JPH03218284A - Motor controller - Google Patents

Abstract

PURPOSE:To perform constant speed control of a motor by taking out a newest data when the rotational speed of motor is not reached the steady region, judging the validity of the newest data when the rotational speed of motor is reached the steady region, and taking out the newest data if it is valid whereas taking out a data corresponding to the central value if the newest data is not valid. CONSTITUTION:A timer is reset for every sample time ( t) at a control section 14. Content is then read out from a capture register 134 and an up-down counter 136. Then, a count (CPTn-1) is subtracted from a count (CPTn) in order to determine a reference clock within one sample time t, and the count CPTn is stored. A count (UDCn-1) is then subtracted from a count (UDCn) in order to determine a speed detection pulse (n) within one sample time t, and the count UDCn is stored. Thereafter, the data of the number of revolution is obtained and the validity thereof is judged thus determining the number of revolution for control.

Description

[Detailed Description of the Invention] <Industrial Application Field> 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.

BACKGROUND OF THE INVENTION PLL (phas
e-locked loop) control methods are known.

In addition, PWM (pulse width modulation) related to the applicant's earlier application
There is a control method using signals. This control method obtains the PWMrW signal based on a control component proportional to the speed difference between the target speed and the detected speed and a control component proportional to the phase difference between the target speed signal and the detected speed signal, and controls the motor speed. It is something to control.

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 that applies a voltage proportional to the speed difference between the target speed and the detected speed to the motor is generally performed. It will be done. Then, the detected speed is a predetermined percentage of the target speed.
For example, when the motor rotation speed reaches within 95%, it is determined that the motor rotation speed has reached the steady range, or the acceleration component is calculated based on the previous detected speed and the current detected speed, and the rotation speed is determined based on that value. It was determined that the speed had reached a steady range.

However, in the method of determining that the motor rotation speed has reached a steady range by reaching a predetermined percentage (for example, 95%) of the detected speed or the target speed, for example, if the load is larger than the set value, the motor rotation speed is lower than the target speed. The speed also stabilizes at a low speed (for example, 90% of the target speed),
However, there were cases in which it was not determined that the steady state region had been reached, no matter how long it took.

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.

[7] As in the former case, if it is determined that the motor rotational speed has not reached the steady range, PLL control or the cannot enter into control, and even if P
Even if L L control or PWM signal control is started, overshoot is severe 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. 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 rotational speed reaches the steady-state region from the transient response region. 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 motor can be controlled at a constant speed. The purpose of this invention is to provide a motor control device.

Means for Solving the Problems> A first invention is a motor control device that performs feedback control of a motor so that the motor rotation speed becomes equal to a command speed, and which transmits data regarding the motor rotation speed at predetermined timings. The data calculation means has a plurality of storage areas capable of storing data related to 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, A storage means that sequentially shifts the data one by one, discards the oldest data, and stores the data calculated this time in the latest data storage area. The data corresponding to the center is compared with the latest data calculated this time, and the motor rotation is determined based on whether the latest data corresponds to the data corresponding to the center of magnitude or whether it is within a predetermined range for the data. A determining means for determining whether the speed has reached the steady range, and when the determining means determines that the motor rotation speed has not reached the steady range, extracting the latest data as speed data in the unsteady range. , When it is determined that the motor rotation speed has reached the steady range, it is further determined whether the latest data is appropriate, and when the latest data is appropriate, the latest data is used, and when the latest data is inappropriate, it is A motor control device characterized in that it includes speed data determining means for extracting data corresponding to the speed data as speed data in a steady region.

Further, a second invention is a motor control device that performs feedback control of a motor so that the motor rotation speed becomes equal to a command speed, the motor control device comprising: data calculation means for calculating data regarding the motor rotation speed at each predetermined timing; It has 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 data, and each time data related to the motor rotation speed is calculated by the data calculation means, data related to the motor rotation speed is stored. A storage means for sequentially shifting the data one by one and discarding up to 8 data, and storing the currently calculated data in the latest data storage area; A first determination means for determining whether the data corresponds to the data corresponding to the middle of the magnitude of the data for the batch or whether it is within a predetermined first range for the data; The second determining means and first determining means determine whether the difference between the maximum data and the minimum data of the data is within a predetermined second range, and the latest data corresponds to data corresponding to the center of magnitude. or when the data is determined to be 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 the steady range; and a determining means for determining whether the motor rotational speed has reached the steady range. When it is determined that the motor rotation speed has reached the steady range, it is further determined whether the latest data is appropriate, and if the latest data is appropriate, the latest data is used, and if the latest data is inappropriate, the large/small center A motor control device characterized in that it includes speed data determining means for extracting data corresponding to the speed data as speed data in a steady region.

Furthermore, a third invention is a motor control device that performs feedback control of a motor so that the motor rotation speed becomes equal to a command speed, the motor control device comprising: data calculation means for calculating data regarding the motor rotation speed at each predetermined timing; It has a plurality of storage areas capable of storing data related to the rotational speed for a predetermined number of times in order of newest, and each time the data calculation means calculates data related to the motor rotational speed, the already stored data is sequentially updated one by one. A storage means for discarding the oldest data and storing the data calculated this time in the latest data storage area, and the latest data calculated this time is among the data of multiple times stored in the storage means. corresponds to the data corresponding to the center of the size of
A first determining means for determining whether or not the data is within a range, a second determining means for determining whether the data is the latest data or a predetermined second range with respect to predetermined target rotation speed data, and a first determining device. The means determines that the latest data corresponds to 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 latest data corresponds to the target rotation speed data. On the other hand, when it is determined that the motor rotation speed is within a predetermined second range, the determination means determines that the motor rotation speed has reached the steady range, and the determination means determines that the motor rotation speed has not reached the steady range. When it is determined that the motor rotation speed has reached the steady region, the latest data is extracted as the speed data in the unsteady region, and when it is determined that the motor rotation speed has reached the steady region, the suitability of the latest data is further determined. Latest] 4 1-Event is the latest data or unsuitable j; When JJ is present, the data corresponds to the center of the magnitude and small. Speed data determination f stage to take out the speed decimal and L in the steady region. It is a device.

According to this definition, data relating to the motor rotational speed can be calculated at a certain time.

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

Then, by sorting, the data corresponding to the middle of the size among the multiple data stored in the memory 19 is found, and this data is compared with the latest data retrieved this time.

Conclusion According to the first invention, if the latest data corresponds to the data that corresponds to the center 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 it is determined that the seek rotation speed is not within the predetermined range, the seek rotation speed is determined to be in the transient response region.

Then, the electric current determined to be in the transient response region of the motor rotational speed is handled as the speed data to be used for the latest data or engineering control, and the motor rotational speed is determined to be in the constant response region. Furthermore, the suitability of the latest data is determined, and if the latest data is appropriate, the latest data is selected, and if the latest data is inappropriate, the data corresponding to the center of the size or the motor is selected. Speed data to be used for control and l,2
is removed.

Further, according to the second invention, the latest data calculated this time corresponds to data corresponding to the middle of the plurality of data stored in the recording means, or a predetermined value is applied to the data. When the motor rotation speed is within the first range and the difference between the maximum data and the minimum data among the plurality of data stored in the storage means is within the predetermined second range, the motor rotation speed is in the steady range. It is determined that it has reached {7.

Then, when it is determined that the motor rotation speed has not reached the steady range, the latest data or speed data to be used for motor control is extracted, and it is determined that the motor 1-6 rotation speed has reached the steady range. If the latest data is appropriate, the latest data is used, and if the latest data is inappropriate, the data corresponding to the center of the magnitude is used as the speed data to be used for motor control. [7 and removed.

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

When it is determined that the motor rotation speed has not reached the steady range, the latest data is retrieved as the speed data to be used for motor control. , Roughly, the suitability of the latest data is judged, and the latest data is suitable 1; when it is IJ, the latest data is inappropriate; when it is JJ, the data corresponding to the center of human resources] 7. It is extracted as speed data to be used for.

Embodiments Hereinafter, as an embodiment of the present invention, a case where the present invention is applied to a control circuit of a DC servo motor for driving an optical system (illumination unit 1 and reflection mirror) of a copying machine will be described.

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. In this control circuit, PWM (pulse width motful) is used as the voltage applied to the DC servo motor.
tion) signal is used.

This DC servo motor ]O is of a permanent magnet field type 2 and is rotationally driven by the driver section 1 to move the optical system 17 .

Servo motor】Rotary encoder on the rotation axis of 0）2
are connected. As already known, the rotary encoder 2 outputs speed detection pulses when the motor 10 rotates by a predetermined minute angle.

In this embodiment, the rotary operator 18 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 10 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 servo 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 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 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 calculation processing of the difference between the command speed and the detected speed, the speed command signal and the speed detection signal, etc. (19) Phase difference calculation processing, motor rotational speed reaching steady state detection processing, PWM data calculation processing 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 a speed command signal input section 15 and then supplied to the control section 14.

The PWM units 1 and 16 receive P from the control section 14.
PW of pulse width (output duty) according to WM data
This is the unit that generates the M signal. The rotational speed of the servo motor 10 is controlled by a PWM signal output from the PWM 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 14 .

FIG. 2 is a diagram showing the configuration of the encoder signal input section 13. In this embodiment, the encoder signal 20 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 does not respond to transient response. It is designed so that it can be correctly determined whether it is a region or a stationary region.

To explain with reference to FIG. 2, encoder signal input section 1
3 includes a rising edge detecting circuit 131 that detects the rising edge of the A-phase speed detection pulse sent from the low-res encoder 12, a free running counter of, for example, a 16-bit configuration that counts up the reference clock 33, and a rising edge detecting circuit. A capture register 134 is provided, which uses the rise detection output of the free running counter 131 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 if 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 21 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 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,
Depending on whether the B-phase rotation pulse is at a high level or a low level, it is determined whether the servo motor 10 (FIG. 1) is rotating in the forward 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 22 by 1.

Therefore, if the up-down counter 136 counts n speed detection pulses within a predetermined sample time ΔT, and during that time the free running counter 133 counts the reference clock to 1, then The rotation speed N can be calculated by

In other words, the rotation 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 by one revolution of the servo motor 10 being C [ppr]. , the current content of the capture register 131 is CPT, the previous content of the capture register 131 is CPTn-1, and the number of speed detection pulses is n, then it can be calculated as f (1) 23 .

Here, in equation (1), since the reference clock frequency f and the speed detection pulse number C are constants, N= nA
=nACPT, -CPTn. X (2) However, A: Engineering x 60 0 X: CPTII CPT, -+.

In FIG. 3, the control unit]4 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 sample time Δt is Δt≧X=CPT, −CPT. , - An appropriate time that satisfies (3) is set.

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

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

Next, from the count number CPT of the capture register 134 read this time, the count number CPT of the capture register 134 read last time which is already stored is calculated, -
After the reference clock number X within one sample time Δt is determined by subtracting 1, CPTn is stored (step S4).

Also, from the count 1/number UDC of the up/down counter 136 read this time, the already stored count number U D of the up/down counter 136 read last time.
After the number n of speed detection pulses within one sample time Δt is determined by subtracting C n-1, UDCn is stored (step S5).

After that, based on the above formula (2), the rotation speed data N (n is a natural number, calculated at the current 25 sample timing,
．． It increases by 2, 3, etc. ) is obtained (step S6).

Next, in steps S7 to S12, the rotation speed data N obtained in step S6 is obtained. is determined to be true, 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,
E1 has the current (latest) rotation speed data Nゎ, E2 has the previous rotation speed data N (n-11), E3 has the two previous rotation speed data N (n-21, or E4 has the third previous rotation speed data). Rotation speed data N
《. -3》 is the rotation speed data N, 4 times ago in E5. one.
, 26 are stored, respectively.

Memory M2 contains five rotational speed data N stored in memory M1. -Nun-4+ is a memory for sorting, that is, arranging in descending order of size, and has five storage areas Ell to E15.

Five rotation speed data N stored in memory M1.

~N (if II-41 is sorted, memory M
2 area E 1. 1, for example, five rotation speed data N. -NL. , -4), the largest one is in area E
12, the 3rd largest in area E13, and the 4th largest in area E14. Area E1. The smallest one in 5 is stored respectively. Therefore, when sorting is performed, area E1
3 stores rotation speed data corresponding to the center of the five rotation speed data stored in the memory M].

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.

27 Returning to Figure 3 and continuing the explanation, the current rotation speed data N
．． , is calculated, the five rotation speed data N. stored in the memory M1 are calculated. , ~N (n-41) is shifted (step S7). As a result, the previous data Nn is transferred to area E2 as the previous rotation speed data N,.
The previous data N (n - 1 1 is the rotation speed data N, . . . . . . . 2, and is stored in area E3 as the data N.-2, the rotation speed data N, . . . . . . . . . . ．．
3, to area E4, and the previous data N. . ，，
is the rotation speed data N from four times ago. -4, is stored in area E5 as the oldest data N-4
, (rotation speed data from five 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 N0 to N4 stored in the memory M1 including
rotation speed data N. -N,. -4, are recorded in descending order (Stepsop S9) 28? As a result, area E13 contains five rotation speed data N.
. -N,. -4, rotation speed data corresponding to the center of magnitude (this will be referred to as "center data Nm") is stored.

Next, current rotation speed data N stored in area E1 of memory M1. is compared with central data Nm stored in area E13 of memory M2, and it is determined whether N is within a predetermined range of N (step S10).
. In other words, the latest rotation speed data N calculated this time. It is determined whether or not is within a predetermined range of N pieces of data corresponding to the center of the size of the five pieces of data for the current and past four times as shown by the following equation.

N,, (1-α)≦N. ,≦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 by experiment or calculation, and when compared with data changes due to noise etc., N, is 29 ? ing.

This rotation speed data N. is not within the range shown by the above equation (4), it is determined that the speed change is relatively large and the motor rotation speed is in the transient response region, the steady region flag is reset, and the control rotation The latest rotation speed data N is the number N. is selected and determined (step S11).

On the other hand, if the latest rotational speed data Nfi is within the range shown by the above equation (4), it is determined that the speed change is relatively small and the motor rotational speed has reached the steady region, and the steady region flag is flagged. is set, and the control rotation speed N is determined to be 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 of m. By determining whether or not the motor rotation speed is in the transient response region or the steady region, the latest rotation speed data Nfi is used in the transient response region, and the central data Nffi is used in the steady region.
However, the control rotation speed N can be set to 30, respectively.

Therefore, in the transient response region, it is possible to quickly respond to changes in the motor speed, and in the constant response region, instantaneous load changes and
Due to the influence of the noise 1-. Even in this case, the signal N1, which has been affected by the noise, is used for control, and the central data N1 is used for control.

In addition, in the illustrated embodiment, it is determined that the motor rotational speed has reached the steady range in S12.
In one case, the control rotation speed N is unconditionally the central data N.

, or 1', which adds the following discrimination control, is preferable.

First, when it is determined that the motor rotational speed has reached the steady range, after the steady range flag is set, the latest data N is further updated. The purpose of this is to make it possible to determine whether or not the property is properly accounted for. This determination of suitability means that the latest data N,
This means determining whether the control rotation speed N in the steady range is appropriate or inappropriate. This determination is made based on, for example, whether the latest data N1 satisfies this equation (4) when the values rχ and β in equation (4) above are made smaller. be able to.

In this way, when it is determined that the Tanabata rotation speed has reached the steady region, it is further determined whether the latest data Nn is appropriate (7) If the latest data N1 is appropriate, the latest data N If . is used as the control quadrature number N, there is an advantage that the followability of the motor rotational speed control in the steady region becomes better.

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 replace steps 810 to S12 in FIG. 3.

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

In other words, if the speed detection signal in Fig. 6A occurs after the control starts until it reaches the fixed division range? When vibrations such as those shown in item A occur, it may be mistakenly determined that the steady state region has been reached, even though the steady state region has not been reached.

See Figure 6B, which shows vibration A in Figure 6A enlarged. To explain in detail, the rotation speed data N at time 1n.

is launched, the time tn =t,. -4, rotation speed data N for the number of times. -N(n-41) will be stored in the memory M1. Then, the latest data N.

Of these data, the data corresponds to the middle in terms of size. Therefore, the determination made in step S10 in FIG. 3 will result in an erroneous determination that the steady state region j7 has been reached.

Therefore, in this embodiment, the above-mentioned misjudgment is prevented +l.
To avoid this, follow step S1 in FIG. In addition to the determination of step SIO-1 corresponding to O, step 'l;'S1
．． 0-2 discrimination is added.

Step Si. In 0-2, the maximum data Nmax of the 5 data of this time and the past 4 times is
(stored in area E of memory M2 - 1) and minimum data Nmjn (area E of memory M2
It is stored in 15. ) (Nmax −Nmi
It is determined whether or not n ) is within a predetermined range W.

The difference between the maximum data NmaX and the minimum data Nmjn is 3'3? Nmax - Nmin ) is not within the predetermined range W, it is determined that the speed detection signal has vibrations such as those shown in FIGS. 6A and 6B and has not reached a steady state, and the steady state The area flag is reset to 1, and the control rotation speed N is the latest rotation speed data N. (Step S11).

Difference between maximum data N maX and minimum data N min (
If Nmax - Nmin ) is within the predetermined range W, then
Above step S1. The determination that the speed has reached the steady range at O-1 is determined not to be a misjudgment due to vibration etc., the steady range flag is set to 1, and the control rotation speed N is determined to be the 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 in the two steps S10-1 and S102. In this case, even if the speed detection signal oscillates as described above, it will not be erroneously determined that the steady range has been reached, and the detection of reaching the constant '51ζ range will be performed accurately.

34 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 showing still another control content that can replace 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 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. 7, step S1 in FIG.
In addition to the first stage determination of step SIO-1 corresponding to 0, the second stage determination of step S10-2 is performed.

In step 510-2, the latest data N calculated this time
. is the 1'' standard rotation speed data N stored in the memory in advance. The latest data Nn is compared with the target rotation speed data N.
. It is determined whether 35 is within a predetermined range of . In other words, the latest rotation speed data N,
, is within the range shown by the following formula.

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

Latest rotation speed data N. is the target rotation speed data N.

If it is not within the predetermined range for some reason, the latest rotation speed data N. is the target rotation speed data N. Therefore, in such a case, it is determined that the servo motor 10 has not reached the steady state region, the steady state flag is reset, and the control speed N
The latest rotational speed data N, , is used for this (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 determined to be free from the influence of noise etc. No central de 36? The data N■ is used (step S12).

In this way, also 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, so if the motor rotation speed has tried to settle down at a speed lower than the target rotation speed for some reason. Even in the case where the stationary area has been reached, the detection of reaching the stationary area is performed accurately without erroneously determining that the stationary area has been reached.

Also in the above control, the first stage determination in step SIO-1 and the second stage determination in step S10-2 may be reversed.

Step S1 in FIGS. 5 and 7 explained above
2, similarly to the previously described embodiment, when it is determined that the motor rotation speed has reached the steady range, the control rotation speed N is not unconditionally determined to be the central data N■, but the latest data N. It is determined whether or not the data is suitable as control data in the steady state region, and if it is, the latest data N is used.

is the control rotation speed N, and the central data N. is used only when it is inappropriate. It is preferable to set it to 37 so that the rotation speed N is determined as the control rotation speed N.

Next, the speed command signal input section]5 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 152 for counting up the reference clock, and a rising edge detection circuit 15
The rising detection output of 1 is used as a capture signal, and the free running counter 152 uses the capture signal as a trigger.
A capture register 153 that reads and holds the count number of
And an up counter 154 for up counting the output pulses of the rising edge detection circuit 151 is provided.

The free running counter] 52 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 manual section 13 described above.

38 The operation of this circuit is as follows.

A speed command clock output from a control microcomputer on the apparatus main body side, for example, a copying machine main body, is applied to a rising edge detection circuit 151, which detects the rising edge of the speed command clock. 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, if the contents of the capture register 153 are read out based on a certain rising edge detection signal, the contents of the capture register 153 are read out based on the next rising edge detection signal, and the difference is found, the free speed in one cycle of the speed command clock can be calculated. running counter 1
52 counts can be measured. 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 count number after the update and the count number before the update is calculated. 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 zamble 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 clock number within one cycle of the speed command clock is obtained.

FIG. 9 shows a procedure for calculating the phase difference between the speed command clock and the speed detection pulse by the control section 14.

First, the rising edge detection circuit 13 of the encoder signal human input section 13
1 detects the rising edge of the speed detection pulse (step S21), the count value of the running counter 133 of the freer 40 is read and the value is stored as the phase comparison value PDT (step S21).
22). Since the free running counter 133 starts counting the reference clock from the start of motor control, the phase comparison value PDT. The value corresponds to the time from the start of motor control to the time when the current pulse rise is detected.

Next, the phase reference value PP I, is calculated and stored (step 823).

PPI,=PPI,fi. ,,+SPD...(6
) Here, P P I +, -+,: Previously stored phase reference value S
PD: Reference clock number for one period of speed command clock (SPD is a fixed value).

However, PPI. . -,． Since the initial value of is zero,
"The first time after starting the motor control in step S21 of Section 2]]
When the rising edge of the speed detection pulse is detected, the corresponding phase reference value PPI becomes SPD41.

Thereafter, the phase difference P H D T is calculated using the following equation and stored (step S24).

SPD Then, the above processing is repeated. That is, every time the rising edge of the speed detection pulse is detected (step S21)
, reading the count value of the free running counter 133 and the phase comparison value PDT. Update (step S22)
, phase reference value PPI. calculation and update (step 82
3) and calculation of phase difference PHDT (step S24)
is repeated 2 times.

After the start of motor control, when the second rise of the speed detection pulse is detected in step S21, the phase reference value PP is calculated in step 323. The value of is 2SP
D, and when the third rising edge of the speed detection pulse is detected, it becomes 3SPD. That is, step 323
Phase reference value PPI calculated by . The value is the product of the total number of speed detection pulses outputted from the start of motor control to the 42nd time of speed detection pulses and SPD.

Since SPD is a fixed value depending on the period of the speed command clock, the phase reference value PPI calculated in step 823
．． is a value corresponding to the time from the start of motor control to the time of the rise of the speed command clock corresponding to the speed detection pulse whose rise was detected this time.

Then, a value (phase comparison value PD
T, ) and the value (phase reference value PPI,) corresponding to the time from the start of motor control to the rising point of the speed command clock corresponding to the speed detection pulse whose rising edge was detected this time is calculated as the speed command clock. Value according to the period of (SPD)
The phase difference PHDT is calculated by dividing by . Therefore, even if the phase difference between the speed command clock and the speed detection pulse is one cycle or more of the speed command clock,
The phase difference PHDT is accurately detected.

43 Next, a method of calculating PWM data output from the control unit 14 will be explained.

The rotation speed N of servo motor] 0 is the command speed N.

PW that should be output to the servo motor 10 in order to follow
The M data voltage VO is expressed by the following equation, where 1 is the control voltage (proportional control voltage) due to the speed difference ΔN (=NN), and V2 is the control voltage due to the phase difference PHDT.

VO=V]→-V2 (8) In other words, in this embodiment, the proportional control voltage ■1 due to the speed difference ΔN (=NoN) is corrected by the control voltage V2 due to the phase difference P H DT. The reason for this is that proportional control based only on the speed difference ΔN does not provide good followability to load fluctuations.

Therefore, in order to improve followability, in this embodiment, the proportional control voltage V] due to the speed difference ΔN (=N.-N) is corrected by the control voltage V2 due to the phase difference PHDT.

The proportional control voltage V1 based on the speed difference ΔN is expressed by the following equation.

44 ■1=Ra{ GD2 ・憇+IO+ }T[lL 375KT Δt KTtenK e N ,,. RaGD” , AN1KeN 375K, Δt +Ra (IO+TBL/KT) − (
9) However, Ra: Amateur resistance [Ω] K7: Luk constant [kgm/A] Ke: Induced voltage constant [V/rpm] Io: No-load current [A] GD2: Moment of inertia due to load and motor [kgm]
2 pieces TRL: sliding load [kgm].

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

The control voltage V2 due to the phase difference PHDT is determined as follows, assuming that the predetermined maximum value of the control voltage V2 is V2max.

45 (A) At the time of rise from the start of speed control to the steady region (a) When the phase difference is smaller than 3 cycles (-3<PHDT<+3) V2= (V2max /3) ・PHDT...
(10) (b) When the phase difference is 3 cycles or more and the phase of the speed detection signal is ahead of the phase of the speed command signal (PHDT≦-3) V2=-V2max ・= (1 1
) (C) When the phase difference is 3 cycles or more and the phase of the speed detection signal lags the phase of the speed command signal (PHDT≧+3) V2=+V2max −(1.2) Therefore, the phase difference PHDT and The relationship with the control voltage v2 is as shown in FIG.

(B) In the case of steady region (a) When the phase difference is smaller than the period 46 (-1<PHDT<+1) V2=V2max # PHDT -=
(1 3) (b) When the phase difference is -12 for one cycle or more and the position i[+ of the speed detection signal is ahead of the phase of the speed command signal (PHDT≦-1) V2=-V2max - ( 14)(
c) When the phase difference is one cycle or more and is delayed from the phase of the speed detection signal or the phase of the speed command signal (PHDT≧+1) V2 = 10V2max - (] 5) Therefore, the phase difference PHDT and the control The relationship with voltage V2 is as shown in FIG.

FIG. 12 is a flowchart showing a procedure for calculating PWM data by the control unit 14.

In the control section]4, each time the control rotation speed N is determined by, for example, the process shown in FIG. 3), the proportional control voltage V1 is calculated based on equation (9) (step S31).

47 Next, the state of the reset 1 or steady state flag set in step Sll or S12 in FIG. 3 is determined (
Step S32), if the steady-state region flag is reset and the motor rotation speed is in the transient response region, the above equations (10) to (1
2) is calculated based on (step 833).

On the other hand, if the steady state flag is set and the motor rotation speed has reached the steady state (A, -1 2 equations (13) to (1)
2 is calculated based on 5) (step S34).

Then, v1 obtained in step S31 and step S
33 or V2 obtained in S34 is added to calculate the control voltage VO (step S35).

Therefore, after the start of motor control, the control voltage due to the phase difference is relatively low during the rise until the steady state is reached, and during the steady state, the control voltage due to the phase difference becomes extremely high. 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, it is possible to prevent the motor rotational speed from increasing to a speed considerably higher than the command speed when standing or turning, and to improve speed followability during steady state, thereby preventing tax adjustment of the servo motor 10. I can do it.

Note that the method of changing the proportion of the proportional control component among the motor control signal components is not limited to the above-mentioned embodiment.
You can do it like this:

``When determining the control voltage V2 based on the phase difference based on the two equations (10) to (15), the flag is set to the reset state.''
At the time of lily, V2max is set to a relatively small predetermined value S, and in the steady region where the flag is set, V2max
is set to a predetermined value L that is relatively large.

Alternatively, when determining the control voltage V2 based on the position difference, p is obtained by combining -L equations (13) to (15) both in the rise time and in the steady state. 2, at the rising edge of the flag reset state, set V2max to il
V2max is set to a relatively large predetermined value L in the steady region where the flag is set.

Furthermore, the control voltage (2) based on the phase difference is always calculated in the same way, for example, based on the -1 set (13) to (15), and the proportional control component (1) itself is increased or decreased depending on whether it is rising or in the steady state. May be adopted.

FIG. 13 is a block diagram showing a specific example of the configuration of the PWM unit 1.]6, and FIG.
3 is a timing chart for explaining the operation of FIG.

The PWM unit 16 includes a set signal generation section 161,
PWM data register 16'. 2 and down counter 1
-63 and RS flip-flop]64.

The set signal generator 161 generates a set signal at regular intervals. This set signal generation section] 61
is composed of, for example, a ring counter, and is configured to generate a set 1 signal every time a certain number of reference crosslocks are counted.

The PWM data register 162 is for holding PWM data given from the control section 14 or 50. The PWM data given from the control unit 14 is voltage data obtained by the above-mentioned equation (8). That is, the proportional control voltage v1 of equation (9) is converted to the phase difference data PH.
This is the voltage vO corrected by the control voltage V2 by the DT. This PWM data is used to determine the duty of the PWM output signal output from the PWM units 1 and 16.

The down counter 163 counts down every time a PWM reference clock (in this embodiment, the PWM reference clock is a reference clock used in the encoder signal input section 13 and the speed command signal input section 15) is provided. When the set number is counted, a reset signal is output.

The operation of the PWM unit 16 is as follows.

When the set 1 signal is output from the set signal generating section 161, the contents of the PWM data register 162, that is, the PWM data given from the control section 14, are transferred to the down counter 1.
63, and the flip-flop 164 is set by the set signal. Therefore, the output of flip-flop 164, that is, PW
The M signal becomes high level.

Next, the down counter 163 counts down based on the PWM reference clock, and when the set count value reaches "0", a reset signal is given to the flip-flop 164. Therefore, the output of flip-flop 164 is inverted to low level.

As a result, the PWM unit 16 determines the duty based on the value held in the PWM data register 162, that is, the voltage data calculated by equation (8), and derives the PWM signal.

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.

Further, the present invention can also be applied when calculating an applied voltage using a signal other than a PWM signal.

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

Furthermore, after the motor rotational speed reaches a steady range, it is resistant to noise and stable constant speed control is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of a drive control circuit for an optical system drive DC servo motor 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. 533. 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 step S10-312 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 the phase difference detection processing procedure in the embodiment of the present invention. Figure 10 shows the phase difference PHDT used when speed rises.
3 is a graph showing the relationship between control voltage v2 and control voltage v2. FIG. 11 is a graph showing the relationship between the control voltage V2 and the phase difference PHDT used in steady state. FIG. 12 is a flowchart showing a procedure for calculating PWM data by the control unit 14. 54 FIG. 13 is a block diagram showing a specific electrical configuration of the PWM unit. FIG. 14 is a timing chart showing the operation of the PWM unit. In the figure, 10...DC servo motor, 11...
Driver section, 12... Rotary encoder, 13...
・Encoder signal input section, 14...control section, 15...
・Speed command signal human power section, ]-6...PWM unit,
M], M2...indicates memory. 55th fourth niece (1st)

Claims (1)

[Claims] 1. A motor control device that performs feedback control of a motor so that the motor rotation speed becomes equal to a command speed, comprising: data calculation means for calculating data regarding the motor rotation speed at each predetermined timing; It has a plurality of storage areas capable of storing data related to the rotational speed for a predetermined number of times in order of newest, and each time the data calculation means calculates data related to the motor rotational speed, the already stored data is sequentially updated one by one. A storage means for discarding the oldest data and storing the data calculated this time in the latest data storage area; 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, it is determined whether the motor rotation speed has reached a steady range. When the determination means determines whether or not the motor rotation speed has reached the steady region, the latest data is taken out as speed data in the unsteady region, and the motor rotation speed reaches the steady region. If it is determined that the latest data is appropriate, the latest data is determined to be appropriate, and if the latest data is inappropriate, the data corresponding to the center of the magnitude is used as the speed data in the steady region. A motor control device comprising: speed data determining means for extracting speed data. 2. A motor control device that performs feedback control of the motor so that the motor rotation speed becomes equal to the command speed, the data calculation means calculating data regarding the motor rotation speed at each predetermined timing; It has a plurality of storage areas that can store a predetermined number 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 to the oldest one. Storage means for discarding the data and storing the data calculated this time in the latest data storage area, the latest data calculated this time corresponds to the data corresponding to the center of the size of the data for multiple times stored in the storage means first determining means for determining whether or not the data is within a predetermined first range; , a second determining means for determining whether or not the latest data falls within a predetermined second range; a determination that the motor rotation speed has reached a steady range when it is determined that the difference between the maximum data and the minimum data is within a predetermined second range 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 by the means and the determining means that the motor rotation speed has not reached the steady region, the latest data is retrieved as speed data in the unsteady region, and when it is determined that the motor rotation speed has reached the steady region. , furthermore, a speed data determining means that determines the suitability of the latest data and takes out the latest data when the latest data is appropriate, and when the latest data is inappropriate, takes out data corresponding to the center of magnitude as speed data in the steady region. A motor control device comprising: 3. A motor control device that performs feedback control of the motor so that the motor rotation speed becomes equal to the command speed, the data calculation means calculating data regarding the motor rotation speed at each predetermined timing; It has a plurality of storage areas that can store a predetermined number 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 to the oldest one. A storage means for discarding the data and storing the data calculated this time in the latest data storage area; a first determining means for determining whether the latest data is within a predetermined first range with respect to the predetermined target rotational speed data; The first determining means determines whether the latest data corresponds to the data corresponding to the center of magnitude or is within a predetermined first range with respect to the data, and 2. When the determining means determines that the latest data is within a predetermined second range with respect to the target rotational speed data, the determining means determines that the motor rotational speed has reached a steady range; When it is determined that the motor rotation speed has not reached the steady range, the latest data is extracted as speed data in the unsteady range, and when it is determined that the motor rotation speed has reached the steady range, the suitability of the latest data is further checked. The present invention is characterized by comprising a speed data determining means for determining and extracting the latest data when the latest data is appropriate, and extracting data corresponding to the center of magnitude when the latest data is inappropriate as the speed data in the steady region. Motor control device.