JPH03198680A - Motor controller - Google Patents

Abstract

PURPOSE:To accurately control a steady range of a motor by deciding that a motor rotating speed falls within the range when data corresponding to a center of large and small values of latest data is to fall within a predetermined range and determined to fall within a predetermined range of target rotating speed data. CONSTITUTION:When data regarding the rotating speed of a motor 10 is calculated at each predetermined timing, the latest data is compared with data regarding a target rotating speed stored in a first storage means of a controller 14. When the latest data corresponds to the data of the center of large and small values of the data of a plurality of times stored in a second storage means of the controller 14 or falls within a predetermined range to the data corresponding to the center of the large and small values and falls within a range to the data regarding the target rotating speed, it is decided that the rotating speed of the motor 10 arrives at the steady range.

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 range. It is related to the device.

<Background of the Invention> PLL (phas
e-locked loop) control is well 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 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, 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.

<Problem to be solved by the invention> By the way, in the transient response range where the rotational speed of the motor is raised 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, it may be determined that the motor rotation speed has reached a steady range by reaching within 95%, or an acceleration component may be calculated based on the previous detected speed and the current detected speed, and the motor rotation speed may be determined to be steady based on that value. It was determined that the area had been reached.

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

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.

If it is not determined that the rotational speed of the motor has 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 response 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 the motor control device, it is necessary to be able to accurately detect when the motor rotation speed reaches the steady state range from the transient response range.

This invention was made in view of the above circumstances, and
It is an object of the present invention to provide a motor control device that can accurately detect that the motor rotation speed has reached a steady state range, and can perform steady state range control of the motor based on this detection.

Means for Solving the Problems> The present invention provides a data calculation means for calculating data regarding the motor rotation speed at each predetermined timing, a first storage means in which data regarding the target rotation speed is stored in advance, and data regarding the motor rotation speed. It has a plurality of storage areas capable of storing a predetermined plurality of times of data in order of newest, 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. A second storage means that discards the oldest data and stores the data calculated this time in the latest data storage area, and the latest data stored in the latest data storage area is data for multiple times stored in the second storage means. Among them, a first determining means for determining whether the data corresponds to the data corresponding to the center of magnitude or whether it is within a predetermined range with respect to the data corresponding to the center of magnitude, and the latest data is stored in the first storage means. The second determining means determines whether the target rotational speed data is within a predetermined range or not, and the first determining means determines whether the latest data corresponds to the data corresponding to the center of the magnitude or the data corresponding to the center of the magnitude. When the motor rotation speed is determined to be within a predetermined range with respect to the target rotation speed data, and the second determination means determines that the latest data is within a predetermined range with respect to the target rotation speed data, the motor rotation speed is in the steady range. The motor control device is characterized in that it includes a determining means that determines that the condition has been reached.

Further, in the present invention, the motor control device further controls the motor by increasing a phase difference control component in the motor control signal in response to the determination means determining that the motor rotation speed has reached a steady range. The invention is characterized in that it includes control signal output means for steady-state control.

Function> Data regarding the motor rotation speed is calculated at each predetermined timing.

When the data regarding the motor rotation speed is calculated, the data for a predetermined number of times in the past already stored in the second storage means are shifted one by one, the oldest data is discarded, and the data calculated this time is the latest data. stored in the storage area.

Next, whether the latest data corresponds to the data corresponding to the middle of the magnitude among the multiple data stored in the second storage means or is within a predetermined range with respect to the data corresponding to the middle of the magnitude. is determined.

Further, the latest data is compared with data related to the target rotation speed stored in the first storage means, and it is determined whether the latest data is within a predetermined range with respect to the data related to the target rotation speed.

As a result, if the latest data corresponds to the data corresponding to the center of magnitude or is within a predetermined range with respect to the data corresponding to the center of magnitude and small, and is within a predetermined range with respect to the data regarding the target rotation speed. , it is determined that the motor rotation speed has reached a steady range.

When the motor rotation speed reaches the steady range, the phase difference control signal component in the motor control signal is increased and the motor control is switched to steady range control.

<Embodiment> An embodiment of the present invention will be described below, taking as an example a case where the present invention is applied to a control circuit of a DC servo motor for driving 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, the voltage applied to the DC servo motor is PWM (pulse width modulat
jon) signal is used.

This DC servo motor 0 is of a permanent magnet field type, and is rotationally driven by a driver section 11.
Move 7.

Rotary encoder 12 is installed on the rotation axis of servo motor 0.
are connected. As already known, the rotary encoder 12 outputs a speed detection pulse every time the servo motor o rotates by a predetermined minute angle. The low-resolution 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, For each phase, for example, 200 speed detection pulses are output.

The speed detection pulse output from the low-resolution encoder 12 is given to the encoder signal input section 13. The encoder signal human 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 low-resolution 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, and the speed command signal and the speed detection signal. Processing for calculating the phase difference of , processing for detecting that the motor rotation speed has reached a steady range, processing for calculating P0 WM 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 the speed command signal input section 15 and then provided to the control section 14 .

The control section 14 executes arithmetic processing based on each human power signal, calculates PWM data, and provides it to the PWM unit 16, and also provides a driver section drive signal to the driver section 11 described above.

The PWM unit 16 receives PW from the control unit 14.
PWM of pulse width (output duty) according to M data
This is a unit for generating signals. The servo motor 1 is activated by the PWM signal output from the PWM unit 16.
0 rotation speed is controlled. Further, the driver unit drive signal determines the rotation direction of the servo motor 10 and performs braking.

By the way, in order to rotate the servo motor 10 at a desired command speed, it is necessary to accurately detect the rotation speed of the servo motor 10.

Therefore, in this control circuit, the encoder signal human power section 13
The configuration is as shown in FIG. 2, and the signal reading by the control section 14 is devised so that accurate speed detection can be performed.

To explain with reference to FIG. 2, encoder signal human power section 1
3 includes a rise detection circuit 1 that detects the rise of the A-phase speed detection pulse sent from the low reencoder 12.
31, up-count the reference clock, e.g. 16
A capture register 134 is provided, which uses the bit-configured free running counter 133 and the rise detection output of the rise detection circuit 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 when the circuit is composed of a microcomputer, a machine clock is used. Also, if there is no such reference clock,
Two reference clock generation circuits 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. In addition, up/down counter 13
6 counts the number of times the rising edge of the speed detection pulse is detected, in other words, the number of speed detection pulses is counted by 3.

Therefore, within a predetermined sampling time ΔT, if n rotation pulses are counted by the up-down counter 136 and the number of reference pulses counted by the free running counter 33 during that period is measured, the rotation The number N can be calculated.

In other words, the rotation speed N [rpm] of the servo motor 10 is the frequency of the reference clock f [Hzl], and the number of A-phase rotation pulses output from the row encoder 12 when the servo motor 10 rotates once is C [ppr]. ], the content of the current capture register 131 is CPT, the content of the previous capture register 131 is CPT, the content of the previous capture register 131 is CPT, l...
(1) It can be calculated as 4.

Here, in equation (1), since the reference clock frequency f and the number of rotational pulses C are constants, N , , n A = agony (2)
CPT, -CPT, lXX: CPTo -CPT, -1.

FIG. 3 shows that the control unit 14 samples the contents of the capture register 134 and the up/down counter 136 at a sampling time Δ.
The rotation speed detection processing procedure for calculating the rotation speed N by reading every t is shown.

The sampling time Δt is set to an appropriate time that satisfies Δt≧X=CPT, −CPTll−+ −(3).

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

The control unit 14 resets the timer (step S2) every time the internal timer reaches a certain sampling time Δt (step S1), and the capture register 134
Then, the contents of the up/down counter 136 are read out (step S3).

Then, 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,
After the number of reference clocks X within one sample time Δ is determined by subtracting , CPT, , is stored (
Step S4).

In addition, from the count number UDC, , of the up-down counter 136 read this time, the count number UDC, , of the up-down counter 136 that was already stored and read last time,
After the number n of rotational pulses within one sample time Δ is determined by subtracting l, UDCo is stored (step S5).

Then, based on the above equation (2), the servo motor 1
The rotation speed N of 0 is determined (step S6).

Next, the speed command signal input section 15 will be detailed in 6. Give an explanation.

FIG. 4 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 rise detection circuit 151 for detecting the rise of the speed command clock, a free running counter 152 for up-counting the reference clock, and a rise detection output of the rise detection circuit 151 are used as a capture signal, and the capture signal is used as a trigger to control the free running counter 152. A capture register 153 for reading and holding a count number and an up counter 154 for up counting the output pulses of the rising edge detection circuit 151 are provided.

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 of the encoder signal input section 13 described above.

The operation of this circuit is as follows.

The speed command clock output from the main unit side of the apparatus, for example, the computer on the control side of the copying machine main unit 7, is given to the rising edge detection circuit 151;
The rising edge of the speed command clock is detected at . 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 based on a certain rising detection signal, the contents of the capture register 153 are read based on the next rising detection signal, and the difference is found, the free running counter 152 in one cycle of the speed command clock
The number of counts can be measured. In other words, it is possible to obtain the rotation speed No. that corresponds to the command speed.

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. , a reading method similar to that used for reading the count number of the capture register 153 in the encoder signal manual 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. 5 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 13 of the encoder signal input section 13
1, when the rising edge of the speed detection pulse is detected (step 511), the count value of the free running counter 133 is read, and the value is stored as the phase comparison value PDT (step 9, tab 512). Since the free running counter 133 starts counting the reference clock from the start of motor control, the value of the phase comparison value PDT is a value corresponding to the time from the start of motor control to the current pulse rise detection point. Become.

Next, the phase reference value PPI. is calculated and stored according to the following equation (step 813).

PP I, =PP I <n-+r +SPD
-(4) where: PPI. −3,: Previously stored phase reference value SPD
: Number of reference clocks per cycle of speed command clock (
SPD is a fixed value. ).

However, since the initial value of PPI (-11) is zero, the phase reference value PPI corresponding to when the first rising edge of the speed detection pulse after the start of motor control is detected in step S11 above. The value will be SPD.

After this, the phase difference PHDT is calculated by the following formula and 0 and stored (step 514).

SPD Then, the above processing is repeated. That is, every time the rising edge of the speed detection pulse is detected (step 511)
, reading the count value of the free running counter 133 and the phase comparison value PDT. Update (step 512)
, phase reference value PPI. calculation and update (step 81
3) and calculation of phase difference PHDT (step 514)
is repeated.

After the start of motor control, when the second rise of the speed detection pulse is detected in step S11, step 3
The value of the phase reference value PP1 calculated in step 13 becomes 2SPD, and becomes 3SPD when the third rising edge of the speed detection pulse is detected. In other words, the phase reference value PPI calculated in step S13 is the product of SPD and the total number of speed detection pulses output from the start of motor control to the current rise of the speed detection pulse.

1 Since SPD is a fixed value depending on the period of the speed command clock, the phase reference value PPI calculated in step 813
, 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
Tn) 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 difference between the value (phase reference value PPI) of the speed command clock. Value according to cycle (SPD)
The phase difference PHDT is obtained 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.

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

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

The voltage vO that should be output to the servo motor 10 in order to make the servo motor follow
It is expressed by the following formula.

VO=V1+V2 (6) The control voltage V2 by the phase difference PHDT is determined as follows, assuming that the maximum value of the predetermined control voltage v2 is V2max.

(A) At the time of 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... (
7) (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−(8)3 (e) 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=+V2Illax −(9
) Therefore, the relationship between the phase difference PHDT and the control voltage (2) is as shown in FIG.

(B) In the case of steady region (a) When the phase difference is smaller than one cycle (-1<PHDT<+1) V2-V2max -PHDT -(10)(
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) V2 = -V2max - (11) (c
) 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) 4 V2 = 10V2max - (12) Therefore, the phase difference PHDT and the control voltage V2 The relationship with
The relationship shown in the figure is obtained.

After the start of motor control, until the speed rises and reaches the steady range, ■2 is calculated based on the above equations (7) to (9), and when the speed reaches the steady range, the above equations (10) to (12) are calculated. Based on v
2 is calculated. Therefore, after the start of motor control, the control voltage for the phase difference is relatively low during the rise until the steady state is reached, and during the steady state, the control voltage for the phase difference is relatively high. 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.

FIG. 8 shows a steady state reaching detection process by the control unit 14 for detecting that the speed has reached a steady state, and FIG. 9 shows two types of memories M1 and M2 used for this process.
It shows.

In FIG. 9, the memory M1 is for storing rotation speed data for five times in order from the newest one, and has an area for storing new rotation speed data to an area for storing old rotation speed data. Five storage areas E1 to E5 are provided in this order. That is,
The current (latest) rotation speed data N, (n is natural, and each time the rotation speed data is calculated, 1. 2. 3.
...and increases. ), E2 has the previous rotation speed data N(.-1), and E3 has the two previous rotation speed data N(n
2, but E4 has the rotation speed data Ntn-31 from three times ago,
E5 has the rotation speed data N from 4 times ago. -4, are respectively stored.

Memory M2 contains five rotational speed data N stored in memory Ml. -N+n-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 N7 to N(
. -4, is sorted, for example, five rotation speed data N, , ~N(
11-4, the largest one is in area E5, the second largest in 12, the third largest in area E13, the fourth largest in area E14,
The smallest ones are stored in area E]5. Therefore, when sorting is performed, in area E13,
Among the five rotation speed data stored in the memory M1, the rotation speed data corresponding to the center of the magnitude is stored.

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

The steady-state region attainment detection process shown in FIG. 8 is performed, for example, every time the rotation speed N is calculated in step s6 of the rotation speed detection process in FIG.

When the rotation speed N is calculated, the five rotation speed data Nn-N (TI-4+) stored in the memory M1 are shifted (step 521). As a result, the previous data N
, is the previous rotation speed data N (n-11 as area E2
Then, the previous data N<,, -1° is the rotation speed data N two times before. -2, to area E7 3, and the previous data N. -2, is the rotation speed data N, three times before. -3, to area E4, and the previous data N. -3) is the rotation speed data N, 4 times ago. -4,
The previous data N is stored in area E5 as the oldest data. -4, (the number of rotations from five times before) will no longer be stored.

Also, the latest rotation speed data N calculated this time.

is stored in area E1 (step 522).

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

4 are sorted, and areas E11 to M2 of memory M2 are sorted.
E15 contains five rotation speed data N. -N. -4, but
They are stored in descending order (step 823). 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 "
The central data (hereinafter referred to as "central data N□") is stored.

Next, the current rotation speed data N0 stored in the area E1 of the memory M1 is compared with the central data N stored in the area E13 of the memory M1, and it is determined whether or not it is within a predetermined range of No. is determined (step 524). In other words, it is determined whether the latest rotational speed data Nゎ is within the range expressed by the following equation.

N, (1-α)≦N, ≦N= (1+β)...
(13) However, α and β are values by which it can be accurately determined by experiment or calculation that the preset motor rotational speed has reached a steady range.

That is, in this step S24, it is determined whether or not the current rotational speed data N, , is within a predetermined range of data Nm corresponding to the middle of the five data of the current and past four times. .

This rotation speed data N. is not within the range shown by the above equation (13) (No in step S24), it is determined that the speed change, that is, the acceleration is relatively large, and the motor rotation speed is still in a rising state, Phase difference P
The current process ends without switching the relational expression of the control voltage v2 for the HDT.

If the current rotational speed data N is within the range shown by the above formula (13) (YES in step S24)
, the change in speed, that is, the acceleration, is relatively small, and it is tentatively determined that the speed has reached a steady range (the first stage of determination is made).

However, with this method, if the rotation speed of the servo motor 10 settles down to a speed lower than the target rotation speed for some reason after control starts, it may be incorrectly determined that the steady state region has been reached. There is.

Therefore, in this embodiment, in order to prevent the above-mentioned erroneous determination, the process of step S25 is performed.

In step S25, the latest data N calculated this time. is the target rotational speed data N stored in the memory in advance. The latest data N, , is compared with the target rotation speed data N. It is determined whether or not it is within a predetermined range (a second stage determination is made) (step 525). In other words, it is determined whether the latest rotational speed data N0 is within the range expressed by the following equation.

No (17)≦N,≦No (1+δ)...(1
4) 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. or target rotation speed data N. In this case, it is determined that the servo motor 10 has not reached the steady state region, and the relational expression of the control voltage v2 to the phase difference PHDT is changed. The current process is ended.

On the other hand, the latest rotation speed data Nfi is the target rotation speed data N.

If the rotational speed of the servo motor 10 is within a predetermined range, it is determined that the rotational speed of the servo motor 10 has reached a steady range, and the phase difference P
The control voltage for HDT ■ 2 - relational expression or the above formula (1
0) to (12), and this process is terminated.

As described above, according to this embodiment, the current rotational speed data N is within a certain range of the data N0 corresponding to the center of magnitude among the five data of the current time and the past four times. The first step is to determine whether or not the motor rotation speed has reached a steady range by determining whether or not the motor rotation speed has reached a steady state. Even if the detected signal changes significantly temporarily, the signal affected by this change is not used for comparative judgment.

Further, the latest rotation speed data N, , is predetermined target rotation speed data N. The second step is to determine whether the motor rotation speed has reached a steady range based on whether the motor rotation speed is within a predetermined range, so if the motor rotation speed is lower than the target rotation speed for some reason. If you try to settle down at a speed, it will not be mistakenly judged that you have reached a steady state.
Detection of reaching a steady state region is performed accurately.

In the above control, the first stage determination in step S24 and the second stage determination in step S25 may be for forward or backward movement.

The control voltage ■1 due to the speed difference ΔN is expressed by the following formula2 be done.

V1=Ra (GD2 ・Ay+Io+ IBL 375KT Δt KT+KeN = RaGD2.AN+KoN 37'5KT Δt +Ra CIO+position/KT ) -(15) However, Ra: amateur resistance [Ω] KT: 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 TBI: sliding load [kg+n].

The control unit 14 detects the rotation speed N of the servo motor 10 (step S6 in FIG. 3) and calculates the speed difference Δ from the command speed N0.
Each time N is calculated or the phase 3 difference PHDT is calculated (step 514 in FIG. 5), VO is calculated based on the above equations (6) to (14), and the PWM is adjusted accordingly. Output data. This PWM data 4;! , are sent to the PWM unit 16, and the servo motor 10 is controlled via the driver section 11.

FIG. 10 is a block diagram showing a specific example of the configuration of the PWM unit 16, and FIG. 11 is a timing chart for explaining the operation of the PWM unit 16.

The PWM unit 16 includes a set signal generation section 161,
PWM data register 162 and down counter 163
and an RS flip-flop 164.

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

The PWM data register 162 is for holding PWM data given from the control unit 14 or 4. The PWM data given from the control unit 14 is voltage data obtained by the above-mentioned equation (6). That is, it is the voltage VO obtained by correcting the voltage v1 in equation (15) with the control voltage V2 based on the phase difference data PHDT. This PW
M data is the PWM output from the PWM unit 16.
Used to determine the duty of the output signal.

The down counter 163 counts down each 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 signal is output from the set signal generating section 161, the contents of the PWM data register 162, that is, the control section 1
The PWM data given from 4 is sent to the down counter 16.
3, and the flip-flop 164 is set by the cert signal. Therefore, the output of flip-flop 164, that is, PW
The M signal becomes high level.

Next, the down counter 163 performs down counting 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 duty is determined from the value held in the PWM data register 162, that is, the voltage data calculated by equation (6), and a PWM signal is derived from the PWM unit 16.

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.

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

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

[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 block diagram showing an example of the electrical configuration of the speed command signal input section. FIG. 5 is a flowchart showing the phase difference detection processing procedure in the embodiment of the present invention. FIG. 6 is a graph showing the relationship between the control voltage v2 and the phase difference P7 HDT used at the time of speed rise. FIG. 7 is a graph showing the relationship between the control voltage v2 and the phase difference PHDT used in steady state. FIG. 8 is a flowchart showing the procedure for detecting the arrival of a steady state region in the embodiment of the present invention. FIG. 9 is a diagram showing two memories M1 and M2 used for the steady state reaching detection process. FIG. 10 is a block diagram showing a specific electrical configuration of the PWM unit. FIG. 11 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. 8

Claims (1)

[Scope of Claims] 1. Data calculation means for calculating data regarding motor rotational speed at each predetermined timing; first storage means in which data regarding target rotational speed is stored in advance; It has a plurality of storage areas that can store data in the order of the latest data, and each time the data calculation means calculates data related to the motor rotation speed, the data already stored is sequentially shifted one by one and the oldest data is discarded. and a second storage means for storing the data calculated this time in the latest data storage area; the latest data stored in the latest data storage area is stored in the second storage means;
a first determining means for determining whether data corresponding to the middle of the magnitude or within a predetermined range with respect to the data corresponding to the middle of the magnitude among the plurality of data stored in the storage means; The second determining means determines whether the latest data is within a predetermined range with respect to the target rotational speed data stored in the first storage means, and the first determining means determines that the latest data corresponds to the center of magnitude. or is within a predetermined range with respect to data corresponding to the center of magnitude, and the second determining means determines that the latest data is within a predetermined range with respect to the target rotation speed data. 1. A motor control device comprising: determination means for determining that the motor rotational speed has reached a steady range when the motor rotation speed has reached a steady range. 2. The motor control device according to claim 1 further comprises: increasing the phase difference control component in the motor control signal in response to the determining means determining that the motor rotational speed has reached a steady range; The present invention is characterized in that it includes a control signal output means for controlling the motor in a steady state region.