Speed raising control method for color register control system of electronic shaft intaglio printing press
By establishing a speed-up disturbance model in an electronic shaft gravure printer and designing feedforward, feedback and decoupling controllers, the problem of color-subtitled error control during speed-subtitled process is solved, high-precision color-subtitled control is achieved, and printing quality and economic benefits are improved.
Patent Information
- Application Number
- CN202510274243.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-10
- Publication Date
- 2025-07-08
AI Technical Summary
During the speed increase of the electronic shaft gravure printer, the color error is difficult to effectively control, resulting in a decrease in printing quality. Especially when external interference and system dynamic characteristics change, the traditional empirical PD feedback control method is difficult to meet the accuracy requirements.
Through the open-loop speed increase experiment, the speed increase disturbance model was established, and the feedforward, feedback and decoupling controllers were designed to offset the speed increase disturbance and adjust the roll speed respectively, so as to achieve separate control of each color group and suppress the color error.
During the speed increase process, the color error of the sleeve is effectively suppressed, the printing accuracy is maintained within ±0.15mm, the system stability and printing quality are improved, and the production cost is reduced.
Smart Images
Figure CN120269935A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of printing control, and more particularly, to a control method for a color registration control system during the speed-up process of an electronic shaft gravure press. Background Art
[0002] When performing color printing, the pattern to be printed is usually color-separated, and each color pattern is separated and then engraved on the printing plate cylinder of the electronic shaft gravure press respectively. During printing, when the printing material passes through each color group of the electronic shaft gravure press in sequence, the impression cylinder transfers each color pattern onto the printing material.
[0003] When the patterns of each color overlap in the color group order and at the designed fixed spacing, a vivid color pattern will be formed. However, when there are external interferences, the spacing between the corresponding printed patterns of each color group will deviate from the set value, and this difference is the so-called color registration error. At this time, the printed pattern will show a "ghosting" effect, and the printing quality will be severely degraded.
[0004] The accuracy of color registration is crucial for the printing precision. Therefore, it is essential to design a color registration controller to reduce and even eliminate the color registration error during the printing process. Compared with the color registration control at a steady speed, suppressing the color registration error during the speed-up process is often more difficult. This is because during the speed-up process, the dynamic characteristics of the system change with the running speed, and at the same time, due to the influence of the guide roller on the film tension between color groups, there is an additional color registration error disturbance related to acceleration.
[0005] In the application background where the required speed-up time is getting shorter and shorter, the traditional empirical PD feedback control method is difficult to keep the color registration error within the printing precision requirements during the entire speed-up process. Given the importance of color registration accuracy to product quality, a color registration control method that can quickly and effectively reduce or eliminate the color registration error during the speed-up process is particularly crucial in industrial applications. Summary of the Invention
[0006] The object of the present invention is to overcome the defects and deficiencies of the prior art, and provide a speed-up control method for a color registration control system of an electronic shaft gravure press, which can offset the color registration error caused by the speed-up disturbance, achieve individual control of each color group, and effectively suppress the color registration error during the speed-up process of the electronic shaft gravure press.
[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:
[0008] A speed-up control method for a color registration control system of an electronic shaft gravure press, comprising the following steps:
[0009] S1: Conduct an open-loop speed-up experiment on the electronic shaft gravure press, collect the register error data of each color unit during the speed-up process, and establish a speed-up disturbance model according to the register error data of each color unit and the mathematical model of register error and synchronous speed.
[0010] S2: Design a feed-forward controller of the register controller according to the speed-up disturbance model to cancel the register error caused by the speed-up disturbance.
[0011] S3: Design a feedback controller of the register controller according to the given amplitude margin and the mathematical model of register error and synchronous speed of a single color unit.
[0012] S4: Design a decoupling controller of the register controller according to the coupling model between color units to eliminate the influence of the output of the feed-forward controller and the output of the feedback controller of other color units on the register error of the current color unit.
[0013] S5: During the speed-up process, superimpose the output of the feed-forward controller, the output of the feedback controller, and the output of the decoupling controller onto the synchronous speed command and use them together as the speed command of the execution motor to adjust the running speed of the plate cylinder to ensure the register error accuracy.
[0014] Furthermore, the register error of a color unit is the difference between the distance between the color mark of the current color unit and the color mark of the first color unit and the set value.
[0015] The open-loop speed-up experiment is specifically as follows: Keep the linear speed of the plate cylinder of each color unit equal to the synchronous speed of the electronic shaft gravure press. The synchronous speed of the electronic shaft gravure press continuously accelerates from the starting speed to the target speed, and the adjustment amount of the linear speed of the plate cylinder of each color unit during the speed-up process is 0.
[0016] The synchronous speed is the linear speed of the plate cylinder of the first color unit, and it increases from the starting speed to the target speed according to the speed profile during speed-up.
[0017] Furthermore, the speed-up disturbance is a factor that causes the register error to change during the speed-up process and is related to the speed change amount. The speed-up disturbance model is the mathematical expression of the register error caused by the speed-up disturbance, expressed as:
[0018]
[0019] In the formula, e di (t) is the register error between the color mark of the i-th color unit and the color mark of the first color unit caused by the speed-up disturbance during the speed-up process; V * (t) is the synchronous speed; α i is the jerk coefficient; β i is the acceleration coefficient; jerk is the derivative of acceleration with respect to time.
[0020] The process of establishing the acceleration disturbance model is specifically as follows: Based on the mathematical model of the color registration error and the synchronous speed under open-loop acceleration, and based on the color registration error data of each color group obtained from the open-loop acceleration experiment, the coefficients α i and β i of the acceleration disturbance model are estimated.
[0021] Furthermore, during the open-loop acceleration process, the mathematical expression between the total color registration error of the color group and the color registration error caused by the acceleration disturbance is:
[0022]
[0023] Substituting the acceleration disturbance model into the above formula, the mathematical model of the color registration error and the synchronous speed under open-loop acceleration is obtained as:
[0024]
[0025] In the formula, e oi (t) is the color registration error between the color mark of the i-th color group and the color mark of the first color group during the open-loop acceleration process; e oi-1 (t) is the color registration error between the color mark of the (i - 1)-th color group and the color mark of the first color group during the open-loop acceleration process; l i is the length of the material film between the plate cylinder of the (i - 1)-th color group and the plate cylinder of the i-th color group.
[0026] Furthermore, based on the open-loop acceleration experiment data and the mathematical model of the color registration error and the synchronous speed under open-loop acceleration, the calculation formula for estimating α i and β i is:
[0027]
[0028] Y N = [Y(0) Y(1) … Y(N - 1)] T
[0029] X N = [X(0) T X(1) T … X(N - 1) T T
[0030] X N 、Y N are intermediate vectors constructed based on the open-loop acceleration experiment data, and the formula is:
[0031] Y N = [Y(0) Y(1) … Y(k) … Y(N - 1)] T
[0032] X N = [X(0) T X(1) T …X(k)…X(N - 1) T T
[0033] The calculation formula for the elements X(k) and Y(k) in the intermediate vector is:
[0034]
[0035] In the formula, k represents the k-th sampling; e oi (t k ) represents the open-loop speed-up color registration error of the i-th color group at the sampling time t k ; e oi-1 (t k ) represents the open-loop speed-up color registration error of the (i - 1)-th color group at the sampling time t k ; V * (t k ) represents the synchronous speed at the sampling time t k .
[0036] Furthermore, the calculation formula of the feed-forward controller is:
[0037]
[0038] In the formula, s represents the complex variable after the Laplace transform of the differential equation; A * is the derivative of the synchronous speed V * with respect to time, that is, the synchronous acceleration; is the speed feed-forward control amount output by the feed-forward controller of the i-th color group, which is superimposed on the speed command of the actuator motor as part of the total speed adjustment amount during the speed-up process.
[0039] Furthermore, the calculation formula of the feedback controller is:
[0040]
[0041] In the formula, e i is the total color registration error between the color mark of the i-th color group and the color mark of the first color group during the speed-up process; K Pi is the proportionality coefficient in the feedback controller of the i-th color group; K Di is the differential coefficient in the feedback controller of the i-th color group; during the speed-up process, K Pi and K Di parameters are automatically adjusted according to the given amplitude margin GM and the mathematical model of the color registration error and synchronous speed of a single color group; is the speed feedback control amount output by the feedback controller of the i-th color group, which is superimposed on the speed command of the actuator motor as part of the total speed adjustment amount during the speed-up process.
[0042] Furthermore, the unit of the amplitude margin GM is dB, and its mathematical meaning is:
[0043]
[0044] In the formula, P i represents the mathematical model of the overprint error and the synchronization speed of the i-th color group; G i (jω) is the frequency characteristic of the open-loop object after the feedback controller is added to the i-th color group; ω m is the frequency when the phase of the numerical frequency characteristic reaches -180°, that is, ∠G i (jω m ) = -180°;
[0045] The mathematical model of the overprint error and the synchronization speed of a single color group is:
[0046]
[0047] In the formula, τ is the internal time delay of the system; ΔV Pi is the change in the linear speed of the i-th plate cylinder relative to the synchronization speed; e pi is the overprint error between the color mark of the i-th color group and the color mark of the first color group caused by ΔV Pi ;
[0048] The mathematical model of the overprint error and the synchronization speed is used for the calculation of the K Pi and K Di parameters during the acceleration process. During the acceleration process, the calculation formulas for the K Pi and K Di parameters are:
[0049] K Pi = K adj V * , K D * = K adj l i
[0050] In the formula, K adj is the adjustment gain, and the calculation formula for the adjustment gain K adj is:
[0051]
[0052] Furthermore, the coupling model between color groups is:
[0053]
[0054] In the formula, e ciis the register error between the color mark of the i-th color group caused by the coupling effect and the color mark of the first color group; e i-1 is the total register error between the color mark of the (i - 1)-th color group and the color mark of the first color group during the acceleration process; ΔV Pi-1 is the change in the linear speed of the (i - 1)-th plate cylinder relative to the synchronous speed;
[0055] The output of the decoupling controller includes the decoupling amount for the feedforward controller of the previous color group and the decoupling amount for the feedback controller of the previous color group, and the calculation formula is:
[0056]
[0057] In the formula, is the decoupling amount for the feedforward controller of the previous color group, which cancels the output of the feedforward controller of the previous color group on the register error e of the current color group i effect; is the decoupling amount for the feedback controller of the previous color group, which cancels the output of the feedback controller of the previous color group on the register error e of the current color group i effect.
[0058] Furthermore, the actuator is a servo motor for driving the plate cylinder, the speed command is the desired linear speed of the plate cylinder driven by the actuator, and the calculation formula of the speed command is:
[0059] V Ri (t) = V R * (t) + Δv i (t)
[0060] In the formula, V Ri (t) is the speed command of the i-th color group at time t; V R * (t) is the synchronous speed command at time t; Δv i (t) is the speed adjustment amount output by the register controller, including the output of the feedforward controller, the output of the feedback controller, and the output of the decoupling controller, and the calculation formula is:
[0061]
[0062] Compared with the prior art, the speed-up control method of the register control system of the electronic shaft gravure printing machine of the present invention constructs a speed-up disturbance model based on the synchronous speed according to the speed-up open-loop experimental data, designs a feedforward controller through the speed-up disturbance model, and cancels the register disturbance related to the acceleration introduced by the guide roller during the speed-up process. At the same time, the proportional coefficient K Pi and the differential coefficient K DiA method for stabilizing parameters is provided, enabling automatic adjustment during the speed-up process according to the set amplitude margin and known system parameters.
[0063] The present invention avoids the blindness of empirical parameter tuning of traditional PD controllers, not only improving the stability of the system during the speed-up process but also maximizing the suppression effect of the system on the color registration error disturbance. The present invention also designs a decoupling controller to eliminate the effect of the coupling model between color groups and achieve independent control of each color group, unaffected by the adjustment amounts of other color groups. The control method of the present invention enables the color registration error to be within ±0.15 mm even under the working conditions of rapid speed-up of the electronic shaft gravure press, saving production costs and enhancing economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0064] Figure 1 It is a schematic flowchart of the speed-up control method for the color registration control system of the electronic shaft gravure press of the present invention.
[0065] Figure 2 It is a schematic structural diagram of the color registration control system of a single color group of the electronic shaft gravure press during the speed-up process in the embodiment.
[0066] Figure 3 It is the color registration error curve of each color group during the open-loop speed-up process of the electronic shaft gravure press in the embodiment.
[0067] Figure 4 It is a schematic diagram comparing the color registration error curve of the two-color group open-loop speed-up with the output of the speed-up disturbance model in the embodiment.
[0068] Figure 5 It is a schematic diagram comparing the color registration error curve of the three-color group open-loop speed-up with the output of the speed-up disturbance model in the embodiment.
[0069] Figure 6 It is a schematic diagram comparing the color registration error curve of the four-color group open-loop speed-up with the output of the speed-up disturbance model in the embodiment.
[0070] Figure 7 It is a schematic diagram comparing the color registration error curve of the five-color group open-loop speed-up with the output of the speed-up disturbance model in the embodiment.
[0071] Figure 8 It is a schematic diagram comparing the color registration error curve of the six-color group open-loop speed-up with the output of the speed-up disturbance model in the embodiment.
[0072] Figure 9 It is a schematic diagram comparing the color registration error curve of the seven-color group open-loop speed-up with the output of the speed-up disturbance model in the embodiment.
[0073] Figure 10 It is a schematic diagram of the color registration error curve under the action of the speed-up control method of the color registration control system of the electronic shaft gravure press in the embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0074] The speed-up control method of the color registration control system of the electronic shaft gravure press of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0075] Please refer to Figure 1 , the present invention discloses a speed-up control method for a color registration control system of an electronic shaft gravure press, including the following steps:
[0076] S1: Conduct an open-loop speed-up experiment on the electronic shaft gravure press, collect the color registration error data of each color group during the speed-up process, and establish a speed-up disturbance model according to the color registration error data of each color group and the mathematical model of color registration error and synchronous speed.
[0077] S2: According to the speed-up disturbance model, design a feed-forward controller for the color registration controller to offset the color registration error caused by the speed-up disturbance.
[0078] S3: According to the given amplitude margin and the mathematical model of color registration error and synchronous speed of a single color group, design a feedback controller for the color registration controller.
[0079] S4: According to the coupling model between color groups, design a decoupling controller for the color registration controller to eliminate the influence of the output of the feed-forward controller and the output of the feedback controller of other color groups on the color registration error of the current color group.
[0080] S5: During the speed-up process, superimpose the output of the feed-forward controller, the output of the feedback controller, and the output of the decoupling controller on the synchronous speed command and use it as the speed command of the execution motor together to adjust the running speed of the plate cylinder to ensure the accuracy of the color registration error.
[0081] The color registration error of a color group is the difference between the distance between the color mark of the current color group and the color mark of the first color group and the set value. The open-loop speed-up experiment is specifically: keep the linear speed of the plate cylinder of each color group equal to the synchronous speed of the electronic shaft gravure press, the synchronous speed of the electronic shaft gravure press continuously accelerates from the starting speed to the target speed, and the adjustment amount of the linear speed of the plate cylinder of each color group during the speed-up process is 0. The synchronous speed is the linear speed of the plate cylinder of the first color group, and it increases from the starting speed to the target speed according to the speed profile during speed-up.
[0082] Figure 2 It is a schematic structural diagram of the color registration control system of a single color group of the electronic shaft gravure press during the speed-up process. The color registration control system includes a color registration controller 201 for a single color group and a color group object 202. The color registration controller 201 includes a feed-forward controller 101, a feedback controller 102, and a decoupling controller 103. The color group object 202 includes an execution motor 104, a speed-up disturbance model 105, a mathematical model 106 of color registration error and synchronous speed, and a coupling model 107. Each color group of the electronic shaft gravure press has such a color registration control system.
[0083] In this embodiment, the execution motor 104 in the color group object 202 is regarded as the speed command V Ri to the linear speed V of the color group plate cylinder i The mathematical model between them is regarded as a direct link in engineering, and the transfer function is 1. The execution motor is a servo motor for driving the plate cylinder. The speed command is the desired linear speed of the color group plate cylinder driven by the execution motor.
[0084] The acceleration-up disturbance is a factor that causes the register error to change during the acceleration-up process and is related to the speed change amount. The acceleration-up disturbance model is the mathematical expression of the register error caused by the acceleration-up disturbance.
[0085] In this embodiment, the acceleration-up disturbance model 105 in the color group object 202 is expressed as:
[0086]
[0087] In the formula, e di (t) is the register error between the color mark of the i-th color group and the color mark of the first color group caused by the acceleration-up disturbance during the acceleration-up process; V * (t) is the synchronous speed. In this embodiment, V * (t) continuously accelerates from the starting speed of 30 m / min to the target speed of 200 m / min, and the acceleration-up time is 34 s; α i is the jerk coefficient; β i is the acceleration coefficient; the jerk is the derivative of the acceleration with respect to time.
[0088] The process of establishing the acceleration-up disturbance model is specifically as follows: According to the mathematical model of the register error and the synchronous speed under open-loop acceleration-up, based on the register error data of each color group obtained from the open-loop acceleration-up experiment, the coefficients α i and β i are estimated. α i and β i are unknowns and need to be estimated through the open-loop acceleration-up experiment, and the estimation results are used for the design of the feed-forward controller 101.
[0089] In this embodiment, the mathematical model 106 of the register error and the synchronous speed in the color group object 202 is:
[0090]
[0091] In the formula, τ is the internal time delay of the system. In this embodiment, τ is 1.2 s; ΔV Pi is the change amount of the linear speed of the i-th plate cylinder relative to the synchronous speed; e pi is the register error between the color mark of the i-th color group and the color mark of the first color group caused by ΔV Pi ; l iis the length of the material film between the (i - 1)-th color group plate cylinder and the i-th color group plate cylinder. In this embodiment, l i are all 7.4 m. The mathematical model of the color registration error and the synchronous speed will be used for calculating the proportional coefficient K Pi and the differential coefficient K Di parameters of the feedback controller 102 during the speed-up process.
[0092] In this embodiment, the coupling model 107 in the color group object 202 is as follows:
[0093]
[0094] where e ci is the color registration error between the color mark of the i-th color group and the color mark of the first color group caused by the coupling effect, and e i-1 is the total color registration error between the color mark of the (i - 1)-th color group and the color mark of the first color group during the speed-up process; ΔV Pi-1 is the change in the linear speed of the (i - 1)-th plate cylinder relative to the synchronous speed. The coupling model 107 will be used for the design of the decoupling controller 103.
[0095] In this embodiment, the calculation formula of the feed-forward controller 101 in the color registration controller 201 is:
[0096]
[0097] where A * is the derivative of the synchronous speed V * with respect to time, that is, the synchronous acceleration; is the speed feed-forward control quantity output by the feed-forward controller.
[0098] In this embodiment, the estimation of α i and β i is achieved through the following steps:
[0099] Keep the linear speed of each color group plate cylinder equal to the synchronous linear speed of the electronic shaft gravure press. The synchronous speed of the electronic shaft gravure press continuously increases from the starting speed of 30 m / min to the target speed of 200 m / min, and the speed-up time is 34 s. The adjustment amount of the linear speed of each color group plate cylinder during the speed-up process is 0. The saved open-loop speed-up experiment data are the color registration errors and the synchronous speed of each color group. The open-loop speed-up color registration errors of each color group are as Figure 3 shown, specifically including the color registration error curves of the 2-color group, 3-color group, 4-color group, 5-color group, 6-color group, and 7-color group.
[0100] According to the mathematical model of the color registration error and the synchronous speed under open-loop speed-up, calculate the parameters α i and β i . The mathematical model of the color registration error and the synchronous speed under open-loop speed-up is:
[0101]
[0102] In the formula, e oi (t) is the overprint error between the color mark of the i-th color group and the color mark of the first color group during the open-loop speed-up process.
[0103] For α i and β i The calculation formula for estimation is:
[0104]
[0105] Y N = [Y(0) Y(1) … Y(N - 1)] T
[0106] X N = [X(0) T X(1) T … X(N - 1) T T
[0107] X N 、Y N are intermediate vectors constructed based on the open-loop speed-up experiment data, and the formula is:
[0108] Y N = [Y(0) Y(1) … Y(k) … Y(N - 1)] T
[0109] X N = [X(0) T X(1) T … X(k) … X(N - 1) T T
[0110] The calculation formulas for the elements X(k) and Y(k) in the intermediate vector are:
[0111]
[0112] In the formula, k represents the k-th sampling; e oi (t k ) represents the open-loop speed-up overprint error of the i-th color group at the sampling time t k ; e oi-1 (t k ) represents the open-loop speed-up overprint error of the (i - 1)-th color group at the sampling time t k ; V * (t k ) represents the synchronous speed at the sampling time t k .
[0113] Bring the estimated results of α i and β i into the mathematical model of the color register error and the synchronous speed under open-loop speed increase, and compare the estimated open-loop speed increase color register error with the actually measured open-loop speed increase color register error curve, as shown in Figures 4 to 9 It shows that the method proposed by the present invention is relatively accurate in estimating α i and β i .
[0114] Among them, the schematic diagram of the comparison between the open-loop speed increase color register error curve of the two-color group and the output of the speed increase disturbance model is shown in Figure 4 . The schematic diagram of the comparison between the open-loop speed increase color register error curve of the three-color group and the output of the speed increase disturbance model is shown in Figure 5 . The schematic diagram of the comparison between the open-loop speed increase color register error curve of the four-color group and the output of the speed increase disturbance model is shown in Figure 6 . The schematic diagram of the comparison between the open-loop speed increase color register error curve of the five-color group and the output of the speed increase disturbance model is shown in Figure 7 . The schematic diagram of the comparison between the open-loop speed increase color register error curve of the six-color group and the output of the speed increase disturbance model is shown in Figure 8 . The schematic diagram of the comparison between the open-loop speed increase color register error curve of the seven-color group and the output of the speed increase disturbance model is shown in Figure 9 .
[0115] In this embodiment, the input of the feedback controller 102 in the color register controller 201 is the current color group color register error e i after inversion, and the output is the feedback control amount . The calculation formula is:
[0116]
[0117] In the formula, K Pi and K Di The parameter calculation formula is:
[0118] K Pi =K adj V * , K D * =K adj l i .
[0119] In the formula, K adj is the adjustment gain.
[0120] The calculation formula of the adjustment gain K adj is:
[0121]
[0122] In the formula, GM is the amplitude margin, which is set to 15 dB in this embodiment.
[0123] In this embodiment, the mathematical expression of the coupling model 107 in the color group object 202 is as follows:
[0124]
[0125] In the formula, e ci is the overprint error between the i-th color group color mark and the first color group color mark caused by the coupling effect; e i-1 is the total overprint error between the (i - 1)-th color group color mark and the first color group color mark during the speed-up process; ΔV Pi-1 is the change in the line speed of the (i - 1)-th plate cylinder relative to the synchronous speed.
[0126] In this embodiment, the input of the decoupling controller 103 in the color register controller 201 is the output of the feed-forward controller of the previous color group j ≤ i - 1 and the output of the feedback controller j ≤ i - 1, and the output is the decoupling amount for the feed-forward controller of the previous color group and the decoupling amount for the feedback controller of the previous color group The calculation formula is:
[0127]
[0128] In this embodiment, during the speed-up process of each color group motor, the speed command V Ri (t) input to the actuator motor is:
[0129] V Ri (t) = V R * (t) + Δv i (t)
[0130] In the formula, V Ri (t) is the speed command of the i-th color group at time t; V R * (t) is the synchronous speed command at time t; Δv i (t) is the speed adjustment amount output by the color register controller, including the output of the feed-forward controller, the output of the feedback controller, and the output of the decoupling controller. The calculation formula is:
[0131]
[0132] In this embodiment, during the process of the electronic shaft gravure press color register control system accelerating from the initial running speed of 30 m / min to the target running speed of 200 m / min within 34 s, the overprint error curve graphs of each color group under the action of the acceleration control method are as Figure 10As shown, during the entire acceleration process, the color registration error of each color group remains within ±0.15 mm. It shows that the acceleration control method of the color registration control system for the electronic shaft gravure press based on the present invention can effectively suppress the color registration error disturbance during the acceleration process and ensure the required printing accuracy even in the industrial scenario of rapid acceleration.
[0133] In summary, for the acceleration control method of the color registration control system for the electronic shaft gravure press of the present invention, based on the open-loop experimental data of acceleration, an acceleration disturbance model based on the synchronous speed is constructed, and a feed-forward controller is designed through the acceleration disturbance model to offset the color registration disturbance related to acceleration introduced by the guide roller during the acceleration process. At the same time, a method for stabilizing the proportional coefficient K Pi and the differential coefficient K Di parameters is proposed, so that it can be automatically adjusted during the acceleration process according to the set amplitude margin and known system parameters.
[0134] The present invention avoids the blindness of empirical parameter adjustment of the traditional PD controller, not only improves the stability of the system during the acceleration process, but also improves the suppression effect of the system on the color registration error disturbance as much as possible. The present invention also designs a decoupling controller to eliminate the effect of the coupling model between color groups and achieve independent control of each color group without being affected by the adjustment amounts of other color groups. The control method of the present invention enables the color registration error to be within ±0.15 mm even under the working condition of rapid acceleration of the electronic shaft gravure press, saving production costs and enhancing economic benefits.
[0135] The above description is a detailed description of the preferred feasible embodiment of the present invention, but the embodiment is not intended to limit the patent application scope of the present invention. Any equivalent changes or modifications made under the technical spirit disclosed by the present invention shall fall within the patent scope covered by the present invention.
Claims
1. A method for accelerating speed control of a color register control system of an electronic shaft gravure press, characterized in that, It includes the following steps: S1: Conduct an open-loop speed-up experiment on the electronic shaft gravure press, collect the color registration error data of each color group during the speed-up process, and establish a speed-up disturbance model according to the color registration error data of each color group and the mathematical model of color registration error and synchronous speed; S2: Design a feed-forward controller of the color registration controller according to the speed-up disturbance model to offset the color registration error caused by the speed-up disturbance; S3: Design a feedback controller of the color registration controller according to the given amplitude margin and the mathematical model of the color registration error and synchronous speed of a single color group; S4: Design a decoupling controller of the color registration controller according to the coupling model between color groups to eliminate the influence of the output of the feed-forward controller and the output of the feedback controller of other color groups on the color registration error of the current color group; S5: During the speed-up process, superimpose the output of the feed-forward controller, the output of the feedback controller, and the output of the decoupling controller on the synchronous speed command and use it as the speed command of the execution motor to adjust the running speed of the plate cylinder to ensure the color registration error accuracy.
2. The acceleration control method of the color registration control system for an electronic shaft gravure printing machine according to claim 1, characterized in that, The color registration error of a color group is the difference between the distance between the color mark of the current color group and the color mark of the first color group and the set value; The open-loop speed-up experiment is specifically as follows: Keep the linear speed of the plate cylinder of each color group equal to the synchronous speed of the electronic shaft gravure press, and the synchronous speed of the electronic shaft gravure press continuously accelerates from the starting speed to the target speed. During the speed-up process, the adjustment amount of the linear speed of the plate cylinder of each color group is 0; The synchronous speed is the linear speed of the plate cylinder of the first color group, and it increases from the starting speed to the target speed according to the speed profile during speed-up.
3. The speed increase control method of the color register control system of the electronic shaft gravure printing press according to claim 1, characterized in that, The speed-up disturbance is a factor that causes the color registration error to change during the speed-up process and is related to the speed change amount. The speed-up disturbance model is the mathematical expression of the color registration error caused by the speed-up disturbance, which is expressed as: where, e di (t) is the color registration error between the i-th color group color mark and the first color group color mark caused by the speed-up disturbance during the speed-up process; V * (t) is the synchronous speed; α i is the jerk coefficient; β i is the acceleration coefficient; the jerk is the derivative of the acceleration with respect to time; The process of establishing the acceleration disturbance model is specifically as follows: Based on the mathematical model of the color register error and the synchronous speed under open-loop acceleration, and using the color register error data of each color group obtained from the open-loop acceleration experiment, estimate the coefficients α i and β i of the acceleration disturbance model.
4. The method for accelerating control of the color registration control system of an electronic shaft gravure printing machine according to claim 3, wherein During the open-loop speed-up process, the mathematical expression between the total color registration error of a color group and the color registration error caused by the speed-up disturbance is: Substitute the speed-up disturbance model into the above formula to obtain the mathematical model of color registration error and synchronous speed under open-loop speed-up as: where e oi (t) is the overprint error between the color mark of the i-th color group and the color mark of the first color group during the open-loop speed-up process; e oi-1 (t) is the overprint error between the color mark of the (i - 1)-th color group and the color mark of the first color group during the open-loop speed-up process; l i is the length of the material film between the plate cylinder of the (i - 1)-th color group and the plate cylinder of the i-th color group.
5. The speed-up control method for the color registration control system of the electronic shaft gravure press according to claim 4, characterized in that, Based on the open-loop speed-up experiment data and the mathematical model of the overprint error and the synchronous speed under open-loop speed-up, the calculation formula for estimating α i and β i is as follows: Y N = [Y(0) Y(1) … Y(N - 1)] T X N = [X(0) T X(1) T …X(N - 1) T T X N 、Y N are intermediate vectors constructed based on the open-loop speed-up experiment data, and the formula is: Y N = [Y(0) Y(1) … Y(k) … Y(N-1)] T X N = [X(0) T X(1) T …X(k)…X(N-1) T T The calculation formulas for the elements X(k) and Y(k) in the intermediate vector are: In the formula, k represents the kth sampling; e oi (t k ) represents the open-loop speed-up color registration error of the i-th color group at the sampling time t; e k at time t oi-1 (t k ) represents the open-loop speed-up color registration error of the (i - 1)-th color group at the sampling time t; V k at time t * (t k ) represents the synchronous speed at the sampling time t k at time t 6. The speed increase control method of the color registration control system of the electronic shaft gravure printing machine according to claim 5, characterized in that The calculation formula of the feed-forward controller is: where s represents the complex variable after the Laplace transform of the differential equation; A * is the derivative of the synchronous speed V * with respect to time, i.e., the synchronous acceleration; is the speed feedforward control quantity output by the feedforward controller of the i-th color group, which is superimposed on the speed command of the actuator motor as part of the total speed adjustment during the speed-up process.
7. The speed-up control method for the color registration control system of an electronic shaft gravure press according to claim 6, characterized in that, The calculation formula of the feedback controller is: Where, e i is the total color registration error between the color mark of the i-th color group and the color mark of the first color group during the acceleration process; K Pi is the proportional coefficient in the feedback controller of the i-th color group; K Di is the differential coefficient in the feedback controller of the i-th color group; during the acceleration process, K Pi and K Di parameters are automatically adjusted according to the given amplitude margin GM and the mathematical model of the color registration error and synchronous speed of a single color group; is the speed feedback control amount output by the feedback controller of the i-th color group, and is superimposed on the speed command of the actuator motor as part of the total speed adjustment amount during the acceleration process.
8. The speed-up control method of the color registration control system of the electronic shaft gravure printing machine according to claim 7, characterized in that, The unit of the amplitude margin GM is dB, and its mathematical meaning is: Where P i represents the mathematical model of the overprint error and the synchronization speed of the i-th color group; G i (jω) is the frequency characteristic of the open-loop object after the feedback controller is added to the i-th color group; ω m is the frequency when the phase of the numerical frequency characteristic reaches -180°, that is, ∠G i (jω m ) = -180°; The mathematical model of the color registration error and synchronous speed of a single color group is: where τ is the internal time delay of the system; ΔV Pi is the change in the linear velocity of the i-th plate cylinder relative to the synchronous velocity; e pi is the register error between the color marks of the i-th color unit and the color marks of the first color unit caused by ΔV Pi ; The mathematical model of color registration error and synchronization speed is used for the calculation of K Pi and K Di parameters during the acceleration process. During the acceleration process, the calculation formulas for K Pi and K Di parameters are as follows: K Pi = K adj V * , K D * = K adj l i Where K adj is the adjustment gain; Adjust the gain K adj The calculation formula is as follows:
9. The speed-up control method of the color registration control system of the electronic shaft gravure press according to claim 8, characterized in that, The coupling model between color groups is: where, e ci is the overprint error between the color mark of the i-th color group caused by the coupling effect and the color mark of the first color group; e i-1 is the total overprint error between the color mark of the (i - 1)-th color group and the color mark of the first color group during the acceleration process; ΔV Pi-1 is the change in the linear velocity of the (i - 1)-th plate cylinder relative to the synchronous velocity; The output of the decoupling controller includes the decoupling amount for the feed-forward controller of the previous color group and the decoupling amount for the feedback controller of the previous color group, and the calculation formula is: In the formula, is the decoupling amount of the feedforward controller of the previous color group, which cancels the output of the feedforward controller of the previous color group on the overprint error e i of the current color group; is the decoupling amount of the feedback controller of the previous color group, which cancels the output of the feedback controller of the previous color group on the overprint error e i of the current color group.
10. The speed-up control method of the color registration control system of the electronic shaft gravure printing machine according to claim 9, characterized in that, The execution motor is the servo motor that drives the plate cylinder, the speed command is the desired linear speed of the plate cylinder driven by the execution motor, and the calculation formula of the speed command is: V Ri v(t) = V R * v(t)+Δv i v(t) where, V Ri (t) is the speed command of the i-th color group at time t; V R * (t) is the synchronous speed command at time t; Δv i (t) is the speed adjustment amount output by the color register controller, including the output of the feedforward controller, the output of the feedback controller, and the output of the decoupling controller. The calculation formula is: