A six-high reversible cold rolling mill rotating speed tracking control method, system, device and storage medium

Abstract

The present application relates to the field of distributed control, and specifically relates to a six-roll reversible cold rolling mill speed tracking control method, system, device and storage medium;Including: establish the dynamic model of the leader and the follower, determine the speed tracking error system of the roll, on this basis, use adaptive iterative learning control theory to design the controller and parameter updating law, and estimate unknown parameters by using the parameter updating law.The present application regards each roll of the six-roll reversible cold rolling mill as an intelligent agent, and applies adaptive iterative learning distributed control theory, realizes the distributed collaborative speed tracking control of the roll, and this control mode can adjust the speed of the roll in real time, ensures the coordination and synchronization between the rolls during rolling, thereby significantly improves the rolling precision of the steel, and meets the higher standard production requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of distributed control, in particular to a six-roller reversible cold rolling mill speed tracking control method, system, device and storage medium. BACKGROUND

[0002] Modern steel rolling technology has played an important role in the development of China's industry, and 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 plate processing, six-roller reversible cold rolling mills are the most widely used, including two work rolls, two intermediate rolls and two support rolls. In the rolling process, the speeds of the work rolls, intermediate rolls and support rolls need to be accurately matched. If the speeds of the rolls are not coordinated, it will cause the rolled piece to slide relative to the rolls, affecting the rolling efficiency, and causing 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. However, current speed control in China is often limited to manual adjustment and traditional control methods, which affects equipment operation 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 China has increased, and the old control method cannot meet the new demand. Therefore, in order to improve the quality of rolled steel and reduce the cost of rolling, it is necessary to study the speed coordination control of each roll.

[0003] An agent is an entity with autonomy, interaction and reaction ability, which can perceive the environment, make decisions and execute actions. In a multi-agent system, multiple agents cooperate and compete to achieve common goals. The intelligent beam and extrusion cylinder are regarded as agents, and through the design of control strategy, the agents cooperate with each other to achieve accurate, efficient and stable control in the extrusion process of the extruder.

[0004] Iterative learning control is an intelligent control method, the core idea of which is to use the information in the previous or previous execution process to modify the control input in the current and subsequent execution process by repeatedly executing the same task, so as to achieve complete tracking of the desired trajectory or gradual improvement of control performance. The control law designed by using iterative learning control can effectively improve the accuracy of the production product and reduce the rolling cost. SUMMARY

[0005] In view of the problems mentioned in the prior art, the present application proposes a six-roller reversible cold rolling mill speed tracking control method, system, device and storage medium, which uses intelligent control technology to cooperatively control the relative speed of each roll, so that the speed control precision is higher, the six-roller operation is more stable, and the production process control precision is higher, the stability is stronger, the production efficiency is higher, and the production cost is lower.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] This invention discloses a speed tracking control method for a six-roll reversible cold rolling mill, comprising the following steps:

[0008] Based on the structure of a six-roll reversible cold rolling mill, a roll dynamics model is constructed.

[0009] The communication topology of the roll dynamics model is constructed based on graph theory, and the speed tracking error is determined based on the communication topology.

[0010] Based on the speed tracking error, a multi-roll distributed speed tracking control strategy was designed.

[0011] 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 work roll;

[0012] The follower dynamics model is as follows:

[0013]

[0014] In the formula: yes The first intelligent agent The state variables of the next iteration, where ;; It is the first The first intelligent agent Control input for the next iteration; These are nonlinear disturbance parameters; yes The known local nonlinear functions of Lipschitz are caused by nonlinear factors such as friction, non-uniformity of rolled material, and motor characteristics. It refers to the duration of the rolling process;

[0015] The leader dynamics model is as follows:

[0016]

[0017] In the formula: The working roller speed; The rotational speed curve for rolling steel with work rolls, satisfying ,in It is a positive constant.

[0018] As a further improvement to this invention, the communication topology for constructing the roll dynamics model based on graph theory knowledge includes:

[0019] Construct a weighted adjacency matrix If the node With nodes If there is a communication connection, then , else ;

[0020] Construct a diagonal matrix , where if the th roller is a follower and can directly receive leader information, then , else ;

[0021] Calculate a Laplacian matrix , where ;

[0022] Superimpose the Laplacian matrix and the diagonal matrix to construct a symmetric matrix .

[0023] As a further improvement of the present application, the tracking error system determined according to the communication topology comprises:

[0024] According to the symmetric matrix, establish a uniform error and a general error based on a roller dynamics model,

[0025] The uniform error expression is as follows:

[0026]

[0027] The general error expression is as follows:

[0028]

[0029] In each iteration control, the initial value of the current general error is set as the final value of the previous iteration, i.e. , to obtain the error equation as follows:

[0030]

[0031] The dynamic uniformity control of the roller speed is realized through the error equation.

[0032] As a further improvement of the present application, according to the speed tracking error, a multi-roller distributed speed tracking control strategy is designed, comprising:

[0033] The control input is designed as:

[0034]

[0035] In the formula: is a design parameter that can be adjusted; and are parameter update rates; is a time-varying adjustment gain, and satisfies ; and , ;

[0036] The parameter updating law is designed by a composite energy function:

[0037]

[0038]

[0039] In the formula: 、 The design parameters are adjustable.

[0040] As a further improvement of the application, after obtaining the multi-roller distributed speed tracking control strategy, the multi-roller distributed speed tracking control strategy is verified.

[0041] As a further improvement of the application, when the control input and the parameter updating rate iteration times tend to infinity, the follower agent completely tracks the expected speed trajectory of the leader in the sense of two norms, that is, it satisfies .

[0042] A six-roller reversible cold rolling mill speed tracking control system, comprising:

[0043] A construction module for constructing a roller dynamics model based on the structure of the six-roller reversible cold rolling mill;

[0044] A determination module for constructing a communication topology of the roller dynamics model based on graph theory knowledge, and determining a speed tracking error according to the communication topology;

[0045] A design module for designing a multi-roller distributed speed tracking control strategy according to the speed tracking error.

[0046] A six-roller reversible cold rolling mill speed tracking control device, comprising a processor and a memory, wherein the processor implements the six-roller reversible cold rolling mill speed tracking control method as described above when executing the computer program stored in the memory.

[0047] A computer readable storage medium for storing a computer program, wherein the computer program is executed by a processor to implement the six-roller reversible cold rolling mill speed tracking control method as described above.

[0048] The present application has the following technical effects relative to the prior art:

[0049] The present application regards each roller of the six-roller reversible cold rolling mill as an intelligent agent, and applies adaptive iterative learning distributed control theory to realize distributed collaborative speed tracking control of the rollers. This control method can adjust the speed of the rollers in real time, ensure the coordination and synchronization between the rollers during rolling, and significantly improve the rolling precision of the steel, meeting higher production requirements.

[0050] Compared with the traditional control mode, the self-adjusting ability of the present application, through the autonomous learning and iterative optimization of the intelligent agent, the system can roll the steel with higher precision requirements under the influence of nonlinear factors, ensure the stability and controllability of the rolling process, and improve the production efficiency and product quality.

[0051] The distributed control system of the present application has scalability, and as the production scale changes, the number of intelligent agents can be increased or decreased to adapt to different production demands, and this flexibility enables the present application to be widely applied to cold rolling mill production lines of various scales to meet different production demands. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a schematic diagram of six rollers in the six-roller reversible cold rolling mill of the present application;

[0053] Figure 2 is the communication relationship between the rollers provided for verifying the embodiment of the present application;

[0054] Figure 3 is a schematic diagram of the method flow of the present application. DETAILED DESCRIPTION

[0055] The present application will be further described in detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0056] It should be noted that the mechanical structure of the embodiment of the present application is a six-roller reversible cold rolling mill, and the main research components include the two outermost support rollers, the two middle intermediate rollers, and the two innermost working rollers directly contacting the rolled piece. With the development of modern industry, the demand for rolling mill control precision and stability is increasing. In the rolling process, the two working rollers directly contact the rolled piece and cause plastic deformation of the rolled piece. The working roller rotates to use friction to pull the rolled piece into the roller gap, and under the action of pressure, the thickness of the rolled piece is reduced and the length is increased, thereby realizing the basic function of cold rolling. The intermediate roller is mainly used to adjust the flatness of the rolled piece. By axially moving the intermediate roller, the stress distribution of the working roller can be changed, thereby effectively controlling the flatness of the rolled piece. The main function of the support roller is to provide strong support for the entire rolling process to withstand the huge rolling force. The working states of the six rollers are related to each other and affect the rolling effect of the steel.

[0057] Due to the limitations of manual adjustment and traditional control methods on roll speed control, in the speed control of six-roller, the following one or more types of nonlinear problems may be encountered: the friction force between the roll and the rolled piece is an important factor affecting the roll speed, the friction coefficient is not a fixed value, it will change with the rolling speed, rolling pressure, lubrication conditions and the surface state of the rolled piece and roll, the nonlinear change of the friction coefficient will lead to the change of rolling force and friction force, and then affect the speed of the roll; Nonlinear effects of unevenness of rolled piece material, the rolled piece may have unevenness in material, such as uneven hardness distribution. When the hardness of the rolled piece is different, the bite-in condition of the roll to the rolled piece and the rolling force distribution will change, and the change of rolling force caused by the difference in hardness of the material is nonlinear, because the relationship between hardness change and rolling force is not simply linear, so the roll speed control is more complicated; Nonlinear factors related to motor characteristics, when the motor current increases to a certain extent, the motor core will appear magnetic saturation phenomenon. This will cause the inductance parameter of the motor to change, and then affect the torque output and speed response of the motor. During the long-time operation of the motor, the temperature of the winding will rise. The change of temperature will cause the resistance of the motor winding to increase, thereby affecting the performance of the motor, and then affecting the speed of the roll. The present application only provides theoretical guidance, and the speed control of each roll is considered.

[0058] The present application will be further explained in conjunction with the accompanying drawings and specific embodiments:

[0059] As Figure 1 shown, the six-roller reversible cold rolling mill targeted by the present application can be divided into two multi-agent systems, one work roll, intermediate roll and backup roll as a multi-agent system, the present application only designs a controller for one of the multi-agent systems, the other multi-agent system can be designed according to the same principle, the control target of the present application is to design a distributed speed tracking controller for each roll, to realize:

[0060] ,

[0061] The intermediate roll and backup roll can move accurately under the action of the controller, realize high-precision position and speed control, and maintain the expected relative speed with the work roll; In the present application, is the number of iterations, is the speed of the work roll, i.e. the expected speed, represents the speed state information of the follower, represents the expected relative speed between the follower and the leader.

[0062] Step one, each roller is regarded as an intelligent body, the speed control of multi-roller can be regarded as the speed tracking control problem of multi-intelligent body, through the dynamics research of the roller, the dynamics model of the follower is established, that is, the intermediate roller and the supporting roller, which is expressed as follows:

[0063]

[0064] In the formula: is the state variable of the first iteration of the intelligent body, wherein ; is the control input of the first iteration of the intelligent body; ; is the non-linear disturbance parameter; is the state variable of the first iteration of the intelligent body, wherein ; is the non-linear disturbance parameter; is the known local Lipschitz non-linear function caused by the non-linear factors such as friction, unevenness of the rolled material, motor characteristics and the like; is the duration of the rolling process;

[0065] The leader dynamics model represents the work roller, which is expressed as follows:

[0066]

[0067] In the formula: is the work roller speed; is the speed curve of the work roller when rolling the steel material, satisfying , wherein is a positive constant.

[0068] Step two, the speed control of each roller in the directed graph is considered, as shown in Figure 2 .

[0069] The node relationship in the directed graph is represented by a weighted adjacency matrix, and the weighted adjacency matrix is constructed, wherein if the node has a communication connection with the node , then , otherwise .

[0070] The diagonal matrix is constructed, which is used to represent the communication topological relationship between the follower and the leader, wherein if the roller is a follower and can directly receive the leader information, then , otherwise .

[0071] The Laplacian matrix is calculated, wherein ;​

[0072] The Laplacian matrix is superimposed with a diagonal matrix to construct a symmetric matrix , thereby bridging the consistency error and the general error of the intelligent agent system.

[0073] The consistency error is defined based on the roll dynamics model as follows:

[0074]

[0075] The general error is defined based on the roll dynamics model as follows:

[0076]

[0077] In each iteration control, the initial value of the current general error is set as the final value of the previous iteration, i.e. , and the error equation is obtained as follows:

[0078]

[0079] In the formula: .

[0080] The control target of the application is to design appropriate control input and parameter update law, so that the follower intelligent agent can completely track the leader intelligent agent in the sense of two norms, i.e.

[0081]

[0082] Since the communication of each roll is smooth, i.e. the directed graph between them is connected, then:

[0083]

[0084] Among them, represents the minimum eigenvalue of the symmetric matrix , which can guarantee:

[0085]

[0086] Thus, the convergence of the consistency error is converted into the convergence of the general error.

[0087] Step three, according to the speed tracking error, and selecting a suitable compound energy function, design multi-roll distributed speed tracking control strategy.

[0088] First, according to the speed tracking error, the derivative is as follows:

[0089]

[0090] The compound energy function is selected as follows:

[0091]

[0092] wherein: , , , , , and are adjustable positive constant.

[0093] Taking the derivative, we have:

[0094]

[0095] Since , we have:

[0096]

[0097] wherein, wherein, for a given sequence , we have . Here, Let , we have:

[0098]

[0099] The design control input is:

[0100]

[0101] wherein: is an adjustable design parameter.

[0102] We have:

[0103]

[0104] The design parameter update law:

[0105]

[0106]

[0107] We have:

[0108]

[0109] wherein, the parameter update rate satisfies .

[0110] Step four, for the multi-agent system proposed in the application, the control input Parameter updating law And Guaranteed when the number of iterations tends to infinity, the follower can be in the sense of two norm completely track the leader's desired speed trajectory, that is, complete six roll reversible cold rolling mill speed coordination control ( ).

[0111] This part is a detailed proof of the conclusion, the specific process is as follows:

[0112] Proof: let

[0113] Wherein, .

[0114] From , can be obtained:

[0115]

[0116] Let , then:

[0117]

[0118] Since , then:

[0119]

[0120] Therefore, it can be obtained Bounded. And since , then:

[0121]

[0122] Therefore, it can be obtained , and further .

[0123] Based on the same invention concept, the embodiment of the application also provides a six roll reversible cold rolling mill speed tracking control system, since the principle of the six roll reversible cold rolling mill speed tracking control system solves the problem is similar to the foregoing six roll reversible cold rolling mill speed tracking control method, therefore, the implementation of the six roll reversible cold rolling mill speed tracking control system can be referred to the implementation of the six roll reversible cold rolling mill speed tracking control method, and the repeated parts will not be repeated.

[0124] In specific implementation, the six roll reversible cold rolling mill speed tracking control system provided by the embodiment of the application specifically comprises:

[0125] The construction module is used for constructing the roll dynamics model based on the structure of the six roll reversible cold rolling mill;

[0126] The determining module is configured to determine a communication topology of the roll dynamics model based on graph theory knowledge, and determine the speed tracking error according to the communication topology.

[0127] The designing module is configured to design a multi-roll distributed speed tracking control strategy according to the speed tracking error.

[0128] Correspondingly, the embodiment of the present application further provides a six-roll reversible cold rolling mill speed tracking control device, comprising a processor and a memory, wherein the processor executes the computer program stored in the memory to realize the six-roll reversible cold rolling mill speed tracking control method provided by the embodiment of the present application.

[0129] The more specific process of the above method can refer to the corresponding content disclosed in the foregoing embodiments, which will not be described here.

[0130] Correspondingly, the embodiment of the present application further provides a computer readable storage medium for storing a computer program, wherein the computer program is executed by a processor to realize the above six-roll reversible cold rolling mill speed tracking control method provided by the embodiment of the present application.

[0131] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts of each embodiment can be referred to each other. For the system, device and storage medium disclosed by the embodiments, since it corresponds to the method disclosed by the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0132] The skilled person can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or combination of the two. In order to clearly show the interchangeability of hardware and software, the components and steps of each example have been described in the above description. Whether the functions are realized by hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0133] The steps of the method or algorithm described in combination with the embodiments disclosed herein can be directly implemented by hardware, software module executed by a processor, or combination of the two. The software module can be placed in random access memory (RAM), memory, read only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0134] Finally, it is to be understood that the phraseology or terminology such as "first" and "second" etc. used herein is merely intended to differentiate one entity or operation from another entity or operation, without necessarily requiring or implying any actual such relationship or order between such entities or operations. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0135] The six-high reversible cold rolling mill rotating speed tracking control method, system, device and storage medium provided by the present application are described in detail above, and the principles and implementation manners of the present application are described by applying specific examples in the present article. The above description of the embodiments is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and the above description of the present application should not be understood as a limitation of the present application.

Claims

1. A method for tracking and controlling the speed of a six-roll reversible cold rolling mill, characterized in that, Includes the following steps: Based on the structure of a six-roll reversible cold rolling mill, a roll dynamics model is constructed. The roll dynamics model includes a follower dynamics model and a leader dynamics model, where the follower dynamics model represents the intermediate roll and the support roll, and the leader dynamics model represents the work roll. The follower dynamics model is as follows: In the formula: yes The first intelligent agent The state variables of the next iteration, where ; It is the first The first intelligent agent Control input for the next iteration; These are nonlinear disturbance parameters; yes The known local nonlinear functions of Lipschitz are caused by friction, non-uniformity of rolled material, and nonlinearity of motor characteristics. It refers to the duration of the rolling process; The leader dynamics model is as follows: In the formula: The working roller speed; The rotational speed curve for rolling steel with work rolls, satisfying ,in It is a positive constant; Based on graph theory, a communication topology for the roll dynamics model is constructed, and a weighted adjacency matrix is ​​built. If the node With nodes If a communication connection exists, then ,otherwise ; Construct a diagonal matrix If the first If each roller is a follower and can directly receive information from the leader, then... ,otherwise ; Calculate the Laplace matrix ,in ; Superimpose the Laplacian matrix with the diagonal matrix to construct a symmetric matrix. ; The speed tracking error is determined based on the communication topology; the consistency error and general error based on the roll dynamics model are established based on the symmetric matrix, and the consistency error expression is as follows: In the formula: Indicates the first The expected relative rotational speed between followers and leaders; The general error expression is as follows: In each iteration of control, the initial value of the current general error is set to the final value of the previous iteration, i.e. The error equation is obtained as follows: In the formula: ; Dynamic consistency control of roll speed is achieved through error equations; Based on the speed tracking error, a multi-roll distributed speed tracking control strategy is designed: The control input is designed as follows: for: In the formula: These are adjustable design parameters; and For parameter update rate; The gain is time-varying and satisfies... ;and , ; Designing a parameter update law using a composite energy function: In the formula: , These are adjustable design parameters.

2. The speed tracking control method for a six-roll reversible cold rolling mill according to claim 1, characterized in that, After obtaining the multi-roll distributed speed tracking control strategy, the multi-roll distributed speed tracking control strategy was verified.

3. The speed tracking control method for a six-roll reversible cold rolling mill according to claim 2, characterized in that, When the number of iterations for the control input and parameter update rate approaches infinity, the follower agent completely tracks the leader's desired rotational speed trajectory in the L2 sense, i.e., satisfies... .

4. A speed tracking control system for a six-roll reversible cold rolling mill, applied to the speed tracking control method for a six-roll reversible cold rolling mill as described in any one of claims 1 to 3, characterized in that, include: A module is built to construct a roll dynamics model based on the structure of a six-roll reversible cold rolling mill. The module is used to construct the communication topology of the roll dynamics model based on graph theory knowledge, and to determine the speed tracking error based on the communication topology; The design module, based on the speed tracking error, designs a multi-roll distributed speed tracking control strategy.

5. A speed tracking control device for a six-roll reversible cold rolling mill, characterized in that, It includes a processor and a memory, wherein the processor executes a computer program stored in the memory to implement the six-roll reversible cold rolling mill speed tracking control method as described in any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, Used to store a computer program, wherein the computer program, when executed by a processor, implements the six-roll reversible cold rolling mill speed tracking control method as described in any one of claims 1 to 3.

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