JPH03198678A - Detecting device for arrival at steady range in motor controller - Google Patents

Abstract

PURPOSE:To accurately detect that a motor rotating speed arrives at a steady range by comparing data corresponding to a center of large and small values with latest data calculated this time each time data regarding a motor rotating speed is calculated, and determining whether the speed arrives at the range or not. CONSTITUTION:Data regarding the rotating speed of a motor 10 is calculated at a predetermined timing. When data regarding the speed of the motor 10 is calculated, data of past predetermined times stored already in a storage means controller 14 are sequentially shifted by one, and data calculated this time is stored in a latest data storage area. Data corresponding to a center of large and small values of data of predetermined number stored in the storage means is compared with the latest data to determine whether the speed of the motor 10 arrives at a steady range or not. Thus, the fact that the speed of the motor 10 falls within the range can be accurately determined.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a steady state reaching detection device in a motor control device.

<Background of the Invention> PLL (phas
e-locked loop) control is well 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, and controls the motor speed. It is something to control.

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

<Problems to be Solved by the Invention> By the way, in the transient response region where the rotational speed of the motor is increased to a steady state region, proportional control is generally performed in which a voltage proportional to the speed difference between the target speed and the detected speed is applied to the motor. 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, when the detected speed reaches a predetermined percentage (for example, 95%) of the target speed, it is determined that the motor rotation speed has reached a steady range. There have been cases in which the speed has stabilized at a low speed (for example, 90% of the target speed) and it is not determined that the steady state region has been reached.

In addition, in the method of calculating acceleration and determining whether it has reached a steady state based on the 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. I can't.

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 steady-state region reaching detection device in a motor control device that can accurately detect when a motor rotation speed has reached a steady-state region.

Means for Solving the Problems> The present invention provides a motor control device that performs feedback control of a motor so that the motor rotation speed becomes equal to a command speed, a means for calculating data regarding the motor rotation speed at each predetermined timing; It has an area where data related to the motor rotation speed can be stored for a predetermined number of times in chronological order, and each time data related to the motor rotation speed is calculated, the already stored data is sequentially shifted one by one and the current data is calculated. By comparing the latest data calculated this time with the data corresponding to the middle of the size among the data of multiple times stored in the storage means and the latest data storage area. The present invention is characterized by comprising means for determining whether or not the motor rotational speed has reached a steady range.

Further, in the above-mentioned steady-state region reaching detection device in the motor control device, the discrimination means stores the latest data calculated at each timing in the storage means consecutively a predetermined number of times. It is characterized in that it is determined that the motor rotation speed has reached a steady range when it has a predetermined relationship with data corresponding to the center of magnitude.

The data regarding the motor rotation speed includes data that is directly proportional to the motor rotation speed as well as data that is inversely proportional to the motor rotation speed.

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

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

Then, by comparing the data corresponding to the middle of the predetermined number of data stored in the storage means with the latest data, it is determined whether the motor rotation speed has reached a steady range. .

More preferably, the latest data is continuously stored in the storage means a predetermined number of times and has a predetermined relationship with the data corresponding to the center of magnitude, for example, within a predetermined percentage of the data corresponding to the center of magnitude. If this state continues, it is determined that the motor rotation speed has entered the steady range.

<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 11 odulani).
on) 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 attached to the rotating shaft of the servo motor 10.
are connected. As is already well known, the low rotation encoder 12 outputs a speed detection pulse every time the servo motor 10 rotates by a predetermined minute angle. The rotary encoder 12 of this embodiment outputs A-phase and B-phase speed detection pulses (speed detection signals) that have the same period and are out of phase by 90 degrees, and when the servo motor 10 rotates once, each For example, 200 speed detection pulses are output.

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

The control unit 14 is equipped with a CPU, a ROM that stores programs, etc., a RAM that stores necessary data, etc., and performs calculation processing of the difference between the command speed and the detected speed, and the speed command signal and the speed detection signal. calculation process of phase difference, steady state reaching determination process, PWM for controlling servo motor 0
Performs data calculation processing, etc.

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

The control section 14 executes arithmetic processing based on each input 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 as a premise.

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 input section 1
3 includes a rise detection circuit 1 that detects the rise of the A-phase speed detection pulse sent from the rotary encoder 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,
A reference clock generation circuit may also 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.

Therefore, within a predetermined sampling time Δτ, if the up/down counter 136 counts n rotation pulses, and during that time the free running counter 133 measures the number of reference pulses, the number of rotations will be calculated based on that. N can be calculated.

In other words, the rotation speed N [rpm] of the servo motor 10 is determined by the frequency of the reference clock being f [Hz], and the number of rotation pulses of the A phase output from the rotary encoder 12 when the servo motor 10 makes one rotation C [ppr]. ], the contents of the current capture register 13] are CPT, and the contents of the previous capture register 1231 are CPTn-+, it can be calculated as follows (1).

Here, in equation (1), since the reference clock frequency f and the number of rotational pulses C are constants, N-nA nA CPT, , -CPTfi, X (2) However, A knee! -X60X: CPT, -CPTn-+.

FIG. 3 shows a rotation speed detection processing procedure in which the control unit 14 reads out the contents of the capture register 134 and the up/down counter 136 at every sampling time Δt to calculate the rotation speed N.

The sampling time Δt is set to an appropriate time that satisfies the following (3): 3 Δt≧X=CPT, -CPT, -1.

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

The control unit 14 resets the timer (step S2) and reads out the contents of the capture register 134 and the up/down counter 136 (step S1) every time the internal timer reaches a certain sampling time Δt (step S1).
3).

Then, from the count number CPT of the capture register 134 read this time, the count number CP T n of the capture register 134 read last time which is already stored is calculated.
After the number of reference clocks X within one sample time Δ is determined by subtracting -1, CPT is stored (
Step S4).

Also, from the count number UDC of the up-down counter 136 read this time, the count number UDC of the up-down counter 136 read last time which is already stored, .
After the number n of rotational pulses within one sample time Δ is obtained by subtracting 4 UDC, , 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 explained in detail.

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 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.

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 rise detection circuit 151, and the rise of the speed command clock is detected in the rise detection circuit 151. Since the output of the rising edge detection circuit 151 is given to the free running counter 152 as a capture signal, the contents of the capture register 153 are updated in response to the rising edge of the speed command clock. Therefore, 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 152 in one cycle of the speed command clock can be calculated. The number of counts can be measured. In other words, it is possible to obtain the rotational speed N that is the commanded speed.

6. In this embodiment, each time the contents of the capture register 153 are updated, the difference between the count after the update and the count before the update is calculated. 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. 5 shows a procedure for calculating the phase difference between the speed command clock and the speed detection pulse by the control unit 14.

7 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 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, phase reference value PP1. is calculated and stored according to the following equation (step 813).

PP I,=PP I o−n +SPD −(4
) Here, P P I Lfi-+) : Previously stored phase reference value SPD : Number of reference clocks during one period of speed command clock (SPD is a fixed value).

However, since the initial value of P P I +-++ is zero, the phase reference value P PIn corresponding to the first rise of the speed detection pulse after the start of motor control is detected in step S11. The value of is SPD.

Thereafter, the phase difference PHDT is calculated using the following equation 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 rising edge of the speed detection pulse is detected in step Sll, the process proceeds to step 3.
The value of the phase reference value PP1 calculated in step 13 becomes 2SPD, and becomes 3SPD when the rising edge of the third speed detection pulse is detected.

In other words, the phase reference value PPI calculated in step 813
The value of , is the product of the total number of speed detection pulses output from the start of motor control to the current rise of the speed detection pulse and SPD.

Since SPD is a fixed value depending on the period of the speed command clock, the phase reference value PP1 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
T, ) and the value (phase reference value PPIn) 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 PPIn) 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 0 is one cycle or more of the speed command clock, the phase difference PHDT can be accurately detected.

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.

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

VO−V1+V2 −(6) Phase difference P
The control voltage V2 by the HDT is determined as follows, assuming that the predetermined maximum value of the control voltage v2 is V 2 max.

(A) At 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- (V2IIlax /3) IIPHDT...
(7) 1 (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
) (e) When the phase difference is 3 cycles or more and the phase of the speed detection signal lags the phase of the speed command signal (PHDT≧+3) V2−+V2max −(9) Therefore, the phase difference PHDT and the control voltage The relationship with v2 is the 6th
The relationship shown in the figure is obtained.

(B) In the case of steady region (a) When the phase difference is smaller than one cycle (-1<PHDT<+1) V2-V2IIlax -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) 2 V2−−V2max −(1
1) (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−+V2IIlax −(12)
Therefore, the relationship between the phase difference PHDT and the control voltage V2 is as follows:
The relationship shown in FIG. 7 is obtained.

After the start of motor control, v2 is calculated based on the above equations (7) to (9) until the speed rises and reaches the steady range, and when the speed reaches the steady range, the above equations (10) to (12) are calculated. Based on v2
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 rotation speed from increasing to a speed much faster than the command speed at startup, and it is possible to improve speed followability during steady state.
Tax adjustment of the servo motor 10 can be prevented.

3. FIG. 8 shows the steady state reaching detection process by the control unit 14 for detecting that the speed has reached the 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 N7 is in El, and the previous rotation speed data N is in E2. -1) is the rotation speed data N from two times before E3. -2) is the rotation speed data N from three times ago in E4. −
3, and the rotation speed data N (11-41) of the previous four times are stored in E5.

Memory M2 contains five rotational speed data N stored in memory M1. -No-4, is a memory for sorting, that is, sorting in descending order of size, and has five storage areas E11 to E15.

Five rotation speed data N, stored in memory M1.

4 ~N (if n-4+ is sorted, memory M2
For example, five rotational speed data Nfi are stored in area Ell.
~ Ntn-4), the largest one is 2 in area E12.
The third largest one is in area E13, the fourth largest one is in area E14, and the fourth largest one is in area E13.
The smallest one in 15 is stored respectively. Therefore, when sorting is performed, area E13 has memory M
Among the five rotation speed data stored in No. 1, the rotation speed data corresponding to the center of the magnitude is stored.

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

The steady-state region attainment detection process shown in FIG. 8 is performed each time the rotation speed N is calculated, for example, in step S6 of the rotation speed detection process in FIG.

When the rotation speed N is calculated, five rotation speed data N4 to NIn-41 stored in the memory M1 are shifted (step 521). As a result, the data N up to that point 5 is the previous rotation speed data N,. −1°, and the previous data N Ll+−1 in area E2.
1 is the rotation speed data N from two times ago. −2, as area E
3. Data N up to that point. -2, the rotation speed data NL1-1 from three times ago is stored in area E4, and the data N up to that point is stored. -3, is the rotation speed data N, 4 times before. -4, and the previous data NLn-41 (rotation speed data from five times ago), which is the oldest data, is no longer stored.

Furthermore, the latest rotation speed data Nn calculated this time is stored in area E1 (step 522).

Next, the five speed data N1 to N, n4 stored in the memory M1 including the latest rotation speed data Nn are sorted, and the areas E11 to E15 of the memory M2 are
Five rotation speed data N, , ~N. -4) are stored in descending order (step 823). As a result, area E1
3 stores rotation speed data corresponding to the center of the five rotation speed data Nゎ to NLII-41 (this will be referred to as central data N, J).

6 Next, the current rotation speed data N7 stored in area E1 of memory M1 is compared with central data Nm stored in area E13 of memory M1, and whether or not it is within a certain range of N. is determined (step 524). In other words, it is determined whether or not the latest rotational speed data N, is within the range expressed by the following equation.

N□ (1-α)≦N7≦N,,l (1+β)...
(13) However, α and β are values that can be used to accurately determine whether the preset motor rotational speed has reached a steady state region through experiment or calculation.

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

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 the rising state 7. , the control voltage v for the phase difference PHDT
The current process ends without switching the relational expression 2.

This rotation speed data N. is within the range shown by the above equation (13) (YES in step S24), it is determined that the speed change, that is, the acceleration, is relatively small and the speed has reached a steady region, and the phase difference The relational expression of the control voltage with respect to is switched to that expressed by the above-mentioned equations (10) to (12), and this process is completed.

In this steady state reaching detection process, it is determined whether the current rotational speed data N1 is within a certain range of data N□ corresponding to the center of the size of the five data of the current and past four times. Since it detects whether or not the speed has reached a steady range, even if the speed detection signal changes temporarily due to the influence of instantaneous load fluctuations, noise, etc. Since the signal is not used for comparison, it is possible to accurately determine whether the speed has reached a steady range.

8 Also, because the current rotation speed data N satisfies equation (13) only once, it is not determined that the rotation speed of the servo motor 10 has reached the steady range, and when this continues for a predetermined number of times, It may be determined that the rotation speed of the servo motor 1o has reached a steady range.

The control voltage v1 due to the speed difference ΔN is calculated using the following formula (%) (14) Ra: Amateur resistance [Ω] KT torque constant [kgm/A] Ke: Induced voltage constant [V/rpm] Io: No load Current [A] GD2: Moment of inertia due to load and motor [kg
m2] 9 TBL: Sliding load [kgm.

The control unit 14 detects the rotation speed N of the servo motor 10 (step S6 in FIG. 3) and calculates the speed difference ΔN from the command speed N.
or calculate the phase difference PHDT ('M
Each time step 514) in Figure 5 is performed, the above equations (6) to (1
Based on 4), calculate vO and adjust PWM accordingly.
Output data. This PWM data is 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 0 set signal at regular intervals. This set signal generating section 161 is composed of, for example, a ring counter,
A set signal is generated 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. The PWM data given from the control unit 14 is expressed by the above-mentioned formula (6
) is the voltage data determined by That is, the voltage VO is obtained by correcting the voltage (1) in equation (14) with the control voltage (2) based on the phase difference data PHDT. This PWM 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.

1 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 also set by the set signal. 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", a heliset 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 rotation speed reaches the steady state from the transient response range, regardless of the magnitude of the load.

Furthermore, even if the speed detection signal is temporarily adversely affected by instantaneous load fluctuations, noise, etc., the effect will not appear in the determination result, and it is possible to accurately detect when the rotation speed has reached a steady range.

[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. 3. 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 PHDT 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 the steady state region. 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 an illustrative diagram showing two memories M1 and M2 used in 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... Rotary encoder, 13...
・4 Encoder signal input section, 14...control section, 15...
Speed command signal input section, 16...PWM unit, Ml
, M2...indicates memory. 5

Claims (1)

[Claims] 1. In a motor control device that performs feedback control of a motor so that the motor rotation speed becomes equal to a command speed, means for calculating data regarding the motor rotation speed at each predetermined timing; data regarding the motor rotation speed; It has an area that can store a predetermined number of times in chronological order, and each time data related to the motor rotation speed is calculated, the already stored data is sequentially shifted one by one, and the data calculated this time is stored as the latest data. By comparing the storage means stored in the data storage area and the data corresponding to the middle of multiple times of data stored in the storage means with the latest data calculated this time, the motor rotation speed can be determined. A steady-state region reaching detection device in a motor control device, comprising: determining means for determining whether or not the steady-state region has been reached. 2. In the steady state reaching detection device for a motor control device according to claim 1, the determining means stores the latest data calculated at each timing in a storage means consecutively a predetermined number of times. The present invention is characterized in that it is determined that the motor rotation speed has reached a steady range when it has a predetermined relationship with data corresponding to the center of the magnitude range.