A double-integral plus feedforward based speed-up control method and device for a color registration system

Abstract

The application discloses a kind of based on double integral plus feedforward's system speed-up control method and equipment;Decoupling module is designed, and single-color group steady speed decoupling model is obtained;System speed-up open loop experiment is designed, and the acceleration feedforward compensation of single-color group is calculated according to the data of system speed-up open loop experiment and single-color group steady speed decoupling model;According to the steady speed decoupling model of single-color group under different operating speeds, a double integral controller is designed as a closed-loop controller, and the designed double integral controller can ensure the stability of the system during the speed-up process from the starting speed to the target speed;During the system speed-up control process of color matching system, the feedback of color matching error sensor at each sampling time is input into the decoupling module to obtain the decoupling output, and the system feedforward compensation is obtained by the double integral controller and the look-up table, and the sum of the two is input into the decoupling module to obtain the decoupling output, and the system speed-up instruction is jointly acted on the executing motor to adjust the running speed of plate roller until the end of the speed-up process.

Description

Technical Field

[0001] The present invention relates to the field of printing control technology, and in particular to a method and device for speed-up control of a color registration system based on double integration and feedforward. Background Art

[0002] During the printing process of an electronic axis gravure printing machine, complex color patterns are generally decomposed into multiple monochrome patterns and engraved on the printing plate roller for printing.

[0003] During printing, the printed material passes through each printing unit in a certain order. Each printing unit prints the corresponding monochrome pattern on the printed material, and finally forms a complex color pattern, which is called the color matching process.

[0004] During the steady-speed phase of color registration, each printing plate roller is driven by the same set of motors and operates at a constant speed, resulting in no significant tension fluctuations between color groups. During the accelerated phase of color registration, each printing plate roller is accelerated by the motors, while the guide rollers are accelerated by the tension between the printing materials on both sides. This means that there are significant tension fluctuations between the color groups. These tension fluctuations are related to acceleration and can have a serious impact on color registration accuracy, resulting in large color registration errors.

[0005] At the same time, the dynamic characteristics of the color registration system in the acceleration process will become more complex, and common control methods such as PD plus feedforward control and model predictive control can only achieve limited performance.

[0006] Given the importance of color registration accuracy to product quality, a control method for the speed-up process that can quickly and effectively reduce or eliminate color registration errors is particularly critical in industrial applications. Summary of the Invention

[0007] In view of the deficiency that the tension fluctuations generated in the existing electronic axis gravure printing system during the color registration speed-up process seriously affect the color registration accuracy, the present invention provides a color registration system speed-up control method and equipment based on double integration and feedforward, which effectively reduces the color registration error generated during the speed-up process.

[0008] The present invention is achieved through the following technical solutions:

[0009] A color registration system speed-up control method based on double integration and feedforward, comprising:

[0010] According to the steady-speed coupling mathematical model of the multi-color group of the color system, the coupling model is feedforward decoupled, and a decoupling module is designed to obtain the steady-speed decoupling model of the single-color group.

[0011] Design a speed-up open-loop experiment for the color system, collect the speed-up open-loop experimental data, and calculate the acceleration feedforward compensation of the single-color group based on the speed-up open-loop experimental data and the steady-speed decoupling model of the single-color group.

[0012] A double-integral controller is designed as a closed-loop controller based on the steady-speed decoupling model of the single-color group at different operating speeds. The designed double-integral controller can ensure the stability of the system during the speed increase from the starting speed to the target speed.

[0013] During the speed-up control process of the color registration system, the control output instruction quantity is calculated by the dual-integral controller according to the feedback quantity of the color registration error sensor at each sampling moment, and the system feedforward compensation quantity is obtained by looking up the table. The sum of the two is input into the decoupling module to obtain the decoupling output quantity, and it acts together with the system speed-up instruction on the execution motor to adjust the running speed of the plate roller until the speed-up process is completed.

[0014] Furthermore, the transfer function of the steady-speed decoupling model of the single-color group is:

[0015] ;

[0016] in, is the Laplace transform function of the color group color error signal, is the Laplace transform function of the motor position command signal, , V is the color group running speed, l is the unit material length, r is the printing plate roller radius, is the delay time, and L is the detection distance.

[0017] Furthermore, the speed-up open-loop experiment starts from the minimum operating speed and increases the speed until the maximum target operating speed is reached. The speed-up open-loop experiment data includes the color registration error, operating speed, and acceleration instruction of each color group at each sampling moment.

[0018] A storage medium stores a computer program, which implements the color registration system speed-up control method when executed by a processor.

[0019] A device includes a memory, a processor, and a color registration system speed-up control method stored in the memory and executable on the processor.

[0020] Compared with the prior art, the present invention has the following advantages and effects:

[0021] The color registration system speed-up control method based on double integration and feedforward of the present invention can effectively reduce the color registration error, improve the color registration accuracy, save costs and enhance economic benefits during the speed-up process of the color registration system.

[0022] The present invention is based on a color registration system speed-up control method with double integration and feedforward. On the basis of a steady-speed decoupling model, a double-integral controller is designed and used to suppress the disturbances generated during the speed-up process, thereby effectively reducing the color registration error generated during the system speed-up process and improving the color registration accuracy.

[0023] At the same time, the present invention calculates the feedforward compensation of system acceleration based on the speed-up open-loop experimental data, which is used for feedforward compensation during the speed-up process, thereby reducing the chromatic aberration error caused by acceleration changes during the speed-up process.

[0024] The control process of the present invention is simple and easy, and can be applied in the color registration process of an electronic axis gravure printing machine, thereby saving production costs and improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a workflow diagram of the present invention.

[0026] Figure 2 It is a curve chart of speed-up open-loop experimental data.

[0027] Figure 3 It is a structural diagram of the color registration control system of the present invention.

[0028] Figure 4 This is a graph showing the registration error for each color group when the speed increases from 30 m / min to 200 m / min. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0030] like Figure 1 As shown, the present invention discloses a color registration system speed-up control method based on double integration plus feedforward, which can be implemented by the following steps:

[0031] According to the steady-speed coupling mathematical model of the multi-color group of the color system, S1 performs feedforward decoupling on the coupling model, designs a decoupling module, and obtains the steady-speed decoupling model of the single-color group.

[0032] Furthermore, the model of the decoupling module is determined as:

[0033] ;

[0034] in, is the Laplace transform function of the control output signal of the i-th color group after decoupling, is the Laplace transform function of the control output signal of the jth color group after decoupling, is the Laplace transform function of the control output signal of the ith color group before decoupling, is a feed-forward compensation controller for eliminating the coupling effect of the jth color group on the ith color group, which is in the form of:

[0035] ;

[0036] wherein, is a decoupling controller parameter, V is the color group running speed, and l is the machine group length.

[0037] Further, the transfer function of the single-color group steady-speed decoupling model is in the form of:

[0038] ;

[0039] wherein, is the Laplace transform function of the color group color matching error signal, is the Laplace transform function of the executing motor position command signal, V is the color group running speed, l is the machine group length, and r is the printing plate roller radius, is the time delay time, and L is the detection distance.

[0040] S2 designs a color matching system speed-up open-loop experiment, collects speed-up open-loop experiment data, and calculates the single-color group acceleration feed-forward compensation amount according to the speed-up open-loop experiment data and the single-color group steady-speed decoupling model.

[0041] Further, the speed-up open-loop experiment starts from the minimum working running speed and speeds up until the maximum target running speed is reached.

[0042] Further, the speed-up open-loop experiment data include the color matching error, running speed, and acceleration command of each color group at each sampling time.

[0043] Further, the color matching error caused by the system speed-up command in the speed-up open-loop experiment can be considered as a disturbance signal applied to the input end of the steady-speed decoupling model, which has a corresponding relationship with the system acceleration command. Therefore, the calculation method of the acceleration feed-forward compensation amount is as follows:

[0044] First, the steady-speed decoupling model is subjected to z transformation to obtain the following z transformation model:

[0045] ;

[0046] wherein, is the sampling time, C is the plate roller circumference, and V is the running speed. n and m are model parameters, n is an integer, and m is a decimal less than 1, is the time delay time.

[0047] Secondly, the differential equations of the input and output signals obtained from the z-transform model are as follows:

[0048] ;

[0049] Where k is the sampling time, u(k) is the equivalent disturbance input signal to be calculated, and y(k) is the chromatic error data of the speed-up open-loop experiment. The calculated u(k) is matched with the acceleration command at the corresponding sampling time. If there are multiple input signals of different sizes corresponding to the same acceleration command, mean filtering should be performed. Thus, the corresponding acceleration feedforward compensation is obtained. .

[0050] S3 designs a double-integral controller as a closed-loop controller based on the steady-speed decoupling model of the single-color group at different operating speeds, and ensures the stability of the system during the speed-up process from the starting speed to the target speed.

[0051] The determination method of the dual-integral controller is as follows:

[0052] Considering that the object characteristics are time-varying during the speed increase process, it is expected that the designed controller will make the open-loop system With the frequency domain characteristics that meet the requirements, the parameters of the double-integral controller can be determined by the following formula:

[0053] ;

[0054] Furthermore, the transfer function of the desired open-loop system model is as follows:

[0055] ;

[0056] in, It is the parameter of the desired open-loop system, which determines the frequency domain Bode diagram of the open-loop system as well as system performance indicators such as phase and amplitude margin. is the object delay time.

[0057] Furthermore, the transfer function of the dual-integral controller is as follows:

[0058] ;

[0059] further, The value can be determined by frequency domain design method.

[0060] further, The value of is as follows:

[0061] According to the transfer function of the desired open-loop system, the system phase margin formula can be obtained:

[0062] ;

[0063] wherein, is the frequency, unit rad / s. For the system phase margin required by the process, the frequency corresponding to the phase margin is solved by gradient descent method, and then the value of is made to satisfy that at the frequency, the amplitude of the open-loop system is 1.

[0064] S4, in the speed-up control process of the color registration system, according to the feedback of the color registration error sensor at each sampling time, calculates the control output instruction quantity through the double integral controller and obtains the feedforward compensation quantity of the system through the look-up table, and the sum of the two is input to the decoupling module to obtain the decoupling output quantity, and the system speed-up instruction is jointly acted on the execution motor to adjust the running speed of the plate roller until the speed-up process is completed.

[0065] In this embodiment, the system device parameter values are as follows:

[0066] The plate roller circumference C=0.49m, the plate roller radius r=0.078m, the machine group length l=8.9m, the detection distance L=0.7m, the system running speed is increased from 30m / min to 200m / min, and the steady speed decoupling model of the single color group can be calculated and determined according to the parameters.

[0067] The speed-up open-loop experiment is designed, and the speed-up open-loop experiment data is collected as shown in Figure 2 , and the corresponding acceleration feedforward compensation quantity is calculated.

[0068] For the parameter values of the desired open-loop system, respectively 0.1 and 100.

[0069] The target phase margin of the desired open-loop system is 65°, and the value of is determined.

[0070] The closed-loop control is carried out in the speed-up process of the color registration system, and the control block diagram is as shown in Figure 3 .

[0071] Figure 4 The color registration error curve of each color group in the speed-up process of the color registration system from 30m / min to 200m / min.

[0072] In summary, the color registration system speed-up control method based on double integral plus feedforward has the advantages of simple implementation, fast response speed and effective reduction of color registration error.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A color registration system speed-up control method based on double integration plus feedforward, characterized in that The steps include: S1. Based on the steady-speed coupling mathematical model of the multi-color group of the color system, perform feedforward decoupling on the coupling model and design a decoupling module to obtain a steady-speed decoupling model for the single-color group; S2. Design an open-loop speed-up experiment for the color system, collect data from the open-loop speed-up experiment, and calculate the acceleration feedforward compensation for the single-color group based on the data and the steady-speed decoupling model of the single-color group. S3. Design a dual-integral controller as a closed-loop controller based on the steady-speed decoupling model of the single-color group at different operating speeds. Ensure that the designed dual-integral controller can ensure system stability during the acceleration process from the starting speed to the target speed. S4: During the speed increase control process of the color registration system, according to the feedback amount of the color registration error sensor at each sampling moment, the control output instruction amount is calculated by the dual integral controller and the feedforward compensation amount of the system is obtained by table lookup. The sum of the two is input into the decoupling module to obtain the decoupling output amount, which acts together with the system speed increase instruction on the execution motor to adjust the running speed of the plate roller until the speed increase process is completed; In step S1, the model of the decoupling module is determined as: in, U i (s) is the Laplace transform function of the control output signal of the i-th color group after decoupling, U j (s) is the Laplace transform function of the control output signal of the jth color group after decoupling, U io (s) is the Laplace transform function of the control output signal of the i-th color group before decoupling, G c,i-j (s) is a feedforward compensation controller used to eliminate the coupling effect of the j-th color group on the i-th color group, and its form is: in, is the decoupling controller parameter, V is the color group running speed, and l is the unit material length.

2. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S1, the transfer function of the steady-speed decoupling model of the single-color group is: Where E(s) is the Laplace transform function of the color group color error signal, θ(s) is the Laplace transform function of the execution motor position command signal, V is the color group running speed, l is the unit material length, r is the printing plate roller radius, is the delay time, and L is the detection distance.

3. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S2, the speed-up open-loop test starts from the minimum operating speed and increases the speed until the maximum target operating speed is reached.

4. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S2, the speed-up open-loop experimental data includes the color registration error, operating speed, and acceleration instruction of each color group at each sampling moment.

5. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S2, the chromatic aberration error caused by the system speed increase command P0 in the speed increase open-loop experiment can be considered to be caused by the application of a disturbance signal at the input end of the steady-speed decoupling model. The disturbance signal corresponds to the acceleration command of the system. Therefore, the acceleration feedforward compensation is calculated as follows: First, perform z-transform on the steady-speed decoupling model to obtain the following z-transform model: in, is the sampling time, C is the circumference of the plate roller, V is the running speed, n and m are model parameters, n is an integer, m is a decimal less than 1, and τ is the time delay. between; Secondly, the differential equations of the input and output signals obtained from the z-transform model are as follows: in, k is the sampling time, u(k) is the equivalent disturbance input signal to be calculated, y(k) is the color error data of the speed-up open-loop experiment, The calculated u(k) is matched with the acceleration instruction at the corresponding sampling moment. If there are acceleration instructions of the same magnitude corresponding to multiple input signals of different magnitudes, mean filtering should be performed.

6. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S3, the method for determining the dual-integral controller is as follows: Considering that the object characteristics are time-varying during the speed increase process, the controller is designed so that the open-loop system G I (s) has the required frequency domain characteristics, the parameters of the double-integral controller can be determined by the following formula:

7. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S3, the transfer function of the open-loop system model is as follows: in, K, w a 、w b It is the parameter of the desired open-loop system, which determines the frequency domain Bode diagram of the open-loop system and the system performance indicators such as phase and amplitude margin. τ is the object delay time.

8. The color registration system speed-up control method based on double integration and feedforward according to claim 1 is characterized in that: In step S3, the transfer function of the dual-integral controller is as follows: w a 、w b The value can be determined by frequency domain design method; The value of K is determined as follows: The system phase margin formula can be obtained based on the transfer function of the expected open-loop system: Where ω is the frequency in rad / s; For the system phase margin required by the process, the frequency corresponding to the phase margin is obtained by the gradient descent method, and then the value of K is made to satisfy the amplitude of the open-loop system of 1 at this frequency.

9. A device comprising a memory, a processor, and the color registration system speed-up control method based on double integration and feedforward according to any one of claims 1 to 8, which is stored in the memory and can be run on the processor.

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