JP2820756B2 - Motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a motor control device, and in particular, can accurately determine whether or not a motor rotation speed has reached a steady range, and has reached a steady range. The present invention relates to a motor control device for controlling the rotation speed of a motor at a constant speed so as to match a target speed.

<Prior Art> After the motor reaches a steady state from the transient response range, a PLL (phase-lock) is used to control the motor at a constant speed.
An ed loop) control method and an integral control method are known.

Each of the control methods described above is sufficiently effective as constant speed control after the motor has reached the steady range.

<Problems to be Solved by the Invention> By the way, in a transient response region in which the rotation speed of the motor rises to a steady region, in general, proportional control for applying a voltage proportional to the speed difference between the target speed and the detected speed to the motor is not performed. Done. Then, when the detected speed reaches a predetermined percentage of the target speed, for example, within 95%, it is determined that the motor rotation speed has reached the steady range, or the acceleration component is determined based on the previous detected speed and the current detected speed. The calculated value was used to determine that the motor rotation speed had reached the steady range.

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

Further, in the method of calculating the acceleration and determining whether or not the value has reached the steady-state region based on the calculated value, the acceleration component may be determined to be substantially zero due to noise, vibration, or the like even in the transient response region. In some cases, it was erroneously determined that the vehicle was in the steady range.

If it is not determined that the rotation speed of the motor has reached the steady-state range as in the former case, it is not possible to enter the PLL control or the integral control. Shooting is severe, and it takes time for the rotation speed of the motor to stabilize.

In addition, as in the latter case, if it is determined that the steady state has been reached despite the transient response range due to an erroneous determination, the PLL
Normal control cannot be performed even if the control is shifted to control.

Therefore, it is necessary for the motor control device to be able to accurately detect that the motor rotation speed has changed from the transient response region to the steady region.

Also, after the motor rotation speed reaches the steady range, control must be performed so that the motor rotation speed does not deviate from the target speed, but in the conventional device, the detected motor rotation speed is affected by noise and the like. In many cases, accurate detection of the motor rotation speed is difficult, and constant speed control is difficult.

Therefore, the present invention has been made in order to solve the above-described disadvantages, and can accurately detect that the motor rotation speed has reached the steady-state region from the transient response region. After that, even if the speed detection signal fluctuates temporarily due to noise, etc., the motor rotation speed can be accurately detected without being affected by the fluctuation, and the motor constant speed control can be performed with good tracking performance. It is an object of the present invention to provide a motor control device capable of performing such operations.

<Means for Solving the Problems> The first invention is based on a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to the command speed. What is claimed is: 1. A motor control device for performing feedback control of a motor, comprising: a data calculating means for calculating data relating to a motor rotation speed at predetermined timings; Each time data relating to the motor rotation speed is calculated by the data calculation means, the stored data is sequentially shifted one by one to discard the oldest data and store the data calculated this time as the latest data. Storage means for storing in the area, and data corresponding to the center of large and small of the data of a plurality of times stored in the storage means. Data is compared with the latest data calculated this time, and based on whether the latest data corresponds to the data corresponding to the center of large and small or whether the data is within a predetermined range with respect to the data, the motor rotation speed is in a steady range. Determining means for determining whether or not the motor rotation speed has reached a steady range, and determining, by the determining means, a relative integral control component of a control signal component for performing feedback control of the motor. And a control component changing means for increasing the number of control components.

According to a second aspect of the present invention, there is provided a motor control in which a motor is feedback-controlled by a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to the command speed. An apparatus, comprising: a data calculating means for calculating data relating to a motor rotational speed for each predetermined timing; and a plurality of storage areas capable of storing data relating to the motor rotational speed for a plurality of predetermined times, in a new order. A storage means for sequentially shifting the already stored data one by one and discarding the oldest data, and storing the data calculated this time in the latest data storage area, The latest data calculated this time corresponds to the large and small center of the multiple data stored in the storage means. First determining means for determining whether the data corresponds to the data or is within a predetermined first range, and the maximum data and the minimum data among a plurality of data stored in the storage means. The latest data corresponds to the data corresponding to the center of the large or small area, or the predetermined data is determined by the second determining means and the first determining means for determining whether the difference from the data is within a predetermined second range. Is determined to be within the first range, and when the difference between the maximum data and the minimum data is determined to be within the predetermined second range by the second determination means, the motor rotation speed reaches the steady range. When the determination unit determines that the motor rotation speed has reached the steady state range, the control component change that relatively increases the integral control component among the control signal components for performing feedback control of the motor. hand A motor control device which comprises a.

Further, the third invention provides a motor control for feedback-controlling a motor by a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to the command speed. An apparatus, comprising: a data calculating means for calculating data relating to a motor rotational speed for each predetermined timing; and a plurality of storage areas capable of storing data relating to the motor rotational speed for a plurality of predetermined times, in a new order. A storage means for sequentially shifting the already stored data one by one and discarding the oldest data, and storing the data calculated this time in the latest data storage area, The latest data calculated this time corresponds to the large / small center of the multiple data stored in the storage means. First determining means for determining whether the data corresponds to the data or is within a predetermined first range with respect to the data; the latest data is within a predetermined second range with respect to the predetermined target rotation speed data; The second discriminating means and the first discriminating means for discriminating whether or not there is the latest data, it is determined that the latest data corresponds to the data corresponding to the center of the large or small, or within the predetermined first range for the data, and , Second
When the determination unit determines that the maximum data is within a predetermined second range with respect to the target rotation speed data, the determination unit determines that the motor rotation speed has reached a steady range. A control component changing unit that relatively increases an integral control component among control signal components for performing feedback control of the motor when it is determined that the rotation speed has reached a steady range; is there.

<Operation> According to the present invention, data relating to the motor rotation speed is calculated at each predetermined timing.

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

Then, the data corresponding to the center of the large and small data among the data for a plurality of times stored in the storage means by sorting is obtained, and the data is compared with the latest data calculated this time.

As a result, according to the first invention, if the latest data corresponds to the data corresponding to the center of the size 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 not, the motor rotation speed is determined to be in the transient response range.

When it is determined that the motor rotation speed has reached the steady range, the integral control component of the control signal components for performing feedback control of the motor is relatively increased.

According to the second invention, the latest data calculated this time corresponds to the data corresponding to the center of the large and small of the data for a plurality of times stored in the storage means, or the predetermined data is If the difference between the maximum data and the minimum data among the data for a plurality of times stored in the storage means is within a predetermined second range, the motor rotation speed reaches the steady range. It is determined that it has been done.

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

Further, according to the third invention, the latest data calculated this time corresponds to the data corresponding to the center of the large and small of the data for a plurality of times stored in the storage means, or the predetermined data is When it 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 integral control component among the control signal components for performing feedback control of the motor is relatively increased.

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

FIG. 1 is a block diagram showing a configuration example of a control circuit of a DC servomotor for driving an optical system of a copying machine.

The DC servo motor 10 is of a permanent magnet field type, is driven to rotate by the driver unit 11, and moves the optical system 17.

A rotary encoder 12 is connected to a rotation shaft of the servo motor 10. As already known, the rotary encoder 12 outputs a speed detection pulse every time the servo motor 10 rotates by a predetermined minute angle. From the rotary encoder 12 of this embodiment, A-phase and B-phase speed detection pulses (speed detection signals) whose periods are equal to each other and whose phases are shifted from each other by 90 degrees are output. A phase, for example, 200 speed detection pulses are output.

Note that, instead of the rotary encoder 12, another device that outputs a pulse periodically interlocked with the rotation of the servo motor 10 may be used.

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

The control unit 14 stores an RO storing a CPU, a program, and the like.
M, RAM etc. to store necessary data are provided,
Processing for calculating the difference between the command speed and the detected speed, processing for detecting the arrival of the motor rotation speed in the steady range, processing for calculating proportional integral data for controlling the servomotor 10, and the like are performed.

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

The proportional integral control unit 16 is a unit for generating a control signal based on the proportional integral data given from the control unit 14. The control signal output from the proportional-integral control unit 16 controls the rotation speed of the servomotor 10.

The driver unit 11 determines the direction of rotation of the servo motor 10 and performs braking based on a driver unit drive signal provided from the control unit 14.

FIG. 2 is a diagram showing a configuration of the encoder signal input unit 13. In this embodiment, the encoder signal input unit 12
By adopting the configuration shown in the drawing and devising the signal reading by the control unit 14, accurate speed detection can be performed and the rotation speed of the servo motor 10 can be correctly determined whether it is in a transient response region or a steady region. .

Referring to FIG. 2, an encoder signal input unit will be described.
13 includes a rising detection circuit 131 for detecting a rising edge of an A-phase speed detection pulse sent from the rotary encoder 12;
A free-running counter 133 having a bit configuration and a rising detection output of the rising detection circuit 131 are used as a capture signal, and a capture register 134 is provided which reads and holds the count number of the free-running counter 133 using the capture signal as a trigger.

The reference clock is a reference clock serving as a reference for the operation timing of the entire circuit shown in FIG. 1. When the circuit is constituted by a microcomputer, a machine clock is used. If there is no such reference clock, a reference clock generation circuit may be provided.

The encoder signal input unit 13 further includes an up / down detection unit 135 and an up / down counter 136. The up-down detector 135 determines the level of the B-phase rotation pulse when the rising detection output of the A-phase speed detection pulse is given from the rising detection circuit 131, and determines whether the B-phase rotation pulse is at a high level or a low level. Is used to determine whether the servo motor 10 (FIG. 1) is rotating forward or reverse. The up / down counter 136 counts up or down the detection output of the rise detection circuit 131 based on the discrimination output of the up / down detection unit 135.

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

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

Therefore, within the predetermined sample time ΔT, n speed detection pulses are counted by the up / down counter 136, and during this time, the count number of the reference clock counted by the free running counter 133 is measured. The number N can be calculated.

That is, the rotation speed N [rpm] of the servo motor 10 is f [Hz] of the frequency of the reference clock, and A is output from the rotary encoder 12 by one rotation of the servo motor 10.
The number of phase speed detection pulses is C [ppr], the content of the current capture register 131 is CPT _n , and the previous capture register 1
If the content of 31 is CPT _n-1 and the number of speed detection pulses is n, Can be calculated.

Here, in the equation (1), since the reference clock frequency f and the speed detection pulse number C are constants, Becomes

Figure 3, together with the control unit 14 calculates the rotational speed data N _n reads the contents of the capture register 134 and the up-down counter 136 for each sample time Delta] t, based on the rotational speed data N _n calculated motor rotation This shows a rotational speed detection processing procedure for determining whether the speed is in a transient response region or a steady region and determining the control rotational speed N.

The sampling time Δt is set to an appropriate time that satisfies the following equation: Δt ≧ X = CPT _n −CPT _n−1 (3)

 Next, a description will be given with reference to FIG. 2 and FIG.

In the control unit 14, the internal timer sets a fixed sample time Δt
Is reached (step S1), the timer is reset (step S2). Then, the contents of the capture register 134 and the up / down counter 136 are read (step S3).

Then, the count number CPT _n of the current read-out capture register 134, already by subtracting the count number CPT _n-1 of the capture register 134 was last read stored, determined the reference clock number X in one sample time Δt After that, CPT _n is stored (step S4).

Further, from the count number UDC _n of this read-out the up-down counter 136, already by subtracting the count number UDC _n-1 of the up-down counter 136 was last read stored speed detection pulses in one sample time Δt n
Is obtained, UDC _n is stored (step S5).

After that, based on the above equation (2), the rotation speed data N _n (n is a natural number) calculated at the current sample timing, and 1, 2, 3,.
And increase. ) Is required (step S6).

Next, in step S7 to S12, it is determined that authenticity of the rotational speed data N _n calculated in step S6, the rotational speed N is determined for a control.

FIG. 4 shows two types of memories M1 and M2 used in the processing of steps S7 to S12.

In FIG. 4, a memory M1 is for storing five rotation speed data in order from the newest one, and an area for storing old rotation speed data from an area for storing new rotation speed data. , Five storage areas E1 to E5 are sequentially provided. That is, the current (latest) rotation speed data N _n is stored in E1, the previous rotation speed data N _(n-1) is stored in E2, the previous rotation speed data N _(n-2) is stored in E3, and E4 is stored in E4.
, The rotation speed data N _{(n-3) three} times before is stored, and the rotation speed data N _(n-4) four times before is stored in E5.

The memory M2 is a memory for sorting the five rotation speed data N _{n to} N _(n−4) stored in the memory M1, that is, rearranging the rotation speed data N _{n to} N _(n−4) in descending order, and has five storage areas E11 to E15.
have. If five rpm data N _n to N stored in the memory M1 _(n-4) is sorted, in the area E11 of the memory M2, for example, of the five speed data N _n ~N _(n-4) The largest one is the second largest in area E12, the third largest in area E13 is four in area E14.
The largest one is stored in the area E15, and the smallest one is stored in the area E15. Therefore, when sorting is performed,
In the area E13, among the five rotation speed data stored in the memory M1, rotation speed data corresponding to the center of the large and small rotations is stored.

The memories M1 and M2 are not limited to storing five rotation speed data, but may be any storage device for storing three or more rotation speed data, preferably an odd number.

Returning to FIG. 3, the description of the rotation speed data
When N _n is calculated and stored in the memory M1 5 single rotational speed data N _n to N _(n-4) is shifted (step S7).
As a result, the previous data N _n is the previous rotation speed data N
_{In the} area E2 as _(n-1) , the data N _(n-1) so far is 2
The previous rotation speed data N _(n-2) is stored in area E3, and the previous data N _(n-2) is output three times earlier as rotation speed data N _(n-3) in area E4. N _(n-3) is stored in area E5 as rotation speed data N _(n-4) four times before, and the oldest data N _(n-4) (the rotation speed data five times before ₎ ) Will not be remembered.

Also, the latest rotation speed data N _n calculated this time is
It is stored in E1 (step S8).

Next, the sorting of five speed data N _n to N stored in the memory M1 _(n-4) comprises a current rotational speed data N _n, in the area E11~E15 memory M2, five rpm Data N _{n to} N _(n−4) are stored in descending order (step S
9). As a result, the area E13 has five rotation speed data N _n
To N (to be referred to as "Central Data N _m" it) rotational speed data corresponding to the magnitude center of the _(n-4) is stored.

Then, the rotational speed data N _n of the current stored in the area E1 of the memory M1 is compared with the central data N _m which is stored in the area E13 of the memory M2, in a predetermined range of N _n is N _m It is determined whether or not there is (step S10). That is, whether the latest rotation number data N _n that is calculated this time is within a predetermined range of the data N _m, which corresponds to the magnitude center of the five data of the current and past 4 times represented by the following formula determined Is done.

N _m (1−α) ≦ N _n ≦ N _m (1 + β) (4) where α and β can be accurately determined that the motor rotation speed set in advance by experiment or calculation has reached the steady state range. the value, compared noise due to the data change amount, n _n is set to whether or not the apparent values are changed larger with respect to n _m.

When the current rotational speed data N _n is not within the range indicated by the above equation (4), the speed change is relatively large, the motor rotational speed is determined to be a transient response area, constant region flag Is reset, and the latest rotation speed data _Nn is selected and determined as the control rotation speed N (step S11).

On the other hand, if it is within the range that the latest rotation number of data N _n represented by the above formula (4), the speed change is relatively small,
It is determined that the motor rotation speed has reached the steady range, the steady range flag is set, and the control speed N is set to the central data N _m
Is determined (step S12).

As described above, in the process of step S7 to S12, in a range of central data N _m of the five data of the current and past 4 times, whether containing the current rotational speed data N _n is determined by being, motor speed is a determination whether the transient response region or constant region, the latest rotation number data n _n is in the transient response area is, in the constant region central data n _m, respectively, as the control rotation speed n Adopted.

Therefore, in the transient response region, a change in the speed of the motor can be quickly dealt with. Further, in the constant region, instantaneous load fluctuation, the influence of such noise, even when the speed detection signal is temporarily changed, the signal N _n is not used for receiving such effects, the central data N _m control , Stable control can be performed.

Next, another control obtained by further improving the control of steps S10 to S12 in FIG. 3 will be described.

FIG. 5 is a flowchart showing control contents that can be replaced with steps S10 to S12 in FIG.

In the case of the control shown in FIG. 3, there is the following fear. In other words, during the period from the start of control until the steady state is reached,
If the speed detection signal has a vibration as indicated by the symbol A in FIG. 6A, it may be erroneously determined that the steady state has been reached even though the steady state has not been reached.

Referring to FIG. 6B, which is an enlarged view of the vibration A in FIG. 6A, when the rotation speed data N _n is calculated at time t _n ,
t _n ~t _(n-4) of five times the rotational speed data N _n ~N _(n-4) a memory
It will be stored in M1. Then, the latest data N _n
Is the data corresponding to the center of the large and small of these data. Therefore, only by the determination in step S10 in FIG. 3, it is erroneously determined that the steady state has been reached.

Therefore, in this embodiment, in order to prevent the erroneous determination as described above, step S10 corresponding to step S10 in FIG.
In addition to the determination in 10-1, the determination in step S10-2 is added.

In step S10-2, the maximum data Nmax (stored in the area E11 of the memory M2) and the minimum data Nmin (stored in the area E15 of the memory M2) of the five data of this time and the past four times. Difference) (Nmax
−Nmin) is within a predetermined range W.

The difference between the maximum data Nmax and the minimum data Nmin (Nmax-Nmi
If n) is not within the predetermined range W, for example, vibrations as shown in FIGS. 6A and 6B only occur in the speed detection signal, and it is determined that the steady range has not been reached. There is reset, the control rotation speed n is determined to be the latest rotation number data n _n (step S11).

The difference between the maximum data Nmax and the minimum data Nmin (Nmax-Nmi
If n) is within the predetermined range W, it is determined in step S10-1 that the determination that the speed has reached the steady range is not an erroneous determination due to vibration or the like, and the steady range flag is set.
Control revolution speed N is determined in the central data N _m (step
S12).

Thus, steps S10-1 and S10-2 are two steps.
Since the motor rotation speed is determined to be in the transient response region or the steady region in the determination of the stage, the above-described vibration occurs in the speed detection signal in the transient response region from the start of the control to the reaching of the steady region. Even if it does, it is not erroneously determined that the stationary region has been reached, and the stationary region reaching detection is accurately performed.

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

FIG. 7 is a flowchart showing still another control content which can be replaced with steps S10 to S12 in FIG.

In the case of the control in steps S10 to S12 in FIG. 3, if the rotation speed of the servo motor 10 has settled at a speed lower than the target rotation speed for some reason after the start of the control, it is erroneously considered that the steady range has been reached. There is a risk of being judged.

Therefore, in this embodiment, as shown in FIG. 7, step S1 of FIG.
In addition to the first-stage determination of step S10-1 corresponding to 0, the second-stage determination of step S10-2 is performed.

In step S10-2, the latest data N _n calculated this time
Is compared with the target rotation speed data N ₀ stored in the memory in advance, and it is determined whether or not the latest data _Nn is within a predetermined range of the target rotation speed data N ₀ . That is, whether the actual rotational speed data N _n is within the range indicated by the following equation is determined.

N ₀ (1−γ) ≦ N _n ≦ N ₀ (1 + δ) (5) where γ and δ are predetermined set values.

If not within the predetermined range is the latest rotation number of data N _n with respect to the target revolution speed data N _0, is becoming calm latest rotation speed data N _n at a lower rotational speed than the target revolution speed data N ₀ for some reason Therefore, in such a case, it is determined that the servo motor 10 has not reached the steady range, the steady range flag is reset, and the latest rotational speed data _Nn is used as the control rotational speed N. (Step S11).

On the other hand, if the latest rotation number data N _n is within a predetermined range with respect to the target revolution speed data N _0, the rotational speed of the servo motor 10 is constant region flag is determined to have arrived in the constant region is set, the control revolution speed N, the central data N _m which is not affected by noise or the like is used (step S1
2).

Thus, even in this control, step S10-1
In the two-stage determination of S10-2 and S10-2, it is determined whether the motor rotation speed is in the transient response region or the steady region. Therefore, even if the motor rotation speed is going to settle at a speed lower than the target rotation speed for some reason, Thus, the steady state arrival detection is accurately performed without being erroneously determined to have reached the steady area.

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

Next, the speed command signal input unit 15 in FIG. 1 will be described.

FIG. 8 is a block diagram showing a specific configuration example of the speed command signal input unit 15. The speed command signal input unit 15 includes a rising detection circuit 151 for detecting a rising edge of the speed command clock, a free running counter 152 for counting up the reference clock, and a rising detection output of the rising detection circuit 151 as a capture signal. A capture register 153 that reads and holds the count number of the free-running nig counter 152 using a capture signal as a trigger and an up-counter 154 that counts up an output pulse of the rising detection circuit 151 are provided.

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

 The operation of this circuit is as follows.

The speed command clock output from the apparatus main body, for example, the microcomputer on the control side of the copying machine main body, is applied to a rising detection circuit 151, and the rising detection circuit 151 detects a rising edge of the speed command clock. Since the output of the rise 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 rise of the speed command clock. Therefore, the content of the capture register 153 is read based on a certain rising detection signal, the content of the capture register 153 is read based on the next rising detection signal, and the difference between them is obtained. Can be counted. That is, the rotation speed N _{0 at} which the commanded speed is obtained
Can be obtained.

In this embodiment, instead of calculating the difference between the count number after the update and the count number before the update every time the content of the capture register 153 is updated, in order to further improve the detection accuracy, A reading method similar to that of reading the count number of the capture register 153 in the encoder signal input unit 13 is employed.

That is, the control unit 14 determines the contents of the capture register 153 and the up-counter 1 every predetermined sample time Δt.
Read the contents of 54, find the difference between the current read count and the previously read count in the capture register 153, and divide the difference by the difference between the current read count and the previous read count in the up counter. By doing so, a more accurate reference clock number within one cycle of the speed command clock is obtained.

Next, a method of calculating the proportional-integral data output from the control unit 14 will be described.

Assuming that the control voltage (proportional control voltage) based on the speed difference ΔN (= N ₀ −N) is e (t), the accumulated value of the speed differences, that is, the integrated control voltage based on the value obtained by integrating the speed difference ΔN is Σe (t). , proportional integration data voltage V0 to be output to the servo motor 10 in order to the rotational speed N to follow the command speed N ₀ of the servo motor 10 is expressed by the following equation.

V0 = Ae (t) + BΣe (t) (6) where A and B are predetermined coefficients, B = B _S at the time of rising, B = B _L at the time of steady state (B _S <B _L ) It is.

That is, in this embodiment, not only the proportional control voltage e (t) based on the speed difference ΔN (= N ₀ −N), but also the control voltage V0 corrected by the integral control voltage Σe (t) is output. ing. In a steady state, the ratio of the integral control voltage increases. The reason for this is to improve the followability with respect to the speed fluctuation in the steady state.

The proportional control voltage e (t) based on the speed difference ΔN is expressed by the following equation.

However, Ra: amateur resistance [Ω] K _T : torque constant [kgm / A] Ke: induced voltage constant [V / rpm] Io: no-load current [A] GD ² : moment of inertia by load and motor [kg m ² ] T _BL : Sliding load [kgm].

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

The integral control voltage Σe (t) is equal to the proportional control voltage e (t),
That is, it is a voltage obtained by accumulating the speed differences up to now.

FIG. 9 is a flowchart showing a procedure of calculating proportional integral data by the control unit 14.

For example, every time the control unit 14 determines the control rotation speed N by the processing shown in FIG.
The proportional control voltage e (t) is calculated and stored (step S31).

Next, the state of the steady-state flag reset or set in step S11 or S12 in FIG. 3 is determined (step S32). If the steady-state flag is reset and the motor rotation speed is in the transient response range, the coefficient B = B _S and (step
S33) If the steady-state area flag is set and the motor rotation speed has reached the steady-state area, B = B _L is set (step S33).
S34), control voltage V0 = Ae (t) + BΣe (t) is calculated (step S35).

Therefore, the integrated control voltage is relatively low at the time of start up to the steady state after the motor control is started, and the integrated control voltage is relatively increased at the steady state. In other words, of the control signal components constituting the motor control voltage, the proportional control component is relatively large in the transient response region and relatively small in the steady region.

As a result, the rise time of the motor rotation speed can be shortened,
In addition, it is possible to improve the followability of the speed in a steady state.

The present invention can be applied not only to the control of the optical system of a copying machine but also to a motor for controlling a reading device of a facsimile apparatus and other general motor control circuits.

<Effect of the Invention> Since the present invention is configured as described above, regardless of the magnitude of the load, when the motor rotational speed reaches the steady-state region from the transient response region, it can be reliably detected.

In addition, even if the speed detection signal is temporarily adversely affected by a momentary load change or noise, the influence is not shown in the determination result, and it is possible to accurately detect that the rotation speed has reached the steady range. .

Furthermore, after the motor rotation speed is in the steady range, it is resistant to noise and the like, and the ratio of the integral control component in the control signal is relatively increased. Control is possible.

[Brief description of the drawings]

FIG. 1 shows an optical system driving apparatus to which an embodiment of the present invention is applied.
FIG. 3 is a block diagram illustrating an electrical configuration of a drive control circuit of the DC servo motor. FIG. 2 is a circuit block diagram showing an electrical configuration of an encoder input unit according to the embodiment of the present invention. FIG. 3 is a flowchart showing a rotational speed detection processing procedure in the embodiment of the present invention. FIG. 4 is a diagram showing two memories M1 and M2 used in the steady area arrival detection process. FIG. 5 is a flowchart showing a control content which is a further improvement of the control of FIG. 3 and which can be replaced with steps S10 to S12 of FIG. FIG. 6A and FIG. 6B are diagrams for explaining a problem when a special vibration occurs in the speed detection signal. FIG. 7 is a flowchart showing still another control content which is a further improvement of the control of FIG. 3 and which can be replaced with steps S10 to S12 of FIG. FIG. 8 is a block diagram showing an example of an electrical configuration of a speed command signal input unit. FIG. 9 is a flowchart showing a procedure of calculating proportional-integral control data by the control unit 14. In the figure, 10 ... DC servo motor, 11 ... Driver part, 12
... Rotary encoder, 13 ... Encoder signal input section, 14
.. Indicates a control unit, 15 indicates a speed command signal input unit, 16 indicates a proportional-integral control unit, and M1 and M2 indicate memories.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02P 5 / 00,7 / 00-7/34 H02P 6/00

Claims (3)

(57) [Claims] 1. A motor control device for feedback-controlling a motor by a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to a command speed. A data calculating means for calculating data relating to the motor rotation speed at each predetermined timing; and a plurality of storage areas capable of storing the data relating to the motor rotation speed for a plurality of predetermined times in the order of newest one. Each time data relating to speed is calculated, the stored data is sequentially shifted one by one, the oldest data is discarded, and the data calculated this time is stored in the latest data storage area. Data corresponding to the center of the large and small of the stored data for multiple times and the latest data calculated this time To determine whether the motor rotation speed has reached a steady range, based on whether the latest data corresponds to data corresponding to the center of the size and whether the data is within a predetermined range. A control component changing unit configured to relatively increase an integral control component among control signal components for performing feedback control of the motor when the determination unit determines that the motor rotation speed has reached the steady range. A motor control device characterized by the above-mentioned. 2. A motor control device for feedback-controlling a motor by a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to a command speed. A data calculating means for calculating data relating to the motor rotation speed at each predetermined timing; and a plurality of storage areas capable of storing the data relating to the motor rotation speed for a plurality of predetermined times in the order of newest one. A storage means for sequentially shifting the already stored data one by one and discarding the oldest data and storing the data calculated this time in the latest data storage area every time data relating to the speed is calculated. The latest data is the data corresponding to the center of the large and small of the multiple data stored in the storage means. First determining means for determining whether the data is applicable or within a predetermined first range; difference between the maximum data and the minimum data among a plurality of data stored in the storage means; The latest data corresponds to data corresponding to the center of large and small, or the first data is determined by the first discriminating means. When it is determined that the motor rotation speed is within the predetermined range, and when the second determination unit determines that the difference between the maximum data and the minimum data is within the predetermined second range, it is determined that the motor rotation speed has reached the steady range. A control component changing unit that relatively increases an integral control component among control signal components for performing feedback control of the motor when the determining unit determines that the motor rotation speed has reached the steady range; Motor control apparatus according to claim Mukoto. 3. A motor control device for feedback-controlling a motor by a control signal including a proportional control component based on a speed difference and an integral control component obtained by integrating the speed difference so that the motor rotation speed becomes equal to a command speed. A data calculating means for calculating data relating to the motor rotation speed at each predetermined timing; and a plurality of storage areas capable of storing the data relating to the motor rotation speed for a plurality of predetermined times in the order of newest one. A storage means for sequentially shifting the already stored data one by one and discarding the oldest data and storing the data calculated this time in the latest data storage area every time data relating to the speed is calculated. The latest data is the data corresponding to the center of the large and small of the multiple data stored in the storage means. The first determining means determines whether or not the data is within a predetermined first range with respect to the data, and the latest data is within a predetermined second range with respect to the predetermined target rotation speed data. A second discriminating means for discriminating whether or not the latest data corresponds to the data corresponding to the center of the large or small, or is determined to be within a predetermined first range for the data; and When the second determination means determines that the latest data is within a predetermined second range with respect to the target rotation speed data, the determination means determines that the motor rotation speed has reached a steady range, and Control component changing means for relatively increasing an integral control component among control signal components for performing feedback control of the motor when it is determined that the motor rotation speed has reached the steady range. Motor controller.