JPH03218281A - Motor controller - Google Patents

Abstract

PURPOSE:To improve constant speed control of a motor by providing means for relatively increasing the phase difference control component in a feedback control signal of the motor when a judgment is made that the rotational speed of motor is reached to a steady region. CONSTITUTION:When the rising detecting circuit 131 at an encoder signal input section detects rising edge of a speed detection pulse, count in a free running counter 133 is read in then it is subjected to phase comparison and stored. Then, a phase reference is calculated and stored. Thereafter, phase difference is calculated and stored. The operation is repeated. Since the ratio of the phase difference control component due to a control signal increases relatively, 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.

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

Furthermore, there is a control method using a PWM (pulse width modulation) signal, which is related to an earlier application by the present applicant. This control method obtains a PWM 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. There is also a method to control motor speed.

Each of the control methods described in 1 and 1 is fully effective in constant speed control and 17 after the motor reaches a steady state region.

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

However, in the method of determining that the motor rotation speed has reached a steady range by reaching a predetermined percentage (for example, 95%) of the detected speed or the target speed, for example, if the load is greater than the set value, the target speed is There have been cases where the speed has stabilized at a speed lower than the target speed (for example, 90% of the target speed), and no matter how long it takes, it is not determined that the steady state region has been reached.

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

If it is determined that the rotational speed of the motor has not reached the steady range as in the former case, control using PWM signals is entered based on PLL control or the proportional component and phase difference component devised by the applicant. And even if PLL
Even if 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 accurately detect when the motor rotation speed changes from a transient response range to a steady range.

In addition, 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 rotation speed, and it is difficult to control the motor at a constant speed.

Therefore, this invention was made to eliminate each of the two drawbacks, and it is possible to accurately detect when the motor rotation speed has reached the steady range from the transient response area, and the motor rotation speed can be After reaching the steady state, 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 effectively. The purpose of the present invention is to provide a motor control device as described above.

Means for Solving the Problem> The first invention provides a proportional control component based on a speed difference and a phase difference based on a phase difference between a command signal and a detection signal so that the motor rotation speed becomes equal to the command speed. A motor control device that performs feedback control of a motor using a control signal including a control component, wherein the data calculation means calculates data regarding the motor rotation speed at each predetermined timing, and the data calculation means calculates data regarding the motor rotation speed for a predetermined number of times. It has multiple storage areas that can be stored in sequence, 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, the oldest data is discarded, and the current calculation is performed. A storage means for storing the calculated data in the latest data storage area, compares the latest data calculated this time with data corresponding to the middle of the data of multiple times stored in the storage means, and determines whether the latest data is large or small. a determination means for determining whether the motor rotational speed has reached a steady range based on whether the data corresponds to the center or is within a predetermined range with respect to the data; , comprising control component changing means for relatively increasing a phase difference control component among control signal components for feedback controlling the motor when it is determined that the motor rotational speed has reached a steady range. It is a motor control device.

Further, the second invention operates the motor using a control signal including a proportional control component based on the speed difference and a phase difference control component based on the phase difference between the command signal and the detection signal so that the motor rotation speed becomes equal to the command speed. A motor control device that performs feedback control, and includes a data calculation means that calculates data related to motor rotation speed at each predetermined timing, and a plurality of storage areas that can store data related to the motor rotation speed for a predetermined plurality of times in chronological order. 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, the oldest data is discarded, and the currently calculated data is placed in the latest data storage area. The storage means to be stored, whether the latest data calculated this time corresponds to the data corresponding to the middle of the size among the multiple data stored in the storage means, or within a predetermined first range for the data. A first determining means for determining whether or not the data exists, and determining whether the difference between the maximum data and the minimum data among the plurality of data stored in the storage means is within a predetermined second range. The second determining means and the first determining means determine that the latest data corresponds to the data corresponding to the center of the magnitude or are within a predetermined first range with respect to the data, and the second determining means The difference between the maximum data and the minimum data is the predetermined second
a determining means for determining that the motor rotational speed has reached the steady range when it is determined that the motor rotational speed is within the range; and a feedback control of 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 a control component changing means for relatively increasing a phase difference control component among control signal components.

Furthermore, the third invention controls the motor using a control signal including a proportional control component based on the speed difference and a phase difference control component based on the phase difference between the command signal and the detection signal so that the motor rotation speed becomes equal to the command speed. 12 A motor control device that performs feedback control, comprising a data calculation means that calculates data related to the motor rotation speed at each predetermined timing, and a plurality of storage areas that can store data related to the motor rotation speed for a predetermined plurality of times in order of newest. 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, the oldest data is discarded, and the currently calculated data is stored in the latest data storage area. The latest data calculated this time corresponds to the data corresponding to the middle of the data of multiple times stored in the storage means, or is within a predetermined first range for the data. The first determining means determines whether the latest data is within a predetermined second range with respect to the predetermined target rotational speed data, and the first determining means , it is determined that the latest 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 latest data is determined to be the target rotation speed data of 13 degrees by the second determination means. and determining means for determining that the motor rotational speed has reached a steady range when it is determined that the motor rotational speed is within a predetermined second range; The motor control device is characterized in that it includes a control component changing means for relatively increasing a phase difference control component among control signal components that perform feedback control of the motor.

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

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

As a result, according to the first invention, if the latest data corresponds to the data corresponding to 14 large and small centers or is within a predetermined range with respect to the data, it is determined that the motor rotation speed has reached the steady range. If the motor rotation speed is not within the predetermined range, the motor rotation speed is determined to be in the transient response range.

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

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

Then, when it is determined that the motor rotational speed has reached the steady range, the phase difference control component is relatively increased by 15 among the control signal components for controlling the feed/<ts>k of the motor.

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 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 the steady range, the phase difference control component is relatively increased among the control signal components for feedback controlling the motor.

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

FIG. 1 is a block diagram showing an example of the configuration of a control circuit for a DC servo motor for driving an optical system of a copying machine. In this control circuit, PWM (pulse width) is used as the voltage applied to the DC servo motor 16.
modulation) signal is used.

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 installed on the rotating shaft of the servo motor 10.
are connected. As is already well known, the rotary encoder 2 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 when the servo motor 10 rotates once, each For example, 200 speed detection pulses are output.

Note that instead of the low-return encoder 12, another device that outputs pulses periodically linked to the rotation of the servomotor 10 may be used.

A speed detection pulse output from the low-resolution encoder 12 is applied 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. , a process for detecting that the motor rotation speed has reached a steady range, a process for calculating PWM data for controlling the servo motor 10, etc. are performed.

The control section 14 is given an operation command signal and a speed command signal (speed command clock) from a control section (not shown) of the main body of the copying machine. The speed command clock is subjected to signal processing by a speed command signal input section 15 and then provided to the control section 14.

PWM unit] 6 is a PWM unit given from the control unit 14.
This is a unit for generating a PWM signal with a pulse width (output duty: 18) according to M data.

The rotation speed of the servo motor 10 is controlled by the PWM signal output from the PWM units 1 and 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 input section ] 2 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 [0] is transient. It is designed to correctly determine whether it is a response region or a stationary region.

To explain with reference to FIG. 2, encoder signal input section 1
3 includes a rising edge detection circuit 131 that detects the rising edge of the A-phase speed detection pulse sent from the rotary encoder 12, a 19-bit free running counter 133 that up-counts the reference clock, and a 19-bit free-running counter 133 that up-counts the reference clock. The rise detection output of the circuit 131 is used as a capture signal, and the free running counter 1 is activated using the capture signal as a trigger.
A capture register] 34 for reading and holding a count 1 of 33 is provided.

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 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. Up/down counter 20 The counter 136 is for up-counting or down-counting the detection output of the rising edge detection circuit 131 based on the determination output of the up/down detection section 135.

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

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

Therefore, within a predetermined sampling time ΔT, the up/down counter 136 counts n speed detection pulses, and during that time the free running counter 133 counts the reference clock count 1. The rotation speed N can be calculated by

In other words, the rotation speed N [rpm] of the servo motor 10 is the frequency of the reference clock f [Hz], and the number of A-phase speed detection pulses output from the rotary encoder 21 and coder 12 when the servo motor 0 rotates once. C
[apr], the contents of the current capture register 131 are CPT, , the contents of the previous capture register 131 are CPT, , and the number of speed detection pulses is n, then 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, N= nA CPTo -CPT, = nA X (2) However, A: -! -X60CX: CPTI1 -CPT,

22 In FIG.
Especially read out the rotation speed data N. In addition to calculating the rotation 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 be an appropriate time that satisfies the following: Δt≧X=CPT, CPTo−+ − (3).

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

The control unit 14 uses an internal timer to set a constant sampling time Δt.
When the timer is reached (step S1), a timer is set (step S2). And capture register 1
34 and the contents of the up/down counter 136 are read out (step S3).

Next, by subtracting the previously stored count number CPT, -+ of the capture register 134 read last time from the count I/number CPT, of the capture register 134 read this time, the value within one sample time Δt is calculated. After the reference clock number X is determined, CPT
, is recorded (step S4).

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

After that, based on the above formula (2), the rotation speed data N (n is a natural number, 1.2, 3
,... and so on. ) is found (step S
6).

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 the 2
Types of memories M1 and M2 are shown.

24 In FIG. 4, the memory M1 is for storing rotation speed data for five times in order from the newest one, and is used to store old rotation speed data from an area for storing new rotation speed data. Five storage areas E1 to E5 are provided in order from area to area. That is,
The current (latest) rotation speed data N is in E1. However, E2 contains the previous rotation speed data N,. -1, is the rotation speed data N.2 times before in E3. . -2, is the rotation speed data N from 3 times ago in E4
(n-31 is the rotation speed data Nun-4 from 4 times ago to E5.
1 is memorized one by one.

The memory M2 is a memory for sorting the five rotational speed data N n -N (n 4 ) stored in the memory M1, that is, arranging them in descending order of size, and has five storage areas E]. 1 to E]-5.

Five rotation speed data Nn to N(
. -4), for example, five rotation speed data N0 to N, are stored in area Ell of memory M2.

-4. The largest one is in area E12, the second largest one is in area E13, the 325th largest one is in area E]. The fourth largest one is stored in area E15, and the smallest one is stored in area E15. Therefore, when sorting is performed, the area E1B stores rotation speed data corresponding to the center of the five rotation speed data stored in the memory M].

Note that the memories M] 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
When n is calculated, the five rotational speed data N.n stored in the memory M1 are calculated. , ~NLn-41 are shifted (step S7). As a result, the previous data N. is the previous rotation speed data N. -1) in area E2, and the previous data N. -1) is the rotation speed data N, two times before. −
2, in area E3, the previous data NIR-
2) is the rotation speed data N, three times before. 3. Area E as
4, the previous data N,. 3. is the rotation speed data N.4 times before. . -4)26? The previous data N, which is the oldest data, is stored in area E5. -4, (rotation speed data from 5 times ago) is no longer stored.

Furthermore, the latest rotation speed data N0 calculated this time is stored in area E1 (step S8).

Next, five speed data Nn-N(.

4. are sorted and the areas E11~ of memory M2 are sorted.
E15 contains five rotation speed data N. -N〈. -4> are stored in descending order (step S9). As a result,
Area E1B contains five rotation speed data N. -N,. −
4. Rotation speed data corresponding to the center of magnitude (this is referred to as "
Central data N. ) is stored.

Next, current rotation speed data N stored in area E1 of memory M1. is compared with central data N,,l stored in area E1B of memory M2, and No.
It is determined whether or not it is within a predetermined range (step S1
0). In other words, the latest rotation speed data N0 calculated this time is expressed by the following formula. Then, it is determined whether the data N■ corresponding to the middle of the five data of the past four times is within a predetermined range.

N,, (1-α)≦N0≦NIN(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. It is set to a value that allows you to know whether or not there is a larger change with respect to n.

This rotation speed data N. is not within the range shown by equation (4) above, 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 selected and determined (step S11).

On the other hand, the latest rotation speed data N. is within the range shown by equation (4) above, the speed change is relatively small;
When the motor rotation speed reaches the steady range?28? It is determined that the steady state flag is set, and the control rotation speed N is determined to be the central data Nm (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. Each of these is 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, n is used for control, so 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 shows steps SIO to S12 and 29 in FIG. 3 is a flowchart showing replaceable control contents.

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, time t. The rotation speed data N.

is calculated, the time tn ”” j (5 of n-4+
Rotation speed data N for each batch. -Nun-41 will be stored in 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, steps S]. In addition to the determination of step SIO-1, which corresponds to step 30, the determination of step SIO-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.

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

Difference between maximum data N maX and minimum data N min (
If Nmax - Nmin ) is within the predetermined range W, then
The determination that the speed has reached the steady range in step SIO-1 above is determined not to be a misjudgment due to vibration etc., the steady range flag is set, and the control rotation speed B1 rotation speed N is determined to be the central data Nm. (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-step discrimination step SIO-1 and S10-2, so the transient response from the start of control until reaching the steady region is Even if the above-mentioned vibration occurs in the speed detection signal in the range, it will not be erroneously determined that the steady range has been reached, and the detection of reaching the steady range 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 showing still another control content that can be replaced with step SIO-812 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.

32 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
n is target rotation speed data N stored in 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, the latest rotation speed data N. , is within the range shown by the following formula.

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

Latest rotation speed data Nfi or 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. 33 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 revolution number N is set to the latest value. 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 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. The central data Nm that does not exist is used (step S
12).

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

In the above control as well, the first stage determination in step SIO-1 and the second stage determination in step SIO-2 may be reversed.

34 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 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
Further, an up counter 154 for up counting the output pulses of the rising edge detection circuit 151 is provided.

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

The operation of this circuit is as follows.

35 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. The output of the rising edge detection circuit 151 is given to the free running counter 152 as a capture signal, so the contents of the capture register 153 are determined by the rising edge of the speed command clock.
It will be updated in response to the second request. Therefore, if the contents of the capture register 153 are read out based on a certain rising detection signal, the contents of the capture register 153 are read out based on the next rising detection signal, and the difference is found, the free running counter 1 in one period of the speed command clock can be calculated.
A count of 52 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 updated count 1 and the pre-updated count is not calculated, but the detection accuracy is further improved36. 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 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 unit 14.

First, the rising edge detection circuit of the encoder signal input section 13]3
1, when the rising edge of the speed detection pulse is detected (step S21), the free running counter]3
The count value of 37 is read, and that value is the phase comparison value PDT.37. It is stored together (step S22). 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 PPI, is calculated and stored (step 823).

PPI,,=PPI,. -,,10SPD...(6
) Here, PPI-1,: Previously stored phase reference value SPD
: Number of reference clocks per cycle of speed command clock (S
PD is a fixed value. ).

However, since the initial value of P P I +,, -++ is zero, in step S21, the first
Phase reference value PP corresponding to when the rising edge of the second speed detection pulse is detected I. The value of is SPD.

38 After this, the phase difference PHDT is calculated by the following equation and stored (step S24).

SPD Then, the following two processes are repeated. In other words, only the rising edge of the speed detection pulse is detected (the steno knob S21
), reading the count value of the free running counter 133 and phase comparison value PDT. update (step S22
), phase reference value PPI. Calculate and update (Step 8
23) and calculation of the phase difference P H D T (step S24) are repeatedly performed.

After the start of motor control, when the rising edge of the second speed detection pulse is detected in step S21, step 8
The value of the phase reference value PPI calculated in step 23 is 2SPD, and when only the third rising speed detection pulse is detected, it becomes 3SPD. In other words, the value of the phase reference value PPIn calculated in step 323 is the product of the total number of speed detection pulses output from the start of motor control to the rising edge of the 39th speed detection pulse and SPD.

Since SPD is a fixed value depending on the period of the speed command clock, the phase reference value PP calculated in step 823
1n 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 PPIo) 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 difference between the value (phase reference value PPIo) of the speed command clock Value according to cycle (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.

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

The rotation speed N of the servo motor 10 is the command speed N.

PW that should be output to [servo motor] 0 to follow
The M data voltage VO is expressed by the following equation, where V1 is the control voltage (proportional control voltage) due to the speed difference ΔN (=N-N), and 2 is the control voltage due to the phase difference PHDT.

VO=V1+V2 - (8) In other words, in this embodiment, the proportional control voltage V1 due to the speed difference ΔN (=NoN) is changed to the control voltage V2 due to the phase difference PHDT.
It is corrected with. The reason for this is that proportional control based only on the speed difference ΔN does not have good followability to load fluctuations.

Therefore, in order to improve followability, in this embodiment, the proportional control voltage V1 based on the speed difference ΔN (-No N) is corrected by the control voltage v2 based on the phase difference PHDT.

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

4]? 1=Ra f GD'ΔN' TB
L・■4− 1 o + 1 375KT Δt K■? -Ke
N = RaGD”, AN+KeN 3 7 5 K T Δt + Ra (I o +TBL/ I(T)
- (9) However, Ra: Amateur resistance [ΩK]: Torque constant [kgm/A] Ke: Induced voltage constant [V/rpm] ■o: No-load current [A] GD2: Moment of inertia due to load and motor [kg
m2] TBl is the same induced load [ktml].

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, where V2max is the maximum value of the predetermined control voltage (2).

(A) During the rise from the start of speed control to the steady state (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 (11)
(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−+V2I1ax・−(1 2) Therefore, the phase difference PHDT and the control The relationship with voltage v2 is
The relationship shown in FIG. 10 is obtained.

(B) In the case of steady region 43 (a) When the phase difference is smaller than one cycle (-1<PHDT<+1) V2=V2max −PHDT −(1B)(
b) When the phase difference is one cycle or more and the phase of the speed detection signal is ahead of the phase of the speed command signal (PHDT≦-1) V 2 = − V 2 max ・
...(14)(e) When the phase difference is one cycle or more and the phase of the speed detection signal lags the phase of the speed command signal (PHDT≧+1) V2=+V2max +++ (1
5) Therefore, the relationship between the phase difference PHDT and the control voltage V2 is as shown in FIG. 11.

FIG. 12 is a flowchart showing a procedure for calculating PWM 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 (9),
The proportional control voltage V1 is calculated (S44 chip S31).

Next, the state of the steady state flag that was reset or set in step Sll or S12 in FIG. )～(12
) is calculated based on (step 833).

On the other hand, if the steady state flag is set and the motor rotational speed has reached the steady state, V2 is calculated based on the above equations (13) to (15) (step S34).

Then, V1 obtained in step S31 and step 5
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 small during the rise until the steady state is reached, and during the steady state, the control voltage due to the phase difference is relatively large.

In other words, among the control signal components constituting the motor control voltage, the proportional control component 45 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 commanded speed at the time of startup, and also to improve the followability of the speed at steady state, and to prevent the servo motor 10 from adjusting.

Note that the method of changing the ratio of the phase difference control component among the motor control signal components is not limited to the above-mentioned embodiment, and may be as follows.

Based on the above equations (10) to (15), when determining the control voltage v2 based on the phase difference, V2max is set to a relatively small predetermined value S at the rising edge when the flag is in the reset state, and V2max is set to a relatively small predetermined value S when the flag is in the set state. In the range, V2max is set to a relatively large predetermined value L.

Alternatively, when determining the control voltage v2 based on the phase difference,
The above formula (1
Calculated based on 0) to (]2) or (13) to (15). However, if the flag is 46 (noset 1/state rise 1), V 2 max
is a relatively small predetermined value S, and the flag is set to 1.
- In the steady state region, V2max is set to a relatively large predetermined value L.

Furthermore, the control voltage (2) due to the phase difference is always calculated by the same method, for example, based on the above equations (13) to (15),
A method may be adopted in which the proportional control component V] is increased or decreased depending on whether it is in a steady state or in a steady state.

FIG. 13 is a block diagram showing a specific configuration example of the PWM unit 16, and FIG. 14 is a block diagram showing a specific configuration example of the PWM unit 1.
This is a timing chart 1 for explaining the operation.

The PWM unit 16 includes a set signal generation section 161,
PWM data register 162 and down counter] 63
and an RS flip-flop 164.

The set signal generator 161 generates a set signal at regular intervals. This set signal generating section 16
1 is constituted by a ring counter, for example, and is designed to generate a set 1 signal every time a certain number of reference clocks are exceeded.

The PWM data register 162 is for holding PWM data given from the control unit 14. The PWM data given from [control unit] 4 is expressed by the above-mentioned formula (8
) is the voltage data determined by That is, it is the voltage VO obtained by correcting the proportional control voltage V] of equation (9) with the control voltage V2 based on the phase difference data PHDT. This PWM
The data is used to determine the duty of the PWM output signal output from the PWM unit 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 1.16 is as follows.

When a set signal is output from the set signal generation unit 61, the contents of the PWM data register 162, that is, the PWM data given from the control unit 14, are set in the down counter 163, and the set signal causes the flip-flop 164 to be set to the down counter 163. is set. Therefore,
The output of the flip-flop 164, that is, the PWM 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", the flip-flop 164
give a signal. Therefore, the output of FlipFlosop] 64 is inverted to the 1-1 novel.

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 a 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 be applied to the case where the applied voltage is calculated using other than PWM signals.

49. 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 rotation speed reaches a steady range, it is resistant to noise, etc., and the proportion of the phase difference control component in the control signal is relatively increased, so it has excellent followability to load fluctuations and maintains a stable constant state. Speed control is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of a drive control circuit of 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. 50 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 shows step S] in FIG. 3, which is a further improvement of the control in FIG. 3. 3 is a flowchart showing control contents that can be replaced with 0-312. 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 SIO to S12 in FIG. 3. 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 1 representing a phase difference detection processing procedure in an 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. 51 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 1 showing a procedure for calculating PWM data by the control unit 14. 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...Low reencoder, 13...
・Encoder signal input section, 14...control section, 15...
・Speed command signal input section, 16...PWM unit, M
1, M2...indicates memory. 52 2 1+1'1 22 eN 1 z C z 2 times four nieces O-

Claims (1)

[Claims] 1. The motor is controlled by a control signal including a proportional control component based on the speed difference and a phase difference control component based on the phase difference between the command signal and the detection signal so that the motor rotation speed becomes equal to the command speed. A motor control device that performs feedback control, and has a data calculation means that calculates data related to motor rotation speed at each predetermined timing, and a plurality of storage areas that can store data related to the motor rotation speed for a predetermined plurality of times in chronological order. 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, the oldest data is discarded, and the currently calculated data is placed in the latest data storage area. Compare the data corresponding to the middle of the size among the multiple data stored in the storage means 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 determining means for determining whether or not the motor rotation speed has reached a steady range based on whether or not the data is within a predetermined range; A motor control device comprising: control component changing means for relatively increasing a phase difference control component among control signal components for feedback controlling the motor when it is determined that the motor is feedback-controlled. 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 and a phase difference control component based on the phase difference between the command signal and the detection signal so that the motor rotation speed becomes equal to the command speed. a data calculation means for calculating data regarding the motor rotation speed at each predetermined timing; a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in chronological order; Storage means for shifting the already stored data one by one one by one and discarding the oldest data each time data related to motor rotational speed is calculated, and storing the currently calculated data in the latest data storage area; Determine whether the calculated latest data corresponds to the data corresponding to the middle of the plurality of data stored in the storage means or whether it is within a predetermined first range with respect to the data. a first determining means; a second determining means for determining whether the difference between the maximum data and the minimum data among the plurality of data stored in the storage means is within a predetermined second range; The determining means determines that 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 the second determining means determines that the latest data corresponds to the data corresponding to the center of the data, or is within a predetermined first range with respect to the data, and the second determining means When the difference is determined to be within a predetermined second range, a determining means determines that the motor rotational speed has reached a steady range, and when the determining means determines that the motor rotational speed has reached a steady range, A motor control device comprising: control component changing means for relatively increasing a phase difference control component among control signal components for feedback controlling a motor. 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 and a phase difference control component based on the phase difference between the command signal and the detection signal so that the motor rotation speed becomes equal to the command speed. a data calculation means for calculating data regarding the motor rotation speed at each predetermined timing; a plurality of storage areas capable of storing data regarding the motor rotation speed for a predetermined plurality of times in chronological order; Storage means for shifting the already stored data one by one one by one and discarding the oldest data each time data related to motor rotational speed is calculated, and storing the currently calculated data in the latest data storage area; Determine whether the calculated latest data corresponds to the data corresponding to the middle of the plurality of data stored in the storage means or whether it is within a predetermined first range with respect to the data. a first determining means for determining whether the latest data is within a predetermined second range with respect to predetermined target rotational speed data; It is determined that the latest data corresponds to the corresponding data or is within a predetermined first range with respect to the data, and the second determination means determines that the latest data is within a predetermined second range with respect to the target rotation speed data. A determining means for determining that the motor rotational speed has reached the steady range when it is determined that the motor rotational speed has reached the steady range, and a control signal component that performs feedback control of the motor when the determining means determines that the motor rotational speed has reached the steady range. A motor control device comprising: control component changing means for relatively increasing a phase difference control component.