TW201539163A - Feedback control method, feedback control apparatus and program - Google Patents

Abstract

To implement high-accuracy position control without using a speed feedback control mechanism. A feedback control method for performing an operation on the basis of a deviation between a target position signal and a position detection signal to acquire a first operation result, controlling a power part by a control amount corresponding to the first operation result to perform position control of an object to be controlled, and regarding, as the position detection signal, a detection signal at the position of the object to be controlled obtained by the position control, wherein when the absolute value of the deviation is within a preset threshold, an integral operation is performed on the basis of the deviation to acquire an integral operation result, and the integral operation result is added to the first operation result to find the control amount.

Description

Feedback control method, feedback control device and program

The present invention relates to a feedback control method, a feedback control device, and a program for performing alignment of a control object.

Fig. 3 discloses an edge position control device for aligning edge positions of a web 10 transported in the A direction, and Fig. 4 discloses a functional block diagram of a feedback control device used in the edge position control device. The paper roll 10 is supplied with a predetermined tension and is conveyed in the A direction by the roller 20, and the edge position during transportation is detected by the position detector 30 and extracted to the control amplifier 40A. In the control amplifier 40A, the edge position set as the target is set in advance, and a control signal (speed command signal) is generated in the control amplifier 40A, and the control signal corresponds to the target position signal of the target edge and the actual edge. The position detection signal is deviated. By the control signal, the power unit (DC motor) 50 is driven, and the angle of the guide roller 60 directly coupled to the power unit 50 with respect to the paper roll 10 is changed. Thereby, the paper roll 10 moves in a direction orthogonal to the conveyance direction A. As described above, the control for making the edge position the target position is performed.

The control amplifier 40A is provided with a proportional calculator, and performs a proportional calculation (P calculus) on the deviation of the edge target position signal from the position detection signal according to the predetermined gain; or has a point calculator in addition to the proportional calculator, and performs the past Since the deviation of each sample is the integral calculus of the integral (I calculus); or the differential calculus is added in addition to the proportional calculus and the integral calculator, and the differential calculus proportional to the increase tendency of the deviation or the tendency of the decrease tendency is performed. (D calculus). Most of the general control devices use such a configuration, but many of the edge position detections use only the P calculation. In addition, there are also calculation methods other than P calculus or PID calculus.

FIG. 5 shows an internal configuration of an example of the control amplifier 40A. The position detection signal detected by the position detector 30 is converted into a signal of the same type as the target position signal by the signal converter 43, but when the noise is large, the switch SW1 is switched to the dotted line side in advance. Thereby, the noise is removed by the low pass filter 41, and then input to the signal converter 43. The target position signal of the edge is subtracted from the position detection signal output from the signal converter 43 by the subtractor 44 to become a deviation signal. The deviation signal is scaled by the proportional calculator 45 set to gain, and then output to the power unit 50 as a speed command signal. However, in the case of the deviation signal, when the noise is large, the switch SW2 is switched to the dotted line side in advance, thereby being input to the proportional calculator 45 via the low-pass filter 42 and then calculated. Further, when the signal output from the control amplifier 40A is set as the target position signal, the integral calculator is added in parallel to the proportional calculator 45.

The DC motor is used in the power unit 50, but a hydraulic device may also be used. Here, an example using a DC motor will be described. The power unit 50 is driven by a speed command signal (actually mostly driving the voltage or power of the DC motor) output from the control amplifier 40A. The control amplifier used in general edge position control is a built-in power amplifier that drives a DC motor, and the edge position of the paper roll 10 pushed by the power unit 50 is used as an output transfer function, which is approximated. Integral (position = speed × time). That is to say, since the power unit 50 has an integral characteristic, even when the control amplifier 40A has only the simple proportional calculator 45, good control characteristics can be obtained.

As the position detector 30, a photodetector that directly detects the edge position of the paper roll 10 or a line sensor that detects the position of the line printed on the paper roll 10 or the like is used.

By providing the feedback control device that performs the above-described control as described above, it is theoretically possible to constitute an edge position control device which is inexpensive and has good control characteristics.

However, in reality, when the amount of control of the edge position is small, the DC motor or the hydraulic device of the power unit 50 may not be sufficiently operated due to manufacturing factors, friction due to changes in years, and the like. That is to say, the control characteristics at the time of minute deviation may be deteriorated, and the state of leaving a small deviation may be obtained. This tendency is particularly strong in the case of using a DC motor.

In view of this, sometimes the power unit 50 shown in Figure 4 will be as shown in the figure. 6 is replaced with a power unit 50A which is provided with a servo controller 52 and an encoder 53 for detecting the rotation of the DC motor 51 in addition to the DC motor 51, and performs speed feedback control at the power unit 50A. . In this way, the speed parameter of the servo controller 52 is set so that it can operate reliably even with a slight deviation, whereby a highly accurate position control system can be constructed.

Further, Patent Document 1 describes a model following control method for improving control accuracy when positioning is performed by a motor control device. The model follows the control method and constructs a model control system that simulates the actual feedback control system and drives the feedback control system to follow the model control system.

Prior technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2010-51104

However, the method of using the power unit 50A illustrated in Fig. 6 requires the servo controller 52 or the encoder 53, which has the disadvantage of an increase in price. Further, the technique described in Patent Document 1 introduces model control in addition to the multiple feedback control mechanism, and thus becomes a very expensive system, and parameter adjustment depends on expertise.

An object of the present invention is to provide a high-precision position control even if a speed feedback control mechanism is not used in the power unit. Feedback control method, feedback control device, and program.

In order to achieve the above object, the feedback control method of the invention of claim 1 is based on the deviation between the target position signal and the position detection signal to obtain the first calculation result, and the control corresponding to the first calculation result is controlled. The amount of the power unit is controlled to control the position of the control object, and the detection signal of the position of the control object obtained by the position control is used as the position detection signal. The feedback control method is characterized in that: When the value falls within the threshold value set in advance, the integral calculation is performed based on the deviation, and the integral calculation result is obtained, and the integration calculation result is added to the first calculation result as the control amount.

The invention of claim 2 is the feedback control method described in claim 1, wherein when the deviation is zero or can be regarded as a value of zero, the result of the aforementioned integral calculation is reset to zero.

The invention of claim 3 is the feedback control method described in claim 1 or 2, wherein when the deviation is zero or can be regarded as a value of zero, the integral calculation is stopped and The result of the integral calculation is reset to zero.

The feedback control device of the invention of claim 3, comprising: a subtractor that subtracts the position detection signal from the target position signal to calculate the deviation; and the first calculator performs the deviation according to the subtractor Calculation; and the power department, by and with the first calculator The first calculation result arrives at a position control corresponding to the control object; and the position detector detects the position of the control object controlled by the power unit; and detects the signal detected by the position detector As the position detection signal, the feedback control device is characterized in that: the integral calculator is provided, and when the absolute value of the deviation falls within a predetermined threshold, the integral calculation is performed according to the deviation, and the integral calculation is obtained. The result of the integral calculation is added to the first calculation result as the aforementioned control amount.

The invention of claim 5 is the feedback control device according to claim 4, wherein the integral calculator has the aforementioned integral points when the deviation is zero or can be regarded as a value of zero. The result of the calculation is reset to zero.

The invention of claim 6 is the feedback control device according to claim 4, wherein the integral calculator stops the integral calculation and the points so far when the deviation exceeds the threshold The result is reset to zero.

The program of the invention of claim 7 is for causing the computer to perform the following feedback control method, that is, calculating the deviation based on the deviation between the target position signal and the position detection signal, thereby obtaining the first calculation result by using the first calculation result The control unit controls the power unit to control the position of the control object, and the detection signal of the position of the control target obtained by the position control is used as the position detection signal. The program is characterized in that: In the first step, it is determined whether the absolute value of the deviation falls within a threshold set in advance; and the second step is performed by the first step When it is determined that the absolute value of the deviation falls within the threshold value, the integral calculation is performed based on the deviation, and the integration calculation result is added to the first calculation result as the control amount.

The invention of claim 8 is the program according to claim 7, wherein the third step is to determine, by the first step, that the absolute value of the deviation falls within the threshold, and the foregoing When the deviation is zero or can be regarded as a value of zero, the aforementioned integral calculation result until now is reset to zero.

The invention of claim 9 is the program according to claim 7 or 8, wherein the method of claim 7 includes: in the fourth step, determining, by the first step, that the absolute value of the deviation does not fall within the threshold At this time, the aforementioned integral calculation is stopped and the result of the integral calculation so far is reset to zero.

According to the inventions of claims 1, 4, and 7, when the absolute value of the deviation falls within the threshold, the integral calculation of the deviation is performed, and the integral calculation result is added to the first calculation result to obtain the control amount, so even The deviation is small, and it can be made zero, which can improve the control accuracy. Further, according to the inventions of the second, fifth, and eighth inventions, when the deviation is zero or can be regarded as zero, the integral value so far is zero reset, so that overshoot can be prevented ( Overshoot). Further, in addition, according to the inventions of claims 3, 6, and 9, when the absolute value of the deviation exceeds the threshold, the integral calculation is stopped and the integral value up to now is The zero reset is performed, so that the instability that occurs when the power portion has an integral characteristic can be suppressed.

10‧‧‧ paper rolls

20‧‧‧roll

30‧‧‧ position detector

40,40A‧‧‧Control amplifier

41, 42‧‧‧ low pass filter

43‧‧‧Signal Converter

44‧‧‧Subtractor

45‧‧‧Proportional Calculator

46‧‧‧Integral Calculator

47‧‧‧Adder

50, 50A‧‧ Power Department

51‧‧‧DC motor

52‧‧‧Servo Controller

53‧‧‧Encoder

60‧‧‧ Guide roller

Fig. 1 is a schematic block diagram showing the configuration of a control amplifier of a feedback control device according to an embodiment of the present invention.

[Fig. 2] An operation flow chart of the integral calculator of the control amplifier of Fig. 1.

[Fig. 3] A schematic view showing the configuration of an edge position control device for controlling the edge position of the paper roll.

Fig. 4 is a functional block diagram of a feedback control device used in the edge position control device of Fig. 3.

Fig. 5 is a schematic block diagram showing the configuration of a control amplifier of the feedback control device of Fig. 4.

Fig. 6 is a functional block diagram of a feedback control device of another example used in the edge position control device of Fig. 3.

In the feedback control, in order to make the small deviation of the recurring residual zero, an effective method is to use the integral calculus as the control calculus. However, if the integral calculation is introduced, there is a problem that the phase of the control output is delayed by 90 degrees. In the position control, the power unit itself has integral characteristics as described above, so if the integral is used in the control calculation, the stability of the control system will be achieved. Significantly degraded.

In view of the above, in the present invention, it is designed such that the integral calculation is performed only when there is a slight deviation within a predetermined threshold set in advance so as not to impair the stability of the control system, and the deviation becomes zero. In addition, in order to reduce the overshoot, when the deviation reaches zero or is regarded as a value of zero, the integral value is reset to zero. Further, since the power unit usually has an integral characteristic, this can be utilized. Therefore, as long as the deviation becomes larger than the threshold value, the integral calculation is stopped and the integral value is reset to zero.

Figure 1 discloses a control amplifier 40 in accordance with one embodiment of the present invention. In the control amplifier 40, the edge position control device described with reference to Figs. 3 and 4 is replaced with a control amplifier 40A. In FIG. 1, the control amplifier 40 of the present embodiment includes a low pass filter 41, 42 and a signal converter 43 for converting the position detection signal of the edge into a signal of the same type as the target position signal, a subtractor 44, and a proportional calculator. 45. Ategral calculator 46, adder 47, switches SW1, SW2, SW3.

The position detection signal detected by the position detector 30 is input to the signal converter 43 via the switch SW1, but when the noise is large, the switch SW1 is switched to the dotted line side in advance, thereby using a low-pass filter. After the noise is suppressed by 41, it is input to the signal converter 43 again. The position detection signal input to the signal converter 43 is converted into a signal of the same kind as the target position signal and output. The subtracter 44 subtracts the position detection signal from the input target position signal, thereby generating a deviation signal. The deviation signal is input to the proportional calculator 45 via the switch SW2. When the noise is large, the deviation signal will switch the switch SW2 to the side of the dotted line in advance, thereby The low pass filter 42 suppresses the noise and then inputs it to the scale calculator 45. Further, when the switch SW3 is ON, it is also input to the integral calculator 46. The respective calculation results of the scale calculator 45 and the integral calculator 46 are added to the adder 47 and input as a speed command signal.

The switch SW3 is turned ON when the absolute value of the deviation is within a predetermined threshold, and is turned OFF when the threshold is exceeded. At this OFF, the integral calculator 46 stops the integral calculation and resets the integral value so far to zero. Further, the integral calculator 46 resets the integral value so far when the deviation becomes zero (crossing with the zero point) or becomes small to be visible to zero.

There are two ways to set the threshold. One type is a method of matching the characteristics of the DC motor used in the power unit 50, and the other is a method of roughly setting it. In the former case, when the integral time constant of the integral element in the DC motor is large, the value is set small, and when the constant hour is set large. In the latter case, it is preferable to set the size of the control precision + α to be preferable. When the threshold is increased, the stability of the control system may be deteriorated, so it is desirable to set the size to the minimum necessary. As long as the appropriate threshold is preset as the initial set value, no fine parameter adjustment is required in most of the position control.

2 shows a flow chart of the control routine of switch SW3 and integral calculator 46. In order to realize the processing of the control amplifier 40 of the present embodiment, a digital calculation device using a computer such as a microprocessor or an FPGA is used. Therefore, the processing of FIG. 2 is performed for each sample of the deviation obtained by the subtractor 44.

First, it is determined whether or not the absolute value of the sampled deviation is within the threshold (step S1). When the absolute value of the deviation is within the threshold, it is determined whether the deviation is zero (step S2). At this time, in the case where the deviation is zero or can be regarded as zero, the integrated value obtained by the sampling up to the previous time in the integral calculator 46 is reset by the zero position (step S3). At this time, the switch SW3 can be turned ON or OFF. Further, when the deviation is not zero or can not be regarded as zero, the switch SW3 is turned ON, and the deviation is calculated by the integral (step S4). Then, when integrating by the integral calculator 46 as such, the integral calculation result is added by the proportional calculation result by the scaler 47 by the adder 47 (step 5). On the other hand, when the absolute value of the deviation is out of the threshold range in step S1, the switch SW3 is turned off, and the integral value of the integral calculator 46 up to the present is reset by the zero position. When the deviation from the next sampling is taken, the same processing as above is repeated depending on the absolute value of the deviation.

By performing such control, even if the deviation is small, the power necessary to start the DC motor can be supplied to the power unit 50. When the absolute value of the deviation is out of the threshold range, the integral calculation is not performed. Therefore, the integral operation at this time is performed only in the power unit 50, and the instability of the control can be avoided. In addition, when the deviation is zero, the integral value so far is reset by the zero position, so that no unnecessary correction operation is performed. The parameters in the proportional calculator 45 or the integral calculator 46 are determined while observing the control characteristics, and thus can be easily set for the user.

Further, the means for correcting the edge position of the paper roll 10 is not limited to the guide roller 60, and the rewinding reel (rewind) for the paper roll 10 can also be used. Reel) or a mechanism in which the reel is moved in the axial direction.

Further, although the above description has been made on the case where the feedback control device for controlling the edge position of the paper roll is used, the power unit and the control object are not directly connected, but the present invention is not limited thereto, and even if it is applied to the power unit and the control object directly When position control is performed by other feedback control in the case of connection, high control accuracy can be achieved at a low price in the same manner. In addition, the integral calculation described above also includes other calculus similar to integrals such as pulse transfer function calculus and linear difference equation calculus. Further, as the feedback control, it is possible to employ a robust control in which the modeling error is also taken into consideration, or an adaptive control in which the parameter changes in response to a large fluctuation of the control object.

40‧‧‧Control amplifier

41, 42‧‧‧ low-pass filter

43‧‧‧Signal Converter

44‧‧‧Subtractor

45‧‧‧Proportional Calculator

46‧‧‧Integral Calculator

47‧‧‧Adder

SW1, SW2, SW3‧‧‧ switch

Claims (9)

A feedback control method is performed by calculating a deviation from a target position signal and a position detection signal to obtain a first calculation result, and controlling a power unit by a control amount corresponding to the first calculation result to perform position control on the control target, The detection signal of the position of the control object obtained by the position control is used as the position detection signal, and the feedback control method is characterized in that when the absolute value of the deviation falls within a predetermined threshold, according to the foregoing The integration calculation is performed to obtain the integral calculation result, and the integration calculation result is added to the first calculation result as the control amount. The feedback control method according to claim 1, wherein when the deviation is zero or can be regarded as a value of zero, the aforementioned integral calculation result is reset to zero. The feedback control method according to claim 1 or 2, wherein, when the deviation exceeds the threshold, the integral calculation is stopped and the result of the integration calculation to date is reset to zero. A feedback control device includes: a subtractor that subtracts a position detection signal from a target position signal to calculate a deviation; and a first calculator that performs calculation based on the deviation obtained by the subtractor; and a power unit Positioning the control object with a control amount corresponding to the first calculation result obtained by the first calculator; and detecting a position of the control object subjected to position control by the power unit; position The signal detected by the detector is used as the position detection signal, and the feedback control device is characterized in that: the integral calculator is set, and when the absolute value of the deviation falls within a preset threshold, the integral calculation is performed according to the deviation, The integral calculation result obtained by the integral calculator is added to the first calculation result as the control amount. The feedback control device according to claim 4, wherein the integral calculator resets the previous integration result to zero when the deviation is zero or can be regarded as a value of zero. The feedback control device according to claim 4, wherein the integral calculator stops the integral calculation and resets the integration result to zero until the deviation exceeds the threshold. A program for causing a computer to perform a feedback control method of calculating a first calculation result based on a deviation between a target position signal and a position detection signal, and controlling by a control amount corresponding to the first calculation result The power unit performs position control on the control target, and the detection signal of the position of the control target obtained by the position control is used as the position detection signal, and the program includes the first step of determining the deviation. Whether the absolute value falls within a predetermined threshold; and in the second step, when it is determined by the first step that the absolute value of the deviation falls within the threshold, the integral calculation is performed based on the deviation The result of the integral calculation is added to the first calculation result as the aforementioned control amount. The program according to claim 7, wherein the third step is to determine, by the first step, that the absolute value of the deviation falls within the threshold, and the deviation is zero or can be regarded as zero At the time of the value, the aforementioned integral calculation result until now is reset to zero. The program according to claim 7 or 8, wherein the fourth step includes: when determining, by the first step, that the absolute value of the deviation does not fall within the threshold, stopping the integral calculation and The result of the integral calculation so far is reset to zero.