Rotating speed tracking control method, system and equipment for six-roller reversible cold rolling mill and storage medium

Abstract

The invention relates to the field of distributed control, in particular to a rotating speed tracking control method, system and equipment for a six-roller reversible cold rolling mill and a storage medium. Comprising the following steps: determining kinetic models of a leader and a follower, determining a rotating speed tracking error system of a roller, designing a controller and a parameter updating law by applying a self-adaptive iterative learning control theory on this basis, and estimating unknown parameters by utilizing the parameter updating law. According to the method, all the rollers of the six-roller reversible cold rolling mill are regarded as intelligent agents, the self-adaptive iterative learning distributed control theory is applied, distributed cooperative rotating speed tracking control over the rollers is achieved, the rotating speed of the rollers can be adjusted in real time through the control mode, coordination and synchronism among all the rollers in the rolling process are ensured, and the rolling quality is improved. And therefore, the rolling precision of steel is remarkably improved, and the production requirement of higher standards is met.

Description

Technical Field

[0001] The invention relates to the field of distributed control, and in particular to a speed tracking control method, system, equipment and storage medium for a six-roller reversible cold rolling mill. Background Art

[0002] Modern steel rolling technology has always played an important role in the development of my country's industry. It is widely used in aerospace, building decoration, rail transportation, automobile manufacturing, household appliances, electronic information and other industries. In the field of high-end metal sheet processing, six-roller reversible cold rolling mills are the most widely used, including two working rolls, two intermediate rolls and two support rolls. During the rolling process, the speeds of the working rolls, intermediate rolls and support rolls need to be accurately matched. If the speeds of each roll are not coordinated, the rolled piece will slide relative to the rolls, which will not only affect the rolling efficiency, but also cause scratches and wear on the surface of the rolled piece due to uneven friction, affecting the surface quality of the product. The speed of each roll is controlled by its own motor; and the current domestic speed control is often limited to manual adjustment and traditional control methods, which affects the operation of the equipment and product quality. In recent years, with the rapid development of the economy, the demand for precision and high-quality steel in various industries in my country has continued to increase, and the old control methods cannot meet the new needs. Therefore, in order to improve the quality of steel rolled by the rolling mill and reduce the rolling cost, it is necessary to study the coordinated speed control of each roll.

[0003] An agent is an entity with autonomy, interactivity and responsiveness, which can perceive the environment, make decisions and perform actions. In a multi-agent system, multiple agents achieve common goals through collaboration and competition. The moving beam and the extrusion cylinder are regarded as agents, and the control strategy is designed to make the agents collaborate with each other to achieve accurate, efficient and stable control of the extrusion process of the extruder.

[0004] Iterative learning control is an intelligent control method. Its core idea is to repeatedly perform the same task and use the information from the previous or previous executions to correct the control inputs in the current and subsequent executions, so as to achieve complete tracking of the desired trajectory or target or gradual improvement of control performance. The control law designed using iterative learning control can effectively improve the accuracy of production products and reduce rolling costs. Summary of the invention

[0005] In response to the problems mentioned in the prior art, the present invention proposes a speed tracking control method, system, equipment and storage medium for a six-roller reversible cold rolling mill, which utilizes intelligent control technology to collaboratively control the relative speeds of each roller, so that the speed control accuracy is higher and the operation of the six rollers is smoother, thereby making the production process control more accurate, more stable, more efficient and less costly.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: The invention discloses a speed tracking control method for a six-roller reversible cold rolling mill, comprising the following steps: Based on the structure of six-roller reversible cold rolling mill, the roll dynamics model is constructed; The communication topology of the roller dynamics model is constructed based on graph theory knowledge, and the speed tracking error is determined according to the communication topology; According to the speed tracking error, a multi-roller distributed speed tracking control strategy is designed.

[0007] As a further improvement of the present invention, the roll dynamics model includes a follower dynamics model and a leader dynamics model, wherein the follower dynamics model represents the intermediate roll and the support roll, and the leader dynamics model represents the working roll; The follower dynamics model is:

[0008] Where: yes Agent The state variables of the iterations are ;; It is Agent The control input for the iteration; is the nonlinear perturbation parameter; yes The known local Lipschitz nonlinear function caused by nonlinear factors such as friction, material nonuniformity of rolled product, motor characteristics, etc. is the duration of the rolling process; The leader dynamics model is:

[0009] Where: is the working roll speed; The speed curve of the working roll when rolling steel, satisfying ,in Is a positive constant.

[0010] As a further improvement of the present invention, the communication topology of the roller dynamics model constructed based on graph theory knowledge includes: Constructing a weighted adjacency matrix , where if the node With Node If there is a communication connection, ,otherwise ; Constructing a diagonal matrix , among which The roller is a follower and can directly receive the leader's information, then ,otherwise ; Compute the Laplacian matrix ,in ; Superimpose the Laplacian matrix with the diagonal matrix to construct a symmetric matrix .

[0011] As a further improvement of the present invention, the tracking error system determined according to the communication topology includes: According to the symmetric matrix, the consistency error and general error based on the roller dynamics model are established. The consistency error expression is as follows:

[0012] The general error expression is as follows:

[0013] In each iterative control, the initial value of the current general error is set to the final value of the previous iteration, that is, , and the error equation is as follows:

[0014] Dynamic consistency control of the roll speed is achieved through the error equation.

[0015] As a further improvement of the present invention, according to the speed tracking error, a multi-roller distributed speed tracking control strategy is designed, including: Design control input for:

[0016] Where: is an adjustable design parameter; and is the parameter update rate; is the time-varying adjustment gain and satisfies ;and , ; Design parameter update law through composite energy function:

[0017]

[0018] Where: , is an adjustable design parameter.

[0019] As a further improvement of the present invention, after obtaining the multi-roller distributed speed tracking control strategy, the multi-roller distributed speed tracking control strategy is verified.

[0020] As a further improvement of the present invention, when the control input and parameter update rate iteration times are guaranteed to be infinite, the follower agent completely tracks the leader's expected speed trajectory in the sense of the two norm, that is, satisfies .

[0021] A six-roller reversible cold rolling mill speed tracking control system, comprising: A building module for building a roll dynamics model based on the structure of a six-roll reversing cold rolling mill; A determination module is used to construct a communication topology of a roller dynamics model based on graph theory knowledge, and to determine a speed tracking error according to the communication topology; Design module, according to the speed tracking error, design a multi-roller distributed speed tracking control strategy.

[0022] A six-roller reversible cold rolling mill speed tracking control device comprises a processor and a memory, wherein the processor implements the above-mentioned six-roller reversible cold rolling mill speed tracking control method when executing a computer program stored in the memory.

[0023] A computer-readable storage medium is used to store a computer program, wherein when the computer program is executed by a processor, the speed tracking control method of a six-roller reversible cold rolling mill as described above is implemented.

[0024] Compared with the prior art, the present invention has achieved the following technical effects: The present invention regards each roll of the six-roll reversible cold rolling mill as an intelligent entity, and applies adaptive iterative learning distributed control theory to realize distributed collaborative speed tracking control of the rolls. This control method can adjust the speed of the rolls in real time to ensure the coordination and synchronization between the rolls during the rolling process, thereby significantly improving the rolling accuracy of steel and meeting higher standards of production requirements.

[0025] Compared with traditional control methods, the present invention has the self-regulating ability. Through the autonomous learning and iterative optimization of the intelligent body, the system can roll steel with higher precision requirements under the influence of nonlinear factors, ensure the stability and controllability of the rolling process, and improve production efficiency and product quality.

[0026] The distributed control system of the present invention is scalable. As the production scale changes, the number of intelligent agents can be increased or decreased to adapt to different production needs. This flexibility enables the present invention to be widely used in cold rolling mill production lines of various sizes to meet different production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of six rollers in the six-roller reversible cold rolling mill of the present invention; Figure 2 The communication relationship between the rollers provided for verification of the embodiment of the present invention; Figure 3 Schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0029] It should be noted that the mechanical structure of the embodiment of the present invention is a six-roll reversible cold rolling mill, and the main research components include the two outermost support rolls, the two middle intermediate rolls and the innermost two working rolls that are directly in contact with the workpiece. With the development of modern industry, the demand for control accuracy and stability of rolling mills is constantly increasing. During the rolling process, the two working rolls are in direct contact with the workpiece and cause plastic deformation of the workpiece. The working rolls rotate and use friction to pull the workpiece into the roll gap, and under the action of pressure, the thickness of the workpiece is reduced and the length is increased, thereby realizing the basic function of cold rolling; the intermediate rolls are mainly used to adjust the plate shape of the workpiece. By moving the intermediate rolls axially, the force distribution of the working rolls can be changed, thereby effectively controlling the flatness of the workpiece; the main function of the support rolls is to provide strong support for the entire rolling process to withstand the huge rolling force. The working states of the six rolls are interrelated and affect the rolling effect of the steel.

[0030] Due to the limitations of manual adjustment and traditional control methods for roller speed control, one or more of the following nonlinear problems may be encountered in the speed control of six rollers: The friction between the roller and the workpiece is an important factor affecting the roller speed. The friction coefficient is not a fixed value. It changes with the rolling speed, rolling pressure, lubrication conditions, and the surface conditions of the workpiece and roller. This nonlinear change in the friction coefficient will cause changes in the rolling force and friction force, which in turn affects the speed of the roller; the nonlinear effect of the unevenness of the material of the workpiece. The rolled workpiece may have uneven material, such as uneven hardness distribution. When the hardness of the workpiece is different, the bite conditions of the roller on the workpiece and the rolling force distribution will change, and this rolling force change caused by the difference in material hardness is nonlinear, because the hardness change and the rolling force are not a simple linear relationship, which makes the roller speed control more complicated; nonlinear factors related to motor characteristics. When the motor current increases to a certain extent, the motor core will experience magnetic saturation. This will cause the inductance parameters of the motor to change, which will in turn affect the torque output and speed response of the motor. During long-term operation of the motor, the winding temperature will rise. The change in temperature will increase the resistance of the motor winding, thus affecting the performance of the motor and further affecting the speed of the roller. The present invention only provides theoretical guidance and temporarily considers the speed control of each roller.

[0031] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments: like Figure 1 As shown, the six-roller reversible cold rolling mill targeted by the present invention can be divided into two multi-agent systems. A working roll, an intermediate roll and a support roll are used as a multi-agent system. The present invention only designs a controller for one of the multi-agent systems, and the controller for the other multi-agent system can be designed in the same way. The control goal of the present invention is to design a distributed speed tracking controller for each roll to achieve: ,

[0032] The intermediate roll and the support roll can move precisely under the action of the controller to achieve high-precision position and speed control, and maintain the desired relative speed with the working roll; is the number of iterations, is the speed of the working roll, i.e. the expected speed, Indicates the speed status information of the follower. Represents the expected relative rotation speed between the follower and the leader.

[0033] Step 1: Consider each roller as an intelligent agent. The speed control of the multi-roller wheel can be regarded as a speed tracking control problem of multiple intelligent agents. Through the dynamics study of the rollers, the follower dynamics model is established, which represents the intermediate roller and the support roller, as shown below:

[0034] Where: yes Agent The state variables of the iterations are ; It is Agent The control input for the iteration; is the nonlinear perturbation parameter; yes The known local Lipschitz nonlinear function caused by nonlinear factors such as friction, material nonuniformity of rolled product, motor characteristics, etc. is the duration of the rolling process; The leader dynamics model represents the working roll as follows:

[0035] Where: is the working roll speed; The speed curve of the working roll when rolling steel, satisfying ,in Is a positive constant.

[0036] Step 2: The present invention considers the speed control of each roller in the case of a directed graph, such as Figure 2 shown.

[0037] The node relationship in a directed graph is represented by a weighted adjacency matrix. Construct a weighted adjacency matrix , where if the node With Node If there is a communication connection, ,otherwise .

[0038] Constructing a diagonal matrix , used to represent the communication topology relationship between followers and leaders. The roller is a follower and can directly receive the leader's information, then ,otherwise .

[0039] Compute the Laplacian matrix ,in ; Superimpose the Laplacian matrix with the diagonal matrix to construct a symmetric matrix , thus building a bridge between the consistency error and general error of the intelligent agent system.

[0040] The consistency error is defined based on the roller dynamics model as:

[0041] The general error is defined based on the roller dynamics model as:

[0042] In each iterative control, the initial value of the current general error is set to the final value of the previous iteration, that is, , and the error equation is as follows:

[0043] Where: .

[0044] The control goal of the present invention is to design appropriate control input and parameter update law so that the follower agent can completely track the leader agent in the sense of the two norm, that is:

[0045] Since the communication between the rollers is smooth, that is, the directed graphs between them are connected, we have:

[0046] in, Represents a symmetric matrix The minimum eigenvalue of , which ensures that:

[0047] At this point, the convergence of proving consistency error is converted to proving the convergence of general error.

[0048] Step 3: According to the speed tracking error and selecting the appropriate composite energy function, design the multi-roller distributed speed tracking control strategy.

[0049] First, the derivative of the speed tracking error is calculated as follows:

[0050] The composite energy function is selected as follows:

[0051] Where: , , , , , and is an adjustable positive constant.

[0052] Taking its derivative we get:

[0053] because , then:

[0054] In the formula, ,in, , for a given sequence ,have . , here .make , then:

[0055] Design control input for:

[0056] Where: is an adjustable design parameter.

[0057] Then we have:

[0058] Design parameter update law:

[0059]

[0060] Then we have:

[0061] Among them, the parameter update rate satisfies .

[0062] Step 4: Control input for the multi-agent system proposed in the present invention , parameter update law and It is ensured that when the number of iterations tends to infinity, the follower can completely track the expected speed trajectory of the leader in the sense of the two norm, that is, the speed coordinated control of multiple rolls in the six-roll reversible cold rolling mill is completed ( ).

[0063] This section is a detailed proof of the conclusion. The specific process is as follows: Proof: Order

[0064] in, .

[0065] Depend on , we can get:

[0066] make , then:

[0067] because , then:

[0068] Therefore, we can get is bounded. And because , then:

[0069] Therefore, we can get , and then get .

[0070] Based on the same inventive concept, an embodiment of the present invention also provides a six-roller reversible cold rolling mill speed tracking and control system. Since the principle of solving the problem by the six-roller reversible cold rolling mill speed tracking and control system is similar to the aforementioned six-roller reversible cold rolling mill speed tracking and control method, the implementation of the six-roller reversible cold rolling mill speed tracking and control system can refer to the implementation of the six-roller reversible cold rolling mill speed tracking and control method, and the repeated parts will not be repeated.

[0071] In specific implementation, the six-roller reversible cold rolling mill speed tracking and control system provided by the embodiment of the present invention specifically includes: A building module for building a roll dynamics model based on the structure of a six-roll reversing cold rolling mill; A determination module is used to construct a communication topology of a roller dynamics model based on graph theory knowledge, and to determine a speed tracking error according to the communication topology; Design module, according to the speed tracking error, design a multi-roller distributed speed tracking control strategy.

[0072] Correspondingly, an embodiment of the present invention also provides a six-roll reversible cold rolling mill speed tracking control device, comprising a processor and a memory, wherein the processor implements the six-roll reversible cold rolling mill speed tracking control method provided in the embodiment of the present invention when executing the computer program stored in the memory.

[0073] For more specific processes of the above method, please refer to the corresponding contents disclosed in the aforementioned embodiments, which will not be repeated here.

[0074] Correspondingly, an embodiment of the present invention further provides a computer-readable storage medium for storing a computer program, wherein when the computer program is executed by a processor, the above-mentioned six-roller reversible cold rolling mill speed tracking control method provided in the embodiment of the present invention is implemented.

[0075] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the systems, devices, and storage media disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0076] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0077] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0078] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0079] The above is a detailed introduction to the speed tracking control method, system, equipment and storage medium for the six-roll reversible cold rolling mill provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A six-roller reversible cold rolling mill speed tracking control method, characterized in that: The following steps are involved: Based on the structure of six-roller reversible cold rolling mill, the roll dynamics model is constructed; The communication topology of the roller dynamics model is constructed based on graph theory knowledge, and the speed tracking error is determined according to the communication topology; According to the speed tracking error, a multi-roller distributed speed tracking control strategy is designed.

2. According to claim 1, a six-roller reversible cold rolling mill speed tracking control method is characterized in that: The roll dynamics model includes a follower dynamics model and a leader dynamics model, wherein the follower dynamics model represents the intermediate roll and the support roll, and the leader dynamics model represents the working roll; The follower dynamics model is: Where: yes Agent The state variables of the iterations are ; It is Agent The control input for the iteration; is the nonlinear perturbation parameter; yes The known local Lipschitz nonlinear function caused by nonlinear factors such as friction, material nonuniformity of rolled product, motor characteristics, etc. is the duration of the rolling process; The leader dynamics model is: Where: is the working roll speed; The speed curve of the working roll when rolling steel, satisfying ,in Is a positive constant.

3. According to claim 1, a six-roller reversible cold rolling mill speed tracking control method is characterized in that: The communication topology of the roller dynamics model based on graph theory knowledge includes: Constructing a weighted adjacency matrix , where if the node With Node If there is a communication connection, ,otherwise ; Constructing a diagonal matrix , among which The roller is a follower and can directly receive the leader's information, then ,otherwise ; Compute the Laplacian matrix ,in ; Superimpose the Laplacian matrix with the diagonal matrix to construct a symmetric matrix .

4. The speed tracking control method of a six-roller reversible cold rolling mill according to claim 1, characterized in that: Determining the speed tracking error based on the communication topology includes: According to the symmetric matrix, the consistency error and general error based on the roller dynamics model are established. The consistency error expression is as follows: Where: Indicates The expected relative speed between the followers and the leader; The general error expression is as follows: In each iterative control, the initial value of the current general error is set to the final value of the previous iteration, that is, , and the error equation is as follows: Where: ; Dynamic consistency control of the roll speed is achieved through the error equation.

5. The speed tracking control method of a six-roller reversible cold rolling mill according to claim 1, characterized in that: According to the speed tracking error, the multi-roller distributed speed tracking control strategy is designed including: Design control input for: Where: is an adjustable design parameter; and is the parameter update rate; is the time-varying adjustment gain and satisfies ;and , ; Design parameter update law through composite energy function: Where: , is an adjustable design parameter.

6. The speed tracking control method of a six-roller reversible cold rolling mill according to claim 1, characterized in that: After obtaining the multi-roller distributed speed tracking control strategy, the multi-roller distributed speed tracking control strategy is verified.

7. A six-roller reversible cold rolling mill speed tracking control method according to claim 6, characterized in that: When the number of iterations of the control input and parameter update rate is guaranteed to be infinite, the follower agent completely tracks the leader's expected speed trajectory in the sense of the two norm, that is, it satisfies .

8. A six-roller reversible cold rolling mill speed tracking control system, characterized in that: include: A building module for building a roll dynamics model based on the structure of a six-roll reversing cold rolling mill; A determination module is used to construct a communication topology of a roller dynamics model based on graph theory knowledge, and to determine a speed tracking error according to the communication topology; Design module, according to the speed tracking error, design a multi-roller distributed speed tracking control strategy.

9. A six-roller reversible cold rolling mill speed tracking control device, characterized in that: It comprises a processor and a memory, wherein when the processor executes the computer program stored in the memory, the speed tracking control method of the six-roller reversible cold rolling mill as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: Used to store a computer program, wherein when the computer program is executed by a processor, the speed tracking control method for a six-roller reversible cold rolling mill as described in any one of claims 1 to 7 is implemented.

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