Identification method and identification unit for time delay model, and color registration system for intaglio printing press

Abstract

Embodiments of the present application provide a time delay model identification method, an identification unit and a gravure printing machine color matching system. The method comprises: recording a step response time domain curve of a color mark difference value of a material detected by a color mark sensor output; fitting a first-order inertia system mathematical model based on a least square method to the step response time domain curve of the color mark difference value to obtain a time delay model of the gravure printing machine color matching system. Embodiments of the present application can accurately and automatically identify the time delay model of the system, and ensure the color matching accuracy of the gravure printing machine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gravure printing machines and color registration technology, and in particular to a time delay model identification method for a color registration system of a gravure printing machine, an identification unit and a color registration system of a gravure printing machine. BACKGROUND

[0002] A gravure printing machine is prone to material deformation due to its process characteristics. In order to ensure the color registration accuracy of a product, a color registration system is usually needed. The color registration adjustment algorithm of the color registration system generally relies on a hysteresis model, that is, the output can change synchronously with the input only after a certain lag time. However, there is no accurate automatic identification method for the hysteresis model in the prior art. SUMMARY

[0003] In view of this, the present application provides a time delay model identification method, an identification unit and a color registration system of a gravure printing machine, which are used to at least partially solve the above technical problems.

[0004] In a first aspect, the present application provides a time delay model identification method for a color registration system of a gravure printing machine, comprising:

[0005] recording a step response time domain curve of a color difference value of a material detected by a color mark sensor output;

[0006] fitting a mathematical model of a first-order inertial system to the step response time domain curve of the color difference value based on a least squares method to obtain a time delay model of the color registration system of the gravure printing machine.

[0007] In a possible implementation, before the step response time domain curve of the color difference value of the material detected by the color mark sensor output is recorded, the color difference value of the material detected by the color mark sensor output is further subjected to a low-pass filtering process.

[0008] In a possible implementation, after the mathematical model of the first-order inertial system is fitted to the step response time domain curve of the color difference value based on the least squares method to obtain the time delay model of the color registration system of the gravure printing machine, the method further comprises:

[0009] calculating at least one set of characteristic values of the time delay model of the color registration system of the gravure printing machine;

[0010] comparing and verifying the at least one set of characteristic values with the step response time domain curve of the color difference value respectively, and saving the time delay model of the color registration system of the gravure printing machine if the verification is passed;

[0011] In a possible implementation, the mathematical model of the first-order inertia system is y=A(1-e^(-t / T)), where A is a proportional coefficient and T is a time constant; and the at least one set of characteristic values includes one or more of the following sets: (T, 0.632*A); (2*T, 0.865*A); (3*T, 0.95*A).

[0012] In a possible implementation, the model identification unit further includes a recording module, configured to record a step response time-domain curve of a color difference value of a material detected by a color sensor.

[0013] The motor drives the material to perform a corresponding superimposed motion in response to a superimposed displacement adjustment amount input of the step.

[0014] The color sensor detects a color of the material performing the superimposed motion, calculates a color difference value, and outputs the color difference value.

[0015] In a second aspect, the present application further provides a time delay model identification unit for a gravure press color matching system, characterized in that the unit includes:

[0016] a recording module, configured to record a step response time-domain curve of a color difference value of a material detected by a color sensor.

[0017] a fitting module, configured to fit a mathematical model of a first-order inertia system to the step response time-domain curve of the color difference value based on a least square method, to obtain a time delay model of the gravure press color matching system.

[0018] In a possible implementation, the model identification unit further includes a filtering module, configured to perform low-pass filtering processing on a color difference value of a material detected by a color sensor, and the recording module is further configured to record a step response time-domain curve of the filtered color difference value.

[0019] In a possible implementation, the model identification unit further includes a verification module, configured to calculate at least one set of characteristic values of the time delay model of the gravure press color matching system, and compare the at least one set of characteristic values with the step response time-domain curve of the color difference value respectively, and if the comparison passes, save the time delay model of the gravure press color matching system, where the mathematical model of the first-order inertia system is y=A(1-e^(-t / T)), A is a proportional coefficient and T is a time constant, and the at least one set of characteristic values includes one or more of the following sets: (T, 0.632*A); (2*T, 0.865*A); (3*T, 0.95*A).

[0020] In a possible implementation, the filtering module and the recording module are executed in isochronous synchronous cycles, and the fitting module and the checking module are executed once in a predetermined execution priority by invocation.

[0021] In a third aspect, the present application further provides a gravure press color registration system, characterized in that comprising:

[0022] a motor configured to drive a material to perform a corresponding superimposed motion in response to a step input of a superimposed displacement adjustment amount;

[0023] a color mark sensor configured to detect a color mark of the material performing the superimposed motion, calculate a color mark difference value, and output the color mark difference value;

[0024] a controller comprising the aforementioned identification unit for the time delay model of the gravure press color registration system.

[0025] In a fourth aspect, the present application further provides a gravure press color registration system, characterized in that comprising:

[0026] a motor configured to drive a material to perform a corresponding superimposed motion in response to a step input of a superimposed displacement adjustment amount;

[0027] a color mark sensor configured to detect a color mark of the material performing the superimposed motion, calculate a color mark difference value, and output the color mark difference value;

[0028] a controller configured with a time delay model of the gravure press color registration system, and the controller is configured to calculate a displacement adjustment amount of the motor based on the time delay model of the gravure press color registration system according to the color mark difference value received from the color mark sensor, and adjust the displacement of the motor based on the calculated displacement adjustment amount, wherein the time delay model of the gravure press color registration system is identified according to the aforementioned identification method for the time delay model of the gravure press color registration system.

[0029] Compared with the prior art, the embodiments of the present invention have at least the following advantages: Recording the color mark difference values ​​of the detected material output by the color mark sensor to obtain a complete step response time-domain curve, and then fitting a first-order inertial system mathematical model to the complete step response time-domain curve using the least squares method. The fitted model has high accuracy, and the overall identification process is automatic, thus ensuring the registration accuracy of the gravure printing press for colors. Furthermore, the model identification accuracy can be further guaranteed by verifying the model through eigenvalues. Moreover, low-pass filtering of the color mark difference values ​​received from the color mark sensor before recording the step response time-domain curve of the color mark difference values ​​removes high-frequency fluctuations, further ensuring the model identification accuracy. In addition, since the overall identification process is automatic, the monitoring function of the controller configuration software is not required. Furthermore, the filtering and recording functional modules are synchronously executed periodically in the controller, while the fitting and verification functional modules are executed in the controller with a lower execution priority, minimizing the impact on the main program. Attached Figure Description

[0030] Figure 1 This is a flowchart of a method for identifying a time delay model for a color matching system of a gravure printing press, according to an embodiment of the invention.

[0031] Figure 2 This is a schematic diagram of the structure of an identification unit for a time delay model of a color matching system for a gravure printing press, according to an embodiment of the invention.

[0032] Figure 3 This is a schematic diagram of the color matching system of a gravure printing machine.

[0033] Figure 4 This is a schematic diagram of a time delay model according to an embodiment of the invention.

[0034] List of reference numerals in the attached diagram:

[0035] 201: Filtering Module

[0036] 202: Recording Module

[0037] 203: Fitting Module

[0038] 204: Verification Module

[0039] 301: Motor

[0040] 302: Color mark sensor

[0041] 303: Controller

[0042] 304: Color Code Detailed Implementation

[0043] For the purpose of making the present application, technical solutions, and advantages more clear, further detailed description is made to the present application with reference to the accompanying drawings and examples. Obviously, the described examples are only a part of the examples of the present application, but not all the examples. Based on the examples in the present application, all other technical solutions obtained by those skilled in the art belong to the scope of protection of the present application.

[0044] Figure 1 A flow chart of the identification method of the time delay model of the gravure printing machine color registration system according to an embodiment of the present application is shown. As shown in the figure, the method comprises: Figure 1

[0045] Step S104: record the step response time domain curve of the color difference value of the material detected by the color mark sensor.

[0046] Specifically, the material in step S104 performs superimposed motion based on the driving force generated by the motor in response to the superimposed displacement adjustment amount input, and the color mark sensor detects the color mark of the material performing the superimposed motion and calculates and outputs the color difference value. For example, step S104 can be further implemented as steps S104a-S104c: S104a, the motor drives the material to perform corresponding superimposed motion in response to the superimposed displacement adjustment amount input, for example, the motor is running at a predetermined speed before the superimposed displacement adjustment amount input; S104a, the color mark sensor detects the color mark of the material performing the superimposed motion and calculates and outputs the color difference value to the controller; S104a, the controller records the step response time domain curve of the color difference value of the material detected by the color mark sensor.

[0047] Considering that the measurement signal of the color mark sensor usually has high frequency fluctuations, the present embodiment can optionally further comprise a filtering step S102 (as shown in the figure Figure 1 ) before step S104: receive the color difference value of the material detected by the color mark sensor, and perform low-pass filtering processing on the color difference value. And step S104 is further implemented as "record the step response time domain curve of the low-pass filtered color difference value". The low-pass filtering processing can filter out high frequency fluctuations to ensure accurate data acquisition. And the foregoing step S102 and the foregoing step S104 are preferably performed with isochronous synchronization period.

[0048] Step S106: based on the least square method, fit the mathematical model of the first-order inertia system to the step response time domain curve of the color difference value, to obtain the time delay model of the gravure printing machine color registration system. Specifically, the mathematical model of the first-order inertia system is expressed as where A is the proportional coefficient, and T is the time constant. ​

[0049] Optionally, step S106 is followed by a verification step S108 (as shown in Figure 1 ): first, at least one set of eigenvalues of the time delay model of the gravure press color matching system is calculated; then, the at least one set of eigenvalues is compared with the step response time domain curve of the color difference value respectively, and if the verification is passed, the time delay model of the gravure press color matching system is saved, and the present verification step verifies the model by eigenvalues, which can ensure the accuracy of model identification. In fact, step S106 can fit the specific values of the proportional coefficient A and the time constant T, which can be accurate to many decimal places, and the specific number of decimal places is related to the calculation accuracy of the system being fitted. Then, the at least one set of eigenvalues can include one or more of the following sets: (T, 0.632*A); (2*T, 0.865*A); (3*T, 0.95*A), and the specific eigenvalues participating in the comparison verification can be obtained by bringing in the proportional coefficient A and the time constant T fitted (as shown in Figure 4 for an example eigenvalue fitting result), and the specific eigenvalues are compared with the step response time domain curve of the color difference value respectively, and if the comparison result is within a predetermined deviation range, the verification is passed, otherwise, the verification is not passed. If not passed, for example, it can return to step S102.

[0050] Corresponding to the identification method embodiment of the time delay model of the gravure press color matching system, the present application also proposes an identification unit embodiment (as shown in Figure 2 ) for the time delay model of the gravure press color matching system and a gravure press color matching system embodiment (as shown in Figure 3 ), and it should be pointed out that since the following embodiments are to realize the foregoing method embodiments, the modules in the embodiments are all to realize the steps of the foregoing method, but the present application is not limited to the following embodiments, and any device and module that can realize the foregoing method should be within the protection scope of the present application, and in the following description, the same content as the foregoing method part is omitted here to save space.

[0051] Turning to Figure 2 , which shows a structure schematic diagram of an identification unit for the time delay model of the gravure press color matching system according to an embodiment of the present application. As shown in Figure 2 , the identification unit includes a recording module 202 and a fitting module 203. Specifically, the recording module 202 is used to record the step response time domain curve of the color difference value of the material detected by the color sensor 302. And, optionally, as shown in Figure 2As shown, the identification unit of the time-delay model may further include a filtering module 201. The filtering module 201 is used to perform low-pass filtering on the color mark difference value of the detected material received from the color mark sensor 302, and the recording module 202 is also used to record the step response time-domain curve of the low-pass filtered color mark difference value. Further, the filtering module 201 and the recording module 202 are preferably executed in the controller 303 with an isochronous synchronization period.

[0052] The fitting module 203 is used to fit a first-order inertial system mathematical model to the step response time-domain curve of the color mark difference based on the least squares method, thereby obtaining the time delay model of the gravure printing press color matching system. Furthermore, the fitting module 203 is also used to fit a first-order inertial system mathematical model to the filtered step response time-domain curve of the color mark difference based on the least squares method, thereby obtaining the time delay model of the gravure printing press color matching system.

[0053] Optionally, such as Figure 2 As shown, the identification unit of the time-delay model may further include a verification module 204. The verification module 204 is used to calculate at least one set of characteristic values ​​of the time-delay model of the gravure printing press color matching system, and compare the at least one set of characteristic values ​​with the step response time-domain curve of the aforementioned color mark difference. If the verification passes, the time-delay model of the gravure printing press color matching system is saved. Specifically, the mathematical model of the first-order inertial system can be expressed as follows: Where A is the proportionality coefficient and T is the time constant, the fitting process performed by the fitting module 203 is the process of calculating the proportionality coefficient A and the time constant T, and the at least one set of feature values ​​includes one or more of the following: (T, 0.632*A); (2*T, 0.865*A); (3*T, 0.95*A). Furthermore, the fitting module 203 and the verification module 204 are preferably executed once at a predetermined execution priority through a calling method in the controller 303, so that each module does not occupy too much of the controller 303's operating resources and has minimal impact on the main program in the controller 303.

[0054] Transfer to Figure 3 The diagram shows a structural diagram of a gravure printing machine color matching system according to an embodiment of the present invention. The system includes a color mark sensor 302, a controller 303, and a motor 301. When the system is working, the color mark sensor 302 detects the color marks on the material and calculates the color mark difference, which is then input to the controller 303. The controller 303 uses a color matching adjustment algorithm to calculate the adjustment amount and adjusts the speed of the motor 301 to correct the system so that the patterns overlap.

[0055] Furthermore, in an alternative embodiment, the motor 301 is configured to respond to a step-based superimposed displacement adjustment input (e.g., Figure 4the curve I) to drive the current material to perform a corresponding superimposed motion, the color sensor 302 is configured to detect the color of the material and calculate and output the color difference value, and the controller 303 includes both the recording module 202 and the fitting module 203 of the identification unit embodiment of the aforementioned time delay model or any combination of the two and the filtering model and the verification module 204, to obtain the final time delay model of the gravure press color matching system (such as Figure 4 The curve O). Taking the PLC as the controller 303 as an example, after a step adjustment amount of the motor 301 is given, the error value of the color sensor 302 passes through the filtering module 201 and the recording module 202 at a fixed cycle period. The filtering module 201 and the recording module 202 need to ensure real-time performance and are placed in the PLC for execution in a time-synchronous cycle, for example but not limited to IPO TASK. The fitting module 203 and the verification module 204 are executed by calling a single execution with a lower execution priority in the PLC, for example, MOTION TASK, which can prevent the load rate from being too high during PLC operation, so as to ensure that too many PLC running resources are not occupied and the main program is less affected.

[0056] In another optional embodiment, the motor 301 is configured to drive the material to move, for example, to run at a predetermined running state (for example but not limited to uniform speed); wherein the color sensor 302 is configured to detect the color of the moving material and calculate and output the color difference value. And the controller 303 is configured with the time delay model obtained according to the aforementioned identification method embodiment of the time delay model, and the controller 303 is configured to calculate the displacement adjustment amount of the motor 301 based on the color difference value received from the color sensor 302 based on the configured time delay model and adjust the displacement of the motor 301 based on the calculated displacement adjustment amount, thereby correcting the system to make the pattern coincide.

[0057] And, the aforementioned two optional embodiments can be combined to constitute a gravure press color matching system of yet another optional embodiment.

[0058] It should be noted that in the claims and specification of the present patent, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "including one" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0059] It is apparent that those skilled in the art should understand that each module or each step of the above-mentioned embodiments of the present specification can be realized by a general computing device, which can be centralized on a single computing device or distributed on a network composed of multiple computing devices, and optionally, each module or each step can be realized by program codes executable by a computing device, so that each module or each step can be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described can be executed in different orders, or each module or each step can be manufactured as an individual integrated circuit module, or multiple modules or steps can be manufactured as a single integrated circuit module. Thus, the embodiments of the present specification are not limited to any specific combination of hardware and software.

[0060] Although the present application has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the present application.

[0061] The above has been detailed by the drawings and preferred embodiments, however, the present application is not limited to these disclosed embodiments, and those skilled in the art can know that more embodiments of the present application can be obtained by combining the code review means in the above different embodiments, and these embodiments are also within the protection scope of the present application.

Claims

1. A method for identifying a time delay model for a color registration system in a gravure printing press, characterized in that, Record the time-domain curve of the step response of the color mark sensor to the color mark difference of the detected material; The time-delay model of the gravure printing press color matching system is obtained by fitting the step response time-domain curve of the color mark difference to a first-order inertial system using the least squares method.

2. The method for identifying the time delay model of a color registration system in a gravure printing press according to claim 1, characterized in that, Before recording the step response time-domain curve of the color mark difference of the detected material output by the color mark sensor, the following is also included: The color mark difference value of the material detected by the color mark sensor is processed by low-pass filtering.

3. The method for identifying the time delay model of a color registration system in a gravure printing press according to claim 1, characterized in that, After fitting the time-domain curve of the step response of the color mark difference based on the least squares method to a mathematical model of a first-order inertial system to obtain the time-delay model of the color registration system of the gravure printing press, the method further includes: Calculate at least one set of characteristic values ​​for the time delay model of the color registration system of the gravure printing machine; The at least one set of feature values ​​are compared and verified with the step response time-domain curve of the color mark difference. If the verification passes, the time delay model of the gravure printing machine color matching system is saved. The mathematical model of the first-order inertial system is as follows: Where A is a proportionality coefficient and T is a time constant; and the at least one set of characteristic values ​​includes one or more of the following sets: (T, 0.632*A); (2*T, 0.865*A); (3*T, 0.95*A).

4. The method for identifying the time delay model of a color registration system for a gravure printing press according to any one of claims 1-3, characterized in that, Before recording the step response time-domain curve of the color mark difference of the detected material output by the color mark sensor, the following is also included: The motor responds to a step-based superimposed displacement adjustment input and drives the material to perform a corresponding superimposed motion; The color mark sensor detects the color mark of the material performing the superposition motion, calculates the color mark difference, and outputs the color mark difference.

5. A time-delay model identification unit for a color registration system in a gravure printing press, characterized in that, include: The recording module (202) is used to record the step response time-domain curve of the color mark difference of the material detected by the color mark sensor (302); The fitting module (203) is used to fit the mathematical model of the first-order inertial system to the step response time-domain curve of the color mark difference based on the least squares method, so as to obtain the time delay model of the color matching system of the gravure printing machine.

6. The identification unit for the time delay model of the color registration system of a gravure printing press according to claim 5, characterized in that, The identification unit of the time delay model further includes a filtering module (201), which is used to perform low-pass filtering on the color mark difference value of the material detected by the color mark sensor (302) and the recording module (202) is also used to record the step response time domain curve of the filtered color mark difference value.

7. The identification unit for the time delay model of the color registration system of a gravure printing press according to claim 5, characterized in that, The identification unit of the time delay model further includes a verification module (204). The verification module (204) is used to calculate at least one set of characteristic values ​​of the time delay model of the gravure printing press color matching system, and to compare and verify the at least one set of characteristic values ​​with the step response time-domain curve of the color mark difference. If the verification passes, the time delay model of the gravure printing press color matching system is saved. The mathematical model of the first-order inertial system is: Where A is a proportionality coefficient, T is a time constant, and the at least one set of characteristic values ​​includes one or more of the following sets: (T, 0.632*A); (2*T, 0.865*A); (3*T, 0.95*A).

8. The identification unit for the time delay model of the color registration system of a gravure printing press according to claim 6, characterized in that, The filtering module (201) and the recording module (202) are executed in a synchronous period.

9. The identification unit for the time delay model of the color matching system of a gravure printing press according to claim 7, characterized in that, The fitting module (203) and the verification module (204) are executed once at a predetermined execution priority by means of a call.

10. A color matching system for a gravure printing machine, characterized in that, include: Motor (301) is used to drive the current material to perform the corresponding superimposed motion in response to a step superimposed displacement adjustment input; A color mark sensor (302) is used to detect the color mark of the material performing the superposition motion, calculate the color mark difference, and output the color mark difference. The controller (303) includes an identification unit for the time delay model of the color matching system of a gravure printing press as described in any one of claims 5-9.

11. A color registration system for a gravure printing machine, characterized in that, include: Electric motor (301), used to drive the movement of materials; A color mark sensor (302) is used to detect the color mark of the current material, calculate the color mark difference, and output the color mark difference. A controller (303) is configured with a time delay model of a gravure printing machine color matching system, and the controller (303) is used to calculate the displacement adjustment amount of a motor (301) based on the time delay model of the gravure printing machine color matching system according to the color mark difference value received from the color mark sensor (302), and to adjust the displacement of the motor (301) based on the calculated displacement adjustment amount, wherein the time delay model of the gravure printing machine color matching system is identified by the time delay model identification method for the gravure printing machine color matching system according to any one of claims 1-4.

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