JPS6337597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a speed control device for an electric motor, and particularly to a speed control device for a variable speed electric motor that is effectively used in copying machines and the like.

[Conventional technology]

A typical motor control device is configured to compare a commanded speed with an actual motor speed, and provide a return signal directly proportional to this deviation to a drive device to maintain the motor at a predetermined speed.

However, in electric motors for copying machines and the like, it is necessary to suppress rotational irregularities as small as possible regardless of load fluctuations, and the above-mentioned general techniques have been insufficient. As an example of improving this, JP-A No. 55-49989
As disclosed in the publication, the error words between the commanded speed and the actual measured speed of the motor are stored in time series, the output voltage applied to the motor is corrected based on changes in the error words, and the output voltage is A method has been proposed in which a motor is controlled by integrating voltage.

[Problem to be solved by the invention]

However, in this method, in order to store error words in time series, it is necessary to store them in the memory after performing calculations on the error words, which requires a certain amount of time for calculation, making it difficult to achieve high-speed response. It has the disadvantage of being lacking.

The purpose of the present invention is to
An object of the present invention is to provide a speed control device for an electric motor that can maintain a constant speed of an electric motor at high speed and minimize rotational pulsation.

[Means to solve the problem]

In order to achieve the above object, the present invention includes an electric motor 2 and a chopper circuit 1 for driving the electric motor 2.
, an encoder 3 for detecting the speed of this electric motor 2, a counter 4 for processing an output signal of this encoder, a keyboard 6 for giving a speed command to the electric motor 2, an output word 13, a speed word 15, and a command word 10. An input/output device, a calculation device 8 which is interposed between the input/output device 7 and the memory 9 and includes an output calculation section 14, a torque correction word 16, an acceleration/deceleration word 27, and a deviation word 12; Memory units 11, 17, 25, 26 for storing data,
28 and a memory 9 containing a plurality of constant words 18 to 24, the present speed word 15 given by the counter 4 at any time is stored in the memory section 25, and the previous speed word is stored in the memory section 26.
Calculated from the difference between the memory units 25 and 26 that store the speed words 15 in chronological order such that the previous time is transferred from the memory unit 25 to the memory unit 26, and the speed words 15 stored in these memory units 25 and 26. A memory unit 28 stores an acceleration/deceleration word 27 that is a negative value during acceleration and a positive value during deceleration, and the arithmetic unit 8 stores the motor speed command word 10 and the motor speed word 15 given by the keyboard 6. , calculate the deviation word 12 from the difference, select one of the constant words 19, 20, and 21 of the area according to the size of the deviation word 12, and select one of the selected constant words. Select one of the correction constant words 22, 23, and 24 corresponding to the correction constant word, correct the previous torque correction word 16 with the selected one correction constant word, and store the latest torque correction word 16. 17, an output word 13 obtained by adding the deviation word 12 multiplied by the proportional constant word 18, the torque correction word 16, and the acceleration/deceleration word 27 by the output calculation unit 14; , A speed control device for a motor is characterized in that the chopper circuit 1 for driving the motor 2 is controlled in accordance with the output word 13.

〔Example〕

Hereinafter, one embodiment of the configuration of the present invention will be described based on the drawings.

In FIG. 1, reference numeral 1 denotes a chopper circuit, and a motor 2 is connected to the output side of the chopper circuit 1, and an encoder 3 is attached to the shaft of the motor 2. Then, the output of encoder 3 is sent to counter 4.
and is sent to the input/output device 7 via the latch register 5. This input/output device 7 includes a command word 10, a speed word 15, and an output word 13, and transmits signals obtained from the latch register 5 and the keyboard 6 to the arithmetic unit 8.
or send the signal from the arithmetic unit 8 to the output word 13
It has a function to output as . The arithmetic device 8 is the first
As shown in the figure, the output calculation unit 14, the torque correction word 1
6, an acceleration/deceleration word 27, and a deviation word 12. Reference numeral 9 denotes a memory that stores data from the arithmetic unit 8 or stores a plurality of constant words and the like.
Incidentally, these input/output device 7, arithmetic device 8, memory 9, etc. are electronic elements, and are realized by, for example, a microcomputer.

Next, explaining the transmission and reception of signals, data from the latch register 5 is connected to form a speed word 15 (V _f ) in the input/output device 7.

The speed words are stored in memory sections 25 and 26 in chronological order.
is memorized. That is, when the speed word 15 detected in the current sampling is stored in the memory section 25, the speed word 15 previously stored in this memory section 25 is moved to the memory section 26, and this process is repeated every time the speed is detected. It means that it will be done.
Further, an acceleration/deceleration word 27 (ΔV _f ) is formed using this time-series speed word 15, and its value is stored in the memory section 28.

On the other hand, the output of the keyboard 6 forms a command word 10 (V _o ) of the input/output device 7, and this command word 10 is stored in the memory section 11. In addition, the output calculated by the output calculation section 14 in the calculation device 8 is transmitted to the input/output device 7.
form the output word 13 (OUT) of the input/output device 7.
It is connected to the chopper circuit 1 via. Furthermore, the calculation device 8 calculates the deviation word 12 (E=V _o −
V _f ) is formed. Furthermore, predetermined areas are divided according to the value of this deviation word 12, and according to the areas,
The torque correction word 16 (J _o ) is calculated and the result is stored in the torque correction word memory section 17 . Note that 1 in memory 9
8, 19, 20, 21, 22, 23, and 24 are constant words necessary for performing operations in the arithmetic unit 8.

Next, the operation of the control device configured as described above will be described.

The input/output device 7 takes in the value set by the keyboard 6 and forms a command word 10. This command word 10 is stored in the memory section 11 of the memory 9 unless changed. On the other hand, pulses are output from the encoder 3 according to the rotational speed of the electric motor 2, and although these pulses are not shown in the figure, they are counted by a counter 4 for a certain period of time, and this counted value is calculated after a certain period of time has elapsed. It is held in the latch register 5 later. The output of this latch resistor 5 forms the motor speed word 15 present in the input/output device 7. Now, if the value of the command word 10 is V _o and the speed word 15 of the motor is V _f , then in the arithmetic unit 8 E=V _o −V _f
is calculated to form a deviation word 12 (E=V _o -V _f ). This deviation word 12 is successively compared with constant words 19, 20, and 21 existing in the memory 9. In other words, the values of constant words 19, 20, and 21 are
If L ₁ , L ₂ , L ₃ , the correction constant word 22, 2 depends on whether the deviation word E is larger or smaller than L ₁ , L ₂ , L ₃ .
3 and 24 are selected. Now correction constant word 22,
Assuming that the values of 23 and 24 are K ₁ , K ₂ , and K ₃ , respectively, the values of E=V _o −V _f become L 1 , K 2 , and _{K 3 ,} respectively, as shown in FIG.
K ₁ , depending on where it is located in the area of L ₂ and L ₃
The constant words of the correction words K ₂ and K ₃ are selected. Then,
In the torque correction word 16 part of the arithmetic unit 8, K ₁ , K ₂ ,
K ₃ is selected, the calculation of J _o = J _o-1 −±K _o is performed, and the torque correction word 16 in the memory 9 is
The data is stored in the memory unit 17 of. Note that J _o-1 is the result of the previous calculation, and the value of the constant K _o is added to or subtracted from this value.

FIG. 3 shows the state of correction according to the deviation word E. For example, when the motor 2 is stopped at the beginning of startup, E = V _o - V _f = V _o , the constant word for correction is _K2 , and J _o = J _{o-1 +} K2. .
Next, when the electric motor is accelerated and enters the region L ₃ <E < L ₂ , J _o =J _o-1 −K ₂ .

Here, the specific values are K ₁ = 1, K ₂ = 2,
Consider the value K ₃ =4. When you want to adjust the final motor speed V _f to point 2 in Figure 3, if the speed V _f is now at point A, then E = V _o - V _f is
It is between L ₂ <E < L ₁ and K _o =K ₁ =1 is selected. Therefore, J _o = J _o-1 +1, and the torque correction term
J _o increases. Note that this calculation is repeatedly executed after a predetermined sampling time has elapsed, so the value of the correction word J _o increases with time. Therefore, the electric motor 2 is accelerated and eventually reaches point B. Then E=V _o −V _f is L ₃
Since it is between <E<L ₂ , K _o = K ₁ = 1, and this time
J _o =J _o-1 -1, and the torque correction word J _o decreases. Therefore, after this point, the electric motor is decelerated in the opposite way to the previous point and reaches point C. Then, J _o = J _o-1 + 1 again, which accelerates and eventually settles on point 2. Moreover, the value of E=V _o −V _f is E>L ₁ , L ₃ >E>0.
Since K ₂ =2 and a correction of J _o =J _o-1 ±2 is performed, a stronger force acts than when K ₂ =1. Furthermore, when E≦0, K ₃ =4, which acts to return to the two points with an even greater force.

Furthermore, the speed word 15 is chronologically stored in the memory unit 2.
5, 26, and this value is stored in V _fo , V _fo-1
Then, acceleration/deceleration 27 (ΔV _f ) is formed by calculating ΔV _f =V _{fo -1} −V _fo . In other words, when ΔV _f =0, the speed of the motor is constant, and when ΔV _f >0, it is decelerating. Therefore, when ΔV _f =0, the value M=0 of the acceleration/deceleration word 27 is formed in the memory section 28 . and,
When ΔV _f > 0, M=+P; when ΔV _f < 0, M=-
P is formed in the memory section 28. Note that M is a general term for the values in the memory section of acceleration/deceleration words, and +P and -P are
This is a constant set in advance. Specifically, M=+1, M=-1, and M=0.

At this time, the value of acceleration/deceleration word M and the speed word of the motor
The relationship with V _f is shown in Figure 4. As is clear from the figure, M=-P during acceleration, and M=-P during steady state.
0, and M=+P during deceleration.

Next, in the output calculation unit 14 of the output word 13,
The output word 13 is formed by adding the value obtained by multiplying the deviation word 12 by a proportional constant word indicated by reference numeral 18, the value in the memory section 17 of the torque correction word 16, and the value in the memory section 28 of the acceleration/deceleration word. The chopper circuit 1 is operated by this output word 13, a voltage corresponding to the output word 13 is applied to the motor 2, and the speed of the motor 2 is controlled.

The above series of operations will be explained according to the flowchart shown in FIG. First, the memory section 17 of the torque correction word 16 and the memory sections 25 and 26 of the speed word 15 are cleared (initial value=0). Next, the command word 10 (V _o ) set by the keyboard 6 is read. Then, the rotation speed of the electric motor 2 is detected, and the speed word 15 is detected.
(V _fo ), 12 deviation words E=V _o −V _fo
Perform the calculation. Next, depending on the size of this deviation word E, that is, 22 to 24 depending on whether E is negative, greater than L ₃ , greater than L ₂ , or greater than L ₁ .
Select one of the values of the constant words K ₁ , K ₂ , and K ₃ for correction. Then, the 16 torque correction words J _o = J _o-1 ±
Calculate K _o . Next, in order to determine 27 acceleration/deceleration words M, ΔV _f =V _{fo -1} −V _fo is calculated.
When ΔV _f = 0, it is a steady speed, M = 0, Δ _f = 0
When , it is deceleration, and when M=+P, it is acceleration, and when ΔV _f <0, it is assumed that M=-P. And 13 output words
Calculate OUT=G×E+J _o +M. here,
G is a proportional constant word of 18. By outputting an output word OUT indicated by reference numeral 13, the chopper circuit 1 is driven and the speed of the electric motor 2 is controlled.

By performing such control, a constant speed can be maintained even if the load fluctuates, and the acceleration/deceleration word 27 acts to suppress acceleration and deceleration, thereby reducing pulsation during rotation.

〔Effect of the invention〕

As described above, the present invention includes an electric motor 2, a chopper circuit 1 that drives the electric motor 2, an encoder 3 that detects the speed of the electric motor 2, a counter 4 that processes the output signal of this encoder, and a chopper circuit 1 that drives the electric motor 2. a keyboard 6 for giving commands;
An input/output device 7 including an output word 13, a speed word 15, and a command word 10, and this input/output device 7 and a memory 9.
Interposed between the output calculation unit 14 and the torque correction word 1
6, an arithmetic device 8 including an acceleration/deceleration word 27 and a deviation word 12, a memory section 11, 17, 25, 26, 28 for storing data from this arithmetic device 8, and a memory including a plurality of constant words 18 to 24; 9, the current portion of the speed word 15 given at any time by the counter 4 is stored in the memory section 25, and the previous portion is stored in the memory section 26.
Calculated from the difference between the memory units 25 and 26 that store the speed words 15 in chronological order such that the previous time is transferred from the memory unit 25 to the memory unit 26, and the speed words 15 stored in these memory units 25 and 26. A memory section 28 stores an acceleration/deceleration word 27 that is a negative value during acceleration and a positive value during deceleration, and the arithmetic unit 8 stores the motor speed command word 10 and the motor speed word 15 given by the keyboard 6. , calculate the deviation word 12 from the difference, select one of the constant words 19, 20, and 21 of the area according to the size of the deviation word 12, and select one of the selected constant words. Select one of the correction constant words 22, 23, and 24 corresponding to the correction constant word, correct the previous torque correction word 16 with the selected one correction constant word, and store the latest torque correction word 16. 17, an output word 13 obtained by adding the deviation word 12 multiplied by the proportionality constant word 18, the torque correction word 16, and the acceleration/deceleration word 27 by the output calculation unit 14; Since the chopper circuit 1 that drives the electric motor 2 is controlled according to the output word 13, the correction word is selected according to the deviation between the command word and the speed word, so that the load can be reduced. Even if it changes,
With this correction word, the rotation speed of the motor can be kept constant, and the speed word of the motor can be stored in chronological order.
This distinguishes between acceleration and deceleration, and reduces the output (-P) when accelerating and increases the output (+P) when decelerating, so the rotation speed of the motor can be held constant in the same way, and the rotation of the motor This has the effect of reducing pulsation and increasing high-speed response.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a diagram showing an operation flow, FIG. 3 is an explanatory diagram of a correction method according to deviation words, and FIG. 4 is a diagram showing the relationship between acceleration/deceleration words and speed words. DESCRIPTION OF SYMBOLS 1... Chopper circuit, 2... Electric motor, 3... Encoder, 4... Counter, 5... Latch register, 6... Keyboard, 7... Input/output device, 8...
...Arithmetic unit, 9...Memory, 10...Command word, 1
1...Memory part of command word, 12...Deviation word, 13
...Output word, 14...Output calculation section, 15...Speed word, 16...Torque correction word, 17...Torque correction word memory section, 18...Proportionality constant word, 19,2
0, 21... area constant word, 22, 23, 24...
... Correction constant word, 25, 26... Memory section for time series speed words, 27... Acceleration/deceleration word, 28... Memory section for acceleration/deceleration word.

Claims (1)

[Claims] 1. An electric motor 2, a chopper circuit 1 that drives the electric motor 2, an encoder 3 that detects the speed of the electric motor 2, a counter 4 that processes the output signal of this encoder, and a speed command for the electric motor 2. keyboard 6, output word 13, speed word 1
5, an input/output device 7 including a command word 10, and an operation interposed between the input/output device 7 and the memory 9, including an output calculation section 14, a torque correction word 16, an acceleration/deceleration word 27, and a deviation word 12. A device 8 and a memory section 11, 1 that stores data generated by the arithmetic device 8.
7, 25, 26, 28 and a memory 9 containing a plurality of constant words 18 to 24, the present speed word 15 given by the counter 4 at any time is stored in the memory section 25, and the previous speed word is stored in the memory section 26.
Calculated from the difference between the memory units 25 and 26 that store the speed words 15 in chronological order such that the previous time is transferred from the memory unit 25 to the memory unit 26, and the speed words 15 stored in these memory units 25 and 26. A memory section 28 stores an acceleration/deceleration word 27 that is a negative value during acceleration and a positive value during deceleration, and the arithmetic unit 8 stores the motor speed command word 10 and the motor speed word 15 given by the keyboard 6. , calculate the deviation word 12 from the difference, select one of the constant words 19, 20, and 21 of the area according to the size of the deviation word 12, and select one of the selected constant words. Select one of the correction constant words 22, 23, and 24 corresponding to the correction constant word, correct the previous torque correction word 16 with the selected one correction constant word, and store the latest torque correction word 16. 17, an output word 13 obtained by adding the deviation word 12 multiplied by the proportional constant word 18, the torque correction word 16, and the acceleration/deceleration word 27 by the output calculation unit 14; A speed control device for an electric motor, characterized in that the chopper circuit 1 for driving the electric motor 2 is controlled in accordance with the output word 13.