time of rising,
B=0, and during steady state, B=Bo.

In other words, in this embodiment, the motor rotation speed is
In the transient response region), speed control is performed only by the proportional control voltage e (t) due to the speed difference ΔN (-N.-N), but when the motor rotation speed reaches the steady region, not only the proportional control voltage Speed control is performed using a control voltage VO (proportional-integral control voltage) which is corrected by an integral control voltage Σe (t). The reason for this is to improve the ability to follow speed fluctuations during steady state.

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

? (t)=Ra (GD2 ・-!-u+Io+1-1375KT Δt K ■ 10Ke
N-RaGD2. AN+K8N 375KT Δt 10R a (I o +TBL/KT) −
(7) However, Ra: amateur resistance [Ω KT: torque constant [kg++/A] Ke: induced voltage constant E V /rpmE o: no-load current [A GD': moment of inertia due to load and motor [kg
m2 TBI: sliding load [kgm].

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

38 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, the state of the steady region flag reset or set in step Sll or S12 in FIG. 3 is determined (step S32), and if the steady region flag is reset and the motor rotation speed is in the transient response region, the coefficient B-0 is determined. (Step 833), and if the steady state flag is set and the motor rotation speed has reached the steady state, B=BC is set (Step S34), and the control voltage V O = A e (
t)→−BΣe(1) is calculated (step S35)
.

Therefore, when the motor rotation speed rises to a steady state after the start of motor control, the rise time of the motor rotational speed can be shortened by proportional control, and at the same time, during steady state, the followability of the speed can be improved by proportional-integral control.

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 the steady range 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 is possible to accurately detect when the rotation speed has reached a steady state. .

Furthermore, after the motor rotation speed reaches a steady range, it is resistant to noise and the control switches to proportional-integral control.
Stable constant speed control with excellent followability to load fluctuations 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 special vibrations occur in the speed detection signal. FIG. 7 is a flowchart showing still another control content that is a further improvement on the control shown in FIG. 3 and can replace steps 810 to S12 in FIG. FIG. 8 is a block diagram showing an example of the electrical configuration of the speed command signal manual section. FIG. 9 is a flowchart showing a procedure for calculating proportional-integral control data by the control unit 14. 41 In the figure, 10...DC servo motor, 11...
Driver section, 12... Rotary encoder, 13...
・Encoder signal human power section, 14...control section, 15...
-Speed command signal input section, 16...proportional integral control unit, M1, M2...memory. 42 N Fig. 6A Fig. 6 R Fig. JP-A-3-218286 (14) To Fig. 7 N)≦≦

Claims (1)

[Claims] 1. A motor control device that performs feedback control of a motor using a control signal including a proportional control component based on a speed difference so that the motor rotation speed becomes equal to a command speed, the motor control device controlling the motor at predetermined timings. A data calculating means for calculating data regarding the rotational speed, having a plurality of storage areas capable of storing data regarding the motor rotational speed for a predetermined plurality of times in order of newest, each time the data regarding the motor rotational speed is calculated by the data calculating means. storage means that sequentially shifts the already stored data one by one, discards the oldest data, and stores the data calculated this time in the latest data storage area; and multiple data stored in the storage means. Compare the data corresponding to the middle of the size and the latest data calculated this time, and based on whether the latest data corresponds to the data corresponding to the middle of the size or whether it is within a predetermined range for the data. a determination means for determining whether the motor rotation speed has reached the steady range; and when the determination means determines that the motor rotation speed has reached the steady range, A motor control device comprising: means for adding an integral control component obtained by integrating a difference to start proportional-integral control. 2. A motor control device that performs feedback control of the motor using a control signal including a proportional control component based on the speed difference so that the motor rotation speed becomes equal to the command speed, and calculates data regarding the motor rotation speed at each predetermined timing. data calculation means for calculating the motor rotation speed, the data calculation means having a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in chronological order, and each time data regarding the motor rotation speed is calculated by the data calculation means, storage means for sequentially shifting the data one by one, discarding the oldest data, and storing the data calculated this time in the latest data storage area; the latest data calculated this time being stored in the storage means for multiple times; A first determining means for determining whether the data corresponds to the data corresponding to the center of the data or whether it is within a predetermined first range with respect to the data; a plurality of times of data stored in the storage means; The second determining means determines whether the difference between the maximum data and the minimum data is within a predetermined second range, and the first determining means determines that the latest data corresponds to the data corresponding to the middle of the magnitude. or when it is determined that the data is within a predetermined first range, and the second determining means determines that the difference between the maximum data and the minimum data is within a predetermined second range, A determining means for determining whether the motor rotational speed has reached a steady range; and an integral control in which a speed difference is integrated into a control signal component for feedback controlling the motor when the determining means determines that the motor rotational speed has reached a steady range. A motor control device comprising: means for adding a component and starting proportional-integral control. 3. A motor control device that performs feedback control of the motor using a control signal including a proportional control component based on the speed difference so that the motor rotation speed becomes equal to the command speed, and calculates data regarding the motor rotation speed at each predetermined timing. data calculation means for calculating the motor rotation speed, the data calculation means having a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in chronological order, and each time data regarding the motor rotation speed is calculated by the data calculation means, storage means for sequentially shifting the data one by one, discarding the oldest data, and storing the data calculated this time in the latest data storage area; the latest data calculated this time being stored in the storage means for multiple times; a first determining means for determining whether the latest data corresponds to data corresponding to the center of the magnitude of the data or is within a predetermined first range with respect to the data; The first determining means determines whether the latest data corresponds to the data corresponding to the center of the magnitude, or if the latest data falls within a predetermined second range. 1 range, and when the second determining means determines that the latest data is within a predetermined second range with respect to the target rotation speed data, the motor rotation speed has reached a steady range. When the motor rotation speed is determined to have reached a steady range by the determination means for determining that the motor rotation speed has reached a steady range, an integral control component obtained by integrating the speed difference is added to the control signal component for feedback controlling the motor, and proportional-integral control is performed. A motor control device comprising: means for starting.