Printing machine material belt transmission tension recognition method based on bending shear vibration

Abstract

The invention discloses a printing machine material belt transmission tension recognition method based on bending shear vibration. The method comprises the steps that a material belt contact surface bending shear vibration signal is collected; constructing a dynamic coupling model of the material belt contact transmission system; constructing a material belt bending shear vibration function and a material belt contact bending tracking function; the constructed material belt bending shear vibration function and the material belt contact bending tracking function are substituted into a material belt contact transmission system dynamic coupling model, and material belt transmission tension is identified; and evaluating the transmission tension of the identified material belt. By means of the method, material belt conveying tension fluctuation caused by bending, shearing and vibration of the material belt can be accurately recognized, the problems of material belt deformation, wrinkling, fuzzy printing and the like caused by too large tension fluctuation are solved, and the printing quality is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of tension identification, and in particular relates to a method for identifying transmission tension of a printing press material belt based on bending shear vibration. Background Art

[0002] Printing equipment is an important tool for the development of the printing industry. Its accuracy directly affects the effect of printed products in serving the society. However, the tension of the printing belt changes greatly during the printing process, which will cause printing belt wrinkles, blurred or ghosting printing defects. The detection, identification and regulation of the tension of the printing transmission belt has become a key indicator for evaluating the performance of printed products.

[0003] During the printing process, the printing tape moves through multiple tape simple supports, and the tape tension is gradually differentiated, causing the tape transmission tension to fluctuate, which reduces the stability of the tape transmission and directly affects the quality of the printed product. In the tape transmission project, the unwinding reel and the rewinding reel are continuous, and the tape tension cannot be directly measured. How to accurately identify the tape transmission tension has become an important method and key technology to improve the quality of printed products. Summary of the invention

[0004] The purpose of the present invention is to provide a method for identifying the transmission tension of a printing press material belt based on bending and shearing vibration, which can accurately identify the fluctuations in the transmission tension of the material belt caused by the bending and shearing vibration of the material belt, prevent problems such as deformation and wrinkling of the material belt and blurred printing caused by excessive tension fluctuations, and ensure printing quality.

[0005] The technical solution adopted by the present invention is a method for identifying transmission tension of a printing press material belt based on bending shear vibration, which specifically comprises the following steps: S1: Collect bending and shear vibration signals of the contact surface of the material strip; S2: Construct the dynamic coupling model of the material belt contact transmission system; S3: constructing the strip bending shear vibration function and the strip contact bending tracking function; S4: Bring the constructed material strip bending shear vibration function and material strip contact bending tracking function into the material strip contact transmission system dynamic coupling model to identify the material strip transmission tension; S5: Evaluate the identified web transport tension.

[0006] The present invention is also characterized in that: S1 is specifically: During the transmission of the printed material strip, a contact force is applied under the material strip, and the normal bending of the material strip under the contact force is measured; the object applying the contact force under the material strip is a spherical object with a radius of not less than 1 cm; the normal bending of the material strip is measured by laser dot array measurement, and the bending of the material strip under shear under the contact force is recorded; the contact force measurement and the corresponding laser dot array measurement of the normal bending of the material strip under the contact force are distributed in two groups along the width of the material strip, and the distance from the two free edges is not less than 5 cm.

[0007] The dynamic coupling model of the material belt contact transmission system constructed by S2 is expressed as: (1) In the formula, is the bending shear vibration function of the strip, , They are the first-order derivative and the second-order derivative of the bending shear vibration function of the strip respectively; is the strip bending stiffness, E is the elastic modulus of the strip, h is the strip thickness, L is the length of the strip; N The number of points measured by laser in the width direction of the strip; is the length direction coordinate of the material strip; is the coordinate in the width direction of the material strip; Strip surface pressure, t For time; b is the strip width; for Directional strip contact bending tracking function; for Directional strip contact bending tracking function; is the strip area mass density; v is the Poisson’s ratio of the strip material.

[0008] In S3, the bending and shear vibration function of the material strip is constructed. Under the linear elastic relationship, the surface pressure of the strip is expressed as: (2) In the formula, F is the strip contact force, is a discrete function; The bending shear vibration function of the material strip under the contact force is expressed as: (3) In the formula, M The number of points measured by laser in the length direction of the strip; m Number the laser measurement points in the length direction; N The number of points measured by laser in the width direction of the strip. nNumber the laser measurement points in the width direction; is the anti-resonance amplitude of the strip bending vibration; is the resonant amplitude of the strip bending vibration.

[0009] The strip contact bending tracking functions constructed in S3 are: (4) (5) In the formula, for Directional strip contact bending tracking function; for Directional strip contact bending tracking function.

[0010] S4 is specifically: Substituting formulas (3), (4), and (5) into the dynamic coupling model formula (1) of the material belt contact transmission system, we can obtain the material belt tension: T , tension fluctuation ratio σ Contact force F The relationship between them is used to construct the strip transmission tension identification model, which is expressed as follows: (6) Where: (7) , (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (twenty one) The belt tension is calculated by T and tension fluctuation coefficient σ .

[0011] S5 is as follows: S501: Constructing a tension identification progress evaluation model; S502: Calculating the error of transmission belt tension identification; S503: Compare the calculated error of transmission tape tension identification with the error threshold. If it is not less than the error threshold, adjust the number of laser dot arrays in the length and width directions, i.e., M and N, and re-identify and evaluate the tape transmission tension until the calculated error of transmission tape tension identification is less than the threshold.

[0012] S501 builds a tension recognition progress evaluation model, According to formula (6), the contact stiffness and strip tension are constructed T The relationship between and is used to establish the strip tension bending contact stiffness function, which is expressed as follows: (twenty two) In the formula, is the linear coefficient of bending stiffness related to the strip thickness, is the third coefficient of bending stiffness related to the strip thickness, h is the strip thickness; The local contact stiffness coefficient of the strip is: (twenty three) Construct the error function of the transmission belt tension identification, the expression is: (twenty four) In the formula, r is the total number of measured positions, is the displacement of the normal bending variable in the length direction of the strip, is the displacement of the normal bending variable in the width direction of the strip.

[0013] The beneficial effects of the present invention are: 1. The present invention aims at the material belt transmission system of the printing machine, establishes a dynamic coupling model of the light-touch material belt contact transmission system, and comprehensively characterizes the dynamic characteristics of the material belt coupling effect of the spherical contact effect; 2. The present invention constructs a bending shear vibration function of the material strip according to the vibration characteristics of the material strip bending amount, and comprehensively explains the mapping relationship between the bending shear vibration of the material strip and the bending deformation under light touch; 3. The present invention constructs a material strip contact bending tracking function to characterize the lateral and longitudinal bending deformation laws of the material strip under light touch; 4. The present invention constructs a belt transmission tension identification model based on the dynamic coupling model of the belt contact transmission system, and characterizes the nonlinear relationship between the bending shear vibration deformation and the belt transmission tension through matrix transmission, thus avoiding tension identification errors caused by ambiguous solutions of nonlinear mapping; 5. The present invention uses bending shear stiffness to characterize tension identification error, evaluates the accuracy of the tension identification model, and provides a theoretical standard for improving tension identification accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flowchart of a method for identifying transmission tension of a printing press material belt based on bending shear vibration of the present invention; Figure 2 It is a schematic diagram of the position of contact force measurement and laser dot matrix bending amount measurement under the corresponding contact force in the method for identifying the transmission tension of the printing press material belt based on bending shear vibration of the present invention; Figure 3 It is a flowchart of the tension recognition accuracy adjustment and evaluation process of the printing press material belt transmission tension recognition method based on bending shear vibration of the present invention. DETAILED DESCRIPTION

[0015] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] The present invention provides a method for identifying transmission tension of a printing press material belt based on bending and shearing vibration. Figure 1 As shown, the specific steps include: S1: Collect bending and shear vibration signals of the contact surface of the material strip.

[0017] During the transmission of the printed tape, a contact force is applied under the tape, and the normal bending amount of the tape under the contact force is measured. The object applying the contact force under the tape is a spherical object to avoid scratching or plastic deformation of the tape, and the radius is not less than 1cm. The normal bending amount of the tape is measured by laser dot matrix measurement, and the bending amount of the tape under shearing under the contact force is recorded. Contact force measurement and corresponding contact force for the normal bending amount of the tape measured by laser dot matrix, such as Figure 2 As shown, the contact ball is arranged below the material strip, a contact force monitoring device is arranged below the contact ball, a laser vibrometer is arranged above the material strip, two groups of test devices are distributed along the width direction of the material strip, and each group of test devices is not less than 5 cm away from the two free edges.

[0018] S2: Construct the dynamic coupling model of the material belt contact transmission system, which is expressed as: (1) In the formula, is the bending shear vibration function of the strip, , They are the first-order derivative and the second-order derivative of the bending shear vibration function of the strip respectively; is the strip bending stiffness, E is the elastic modulus of the strip, h is the strip thickness, L is the length of the strip; N The number of points measured by laser in the width direction of the strip; is the length direction coordinate of the material strip; is the coordinate in the width direction of the material strip; Strip surface pressure, t For time; b is the strip width; for Directional strip contact bending tracking function; for Directional strip contact bending tracking function; is the strip area mass density; v is the Poisson’s ratio of the strip material.

[0019] S3: Construct the strip bending shear vibration function and the strip contact bending tracking function.

[0020] Construct the strip bending shear vibration function, Under the linear elastic relationship, the surface pressure of the strip is expressed as: (2) In the formula, F is the strip contact force, is a discrete function; The bending shear vibration function of the material strip under the contact force is expressed as: (3) In the formula, M The number of points measured by laser in the length direction of the strip; m Number the laser measurement points in the length direction; N The number of points measured by laser in the width direction of the strip. n Number the laser measurement points in the width direction; is the anti-resonance amplitude of the strip bending vibration; is the resonant amplitude of the strip bending vibration.

[0021] The constructed strip contact bending tracking functions in the strip length direction and the strip width direction are: (4) (5) In the formula, for Directional strip contact bending tracking function; for Directional strip contact bending tracking function.

[0022] S4: The constructed material strip bending shear vibration function and material strip contact bending tracking function are introduced into the material strip contact transmission system dynamic coupling model to identify the material strip transmission tension.

[0023] Substituting formulas (3), (4), and (5) into the dynamic coupling model formula (1) of the material belt contact transmission system, we can obtain the material belt tension: T , tension fluctuation ratio σ Contact force F The relationship between them is used to construct the strip transmission tension identification model, which is expressed as follows: (6) Where: (7) , (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (twenty one) The belt tension is calculated by T and tension fluctuation coefficient σ .

[0024] S5: Evaluate the identified web transport tension.

[0025] The specific steps include: S501: Construct a tension identification progress evaluation model.

[0026] According to formula (6), the contact stiffness and strip tension are constructed TThe relationship between is used to establish the strip tension bending contact stiffness function, which is expressed as follows: (twenty two) In the formula, is the linear coefficient of bending stiffness related to the strip thickness, is the third coefficient of bending stiffness related to the strip thickness, h is the strip thickness; The local contact stiffness coefficient of the strip is: (twenty three) Construct the error function of the transmission belt tension identification, the expression is: (twenty four) In the formula, r is the total number of measured positions, is the displacement of the normal bending variable in the length direction of the strip, is the displacement of the normal bending variable in the width direction of the strip.

[0027] S502: Calculate the error of the transmission belt tension identification; solve the belt local contact stiffness coefficient by using the belt tension T obtained in step S4 and formula (22), and then solve the error of the transmission belt tension identification by combining formula (23).

[0028] S503: Compare the calculated error of the transmission material belt tension identification with the error threshold. If it is not less than the error threshold, adjust the number of laser dot arrays in the length and width directions, i.e., M and N, and re-identify and evaluate the material belt transmission tension until the calculated error of the transmission material belt tension identification is less than the threshold. The process is as follows: Figure 3 The threshold value is set according to the actual printing quality requirements.

[0029] The printing press material belt transmission tension identification method based on bending and shear vibration provided by the present invention transmits the material belt below through a contact ball, and measures the deformation of the upper surface of the material belt with a laser dot matrix to implement the detection of the bending and shear vibration of the material belt, and establishes a dynamic coupling model of the material belt transmission system under light touch contact, and comprehensively characterizes the dynamic characteristics of the material belt coupling effect under spherical contact; further, a material belt bending and shear vibration function is constructed, and the mapping relationship between the bending and shear vibration of the material belt and the bending deformation under light touch is comprehensively interpreted, and a material belt contact bending tracking function is established according to the evolution law of the bending deformation of the material belt, and the lateral and longitudinal bending deformation law of the material belt under light touch; at the same time, according to the dynamic coupling model of the material belt transmission system, a material belt transmission tension model is constructed, and the nonlinear relationship between the bending and shear vibration deformation and the material belt transmission tension is characterized by matrix transfer, thereby avoiding tension identification errors caused by ambiguous solutions of nonlinear mapping; in order to improve the accuracy of material belt transmission tension identification, the bending and shear stiffness is used to characterize the tension identification error, and the accuracy of the tension identification model is evaluated, providing a theoretical standard for improving the tension identification accuracy.

[0030] Example 1 This embodiment provides a method for identifying the transmission tension of a printing press material belt based on bending and shearing vibration. Figure 1 As shown, the specific steps include: S1: Collect bending and shear vibration signals of the contact surface of the material strip; S2: Construct the dynamic coupling model of the material belt contact transmission system; S3: constructing the strip bending shear vibration function and the strip contact bending tracking function; S4: Bring the constructed material belt bending shear vibration function and material belt contact bending tracking function into the material belt contact transmission system dynamic coupling model to identify the material belt transmission tension; S5: Evaluate the identified web transport tension.

[0031] Example 2 Based on Example 1, S1 is specifically: During the transmission of the printed material strip, a contact force is applied under the material strip, and the normal bending of the material strip under the contact force is measured; the object applying the contact force under the material strip is a spherical object with a radius of 2 cm; the normal bending of the material strip is measured by laser dot array measurement, and the bending of the material strip under shear under the contact force is recorded; the contact force measurement and the corresponding laser dot array measurement of the normal bending of the material strip under the contact force are distributed in two groups along the width of the material strip, 7 cm away from the two free edges.

[0032] Example 3 Based on Example 2, the material belt contact transmission system dynamic coupling model constructed by S2 is expressed as: (1) In the formula, is the bending shear vibration function of the strip, , They are the first-order derivative and the second-order derivative of the bending shear vibration function of the strip respectively; is the strip bending stiffness, E is the elastic modulus of the strip, h is the strip thickness, L is the length of the strip; N The number of points measured by laser in the width direction of the strip; is the length direction coordinate of the material strip; is the coordinate in the width direction of the material strip; Strip surface pressure, t For time; b is the strip width; for Directional strip contact bending tracking function; for Directional strip contact bending tracking function; is the strip area mass density; v is the Poisson’s ratio of the strip material.

[0033] Example 4 Based on Example 3, a strip bending shear vibration function is constructed in S3. Under the linear elastic relationship, the surface pressure of the strip is expressed as: (2) In the formula, F is the strip contact force, is a discrete function; The bending shear vibration function of the material strip under the contact force is expressed as: (3) In the formula, M The number of points measured by laser in the length direction of the strip; m Number the laser measurement points in the length direction; N The number of points measured by laser in the width direction of the strip. n Number the laser measurement points in the width direction; is the anti-resonance amplitude of the strip bending vibration; is the resonant amplitude of the strip bending vibration.

[0034] The strip contact bending tracking functions constructed in S3 are: (4) (5) In the formula, for Directional strip contact bending tracking function; for Directional strip contact bending tracking function.

[0035] Example 5 Based on Example 4, formulas (3), (4), and (5) are substituted into the dynamic coupling model formula (1) of the material belt contact transmission system to obtain the material belt tension: T , tension fluctuation ratio σ Contact force F The relationship between them is used to construct the strip transmission tension identification model, which is expressed as follows: (6) Where: (7) , (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (twenty one) The belt tension is calculated by T and tension fluctuation coefficient σ .

[0036] Example 6 On the basis of Example 5, S5 is specifically: S501: Constructing a tension identification progress evaluation model; S502: Calculating the error of transmission belt tension identification; S503: Compare the calculated error of transmission tape tension identification with the error threshold. If it is not less than the error threshold, adjust the number of laser dot arrays in the length and width directions, i.e., M and N, and re-identify and evaluate the tape transmission tension until the calculated error of transmission tape tension identification is less than the threshold.

[0037] S501 builds a tension recognition progress evaluation model, According to formula (6), the contact stiffness and strip tension are constructed T The relationship between and is used to establish the strip tension bending contact stiffness function, which is expressed as follows: (twenty two) In the formula, is the linear coefficient of bending stiffness related to the strip thickness, is the third coefficient of bending stiffness related to the strip thickness, h is the strip thickness; The local contact stiffness coefficient of the strip is: (twenty three) Construct the error function of the transmission belt tension identification, the expression is: (twenty four) In the formula, r is the total number of measured positions, is the displacement of the normal bending variable in the length direction of the strip, is the displacement of the normal bending variable in the width direction of the strip.

Claims

1. A method for identifying transmission tension of a printing press material belt based on bending and shear vibration, characterized in that: The specific steps include: S1: Collect bending and shear vibration signals of the contact surface of the material strip; S2: Construct the dynamic coupling model of the material belt contact transmission system; S3: constructing the strip bending shear vibration function and the strip contact bending tracking function; S4: Bring the constructed material belt bending shear vibration function and material belt contact bending tracking function into the material belt contact transmission system dynamic coupling model to identify the material belt transmission tension; S5: Evaluate the identified web transport tension.

2. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 1, characterized in that: S1 is specifically: During the transmission of the printed material strip, a contact force is applied under the material strip, and the normal bending of the material strip under the contact force is measured; the object applying the contact force under the material strip is a spherical object with a radius of not less than 1 cm; the normal bending of the material strip is measured by laser dot array measurement, and the bending of the material strip under shear under the contact force is recorded; the contact force measurement and the corresponding laser dot array measurement of the normal bending of the material strip under the contact force are distributed in two groups along the width of the material strip, and the distance from the two free edges is not less than 5 cm.

3. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 2, characterized in that: The dynamic coupling model of the material belt contact transmission system constructed by S2 is expressed as: （1） In the formula, is the bending shear vibration function of the strip, , They are the first-order derivative and the second-order derivative of the bending shear vibration function of the strip respectively; is the strip bending stiffness, E is the elastic modulus of the strip, h is the strip thickness, L is the length of the strip; N The number of points measured by laser in the width direction of the strip; is the length direction coordinate of the material strip; is the coordinate in the width direction of the material strip; Strip surface pressure, t For time; b is the strip width; for Directional strip contact bending tracking function; for Directional strip contact bending tracking function; is the strip area mass density; v is the Poisson’s ratio of the strip material.

4. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 3 is characterized in that: In S3, the material strip bending and shear vibration function is constructed. Under the linear elastic relationship, the surface pressure of the strip is expressed as: （2） In the formula, F is the strip contact force, is a discrete function; The bending shear vibration function of the material strip under the contact force is expressed as: （3） In the formula, M The number of points measured by laser in the length direction of the strip; m Number the laser measurement points in the length direction; N The number of points measured by laser in the width direction of the strip. n Number the laser measurement points in the width direction; is the anti-resonance amplitude of the strip bending vibration; is the resonant amplitude of the strip bending vibration.

5. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 4, characterized in that: The strip contact bending tracking functions constructed in S3 are: （4） （5） In the formula, for Directional strip contact bending tracking function; for Directional strip contact bending tracking function.

6. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 5, characterized in that: S4 is specifically: Substituting formulas (3), (4), and (5) into the dynamic coupling model formula (1) of the material belt contact transmission system, we can obtain the material belt tension: T , tension fluctuation ratio σ Contact force F The relationship between them is used to construct the strip transmission tension identification model, which is expressed as follows: （6） Where: （7） ， （8） （9） （10） （11） （12） （13） （14） （15） （16） （17） （18） （19） （20） （21） The belt tension is calculated by T and tension fluctuation coefficient σ .

7. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 6, characterized in that: S5 is as follows: S501: Constructing a tension identification progress evaluation model; S502: Calculating the error of transmission belt tension identification; S503: Compare the calculated error of transmission tape tension identification with the error threshold. If it is not less than the error threshold, adjust the number of laser dot arrays in the length and width directions, i.e., M and N, and re-identify and evaluate the tape transmission tension until the calculated error of transmission tape tension identification is less than the threshold.

8. The method for identifying transmission tension of a printing press material strip based on bending and shearing vibration according to claim 7, characterized in that: S501 builds a tension recognition progress evaluation model, According to formula (6), the contact stiffness and strip tension are constructed T The relationship between and is used to establish the strip tension bending contact stiffness function, which is expressed as follows: （22） In the formula, is the linear coefficient of bending stiffness related to the strip thickness, is the third coefficient of bending stiffness related to the strip thickness, h is the strip thickness; The local contact stiffness coefficient of the strip is: （23） Construct the error function of the transmission belt tension identification, the expression is: （24） In the formula, r is the total number of measured positions, is the displacement of the normal bending variable in the length direction of the strip, is the displacement of the normal bending variable in the width direction of the strip.

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