Butterfly valve and pressure control method thereof

Abstract

The invention relates to the technical field of valve control, and discloses a butterfly valve and a pressure control method thereof.The method comprises the steps that the butterfly valve is started multiple times, data of the pressure, the opening degree and the air exhaust rate of a plurality of sets of butterfly valves are obtained, and a three-dimensional power function model is established based on the pressure opening degree and the air exhaust rate; the pressure of the butterfly valve is collected in real time for multiple times in the opening and closing process of the butterfly valve, and the pressure change rate is calculated; the target pressure of the butterfly valve is set, and the ideal pressure change buffering rate of the butterfly valve is calculated based on the collected current pressure of the butterfly valve; calculating the opening degree of the butterfly valve under the target pressure; and the butterfly valve is controlled to move to the calculated target opening degree to complete control adjustment of the butterfly valve. Pressure data are collected in real time; updating butterfly valve air exhaust model parameters in a learning mode; calculating the position of a target valve and adjusting in advance; and system parameters are continuously optimized, and high precision and quick response capability of the system are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of valve control, and in particular to a butterfly valve and a pressure control method thereof. Background Art

[0002] In the fields of semiconductor manufacturing, thin film deposition, surface science experiments, and precision instrument processing, precise high-vacuum pressure control is crucial. Currently, the butterfly valve control method usually adopts traditional PID control or open-loop regulation of empirical parameters based on simple PID or fixed-value regulation methods, ignoring the nonlinear pumping characteristics of the system and the influence of leakage on control, and failing to effectively cope with the nonlinear characteristics of chamber gas leakage and butterfly valve pumping, resulting in limited pressure control accuracy, slow response, large overshoot, and significant steady-state error. Summary of the Invention

[0003] To solve the above problems, the technical solution adopted by the present invention is as follows: A pressure control method for a butterfly valve, comprising the following steps: S1. Start the butterfly valve multiple times, and obtain data of the pressure, opening degree, and pumping rate of the butterfly valve in several groups, and establish a three-dimensional power function model based on the pressure opening degree and pumping rate: where r is the pumping rate, P is the pressure, x is the opening degree, and A, α, and β are the fitting parameters of the three-dimensional power function; S2. Start the butterfly valve once, and collect the pressure P(t) of the butterfly valve in real time multiple times during the opening and closing process of the butterfly valve, and calculate the pressure change rate : S3. Obtain the inflation rate of the butterfly valve based on the pressure change rate : ; where r pump is the change rate of the influence of pumping on pressure corresponding to the current pressure and opening degree; S4. Set the target pressure P target of the butterfly valve based on the three-dimensional power function model, and calculate the ideal pressure change buffer rate of the butterfly valve based on the currently collected pressure P of the butterfly valve: ; S5. Calculate the opening degree of the butterfly valve under the target pressure: Control the butterfly valve to move to the calculated target opening degree to complete the control adjustment of the butterfly valve; S6. After the butterfly valve stabilizes, collect the data of the butterfly valve in real time, and compare the difference between the current pressure P of the collected butterfly valve and the target pressure P target with the set threshold. If the difference is less than the set threshold, the adjustment of the butterfly valve is completed; if the difference is greater than the set threshold, repeat steps S4 and S5.

[0004] Furthermore, in step S1, logarithmic transformation linear regression is also included for the three-dimensional power function model: Convert the three-dimensional power function into multiple linear regression, and use the least squares method to efficiently solve the parameters A, α, and β.

[0005] Furthermore, in step S3, smoothing processing is also included: where is the true inflation rate of the butterfly valve, is the smoothing factor with a value range of 0.1 - 0.3, is the set historical inflation rate.

[0006] Furthermore, in step S4, working condition correction is also included for the ideal pressure change buffering rate: where, represents the corrected air extraction rate, and κ(P, e) is a correction coefficient , and e is an error term.

[0007] A butterfly valve includes an installation box, a driving motor, and a sealing disc. The driving motor is installed inside the installation box. A connecting pipe is provided on the side of the installation box. The output shaft of the driving motor penetrates the side of the installation box and extends into the connecting pipe. The connecting pipe is used to communicate with a vacuum chamber. A sealing disc is fixedly connected to the output shaft of the driving motor. The sealing disc is located in the connecting pipe and is adapted to seal with the connecting pipe.

[0008] Furthermore, a control circuit board is installed in the installation box. The control circuit board is electrically connected to the driving motor and is used to control the working state of the driving motor.

[0009] Furthermore, a sealing ring is provided on the circumferential side surface of the sealing disc, and when the sealing disc seals with the connecting pipe, the sealing ring fits with the side wall of the connecting pipe.

[0010] Furthermore, the cross-section of the joint between the connecting pipe and the sealing disc is conical.

[0011] Advantages of the present invention: The present invention collects pressure data in real time; dynamically updates the parameters (A, α, β) of the butterfly valve air extraction model; calculates the target valve position and adjusts it in advance; performs PID fine adjustment when approaching the target; continuously optimizes the system parameters to ensure the high precision and fast response ability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings herein are incorporated into and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present invention.

[0013] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0014] Figure 1 is a schematic structural diagram of a butterfly valve; Figure 2 is a partial structural diagram of a butterfly valve; Figure 3 is a cross-sectional view of a connecting pipe.

[0015] In the figure: 1, mounting box; 2, drive motor; 3, sealing disc; 4, connecting pipe; 5, control circuit board DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the following will clearly and completely describe the technical solutions of the embodiments of the present disclosure with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the described embodiments of the present disclosure belong to the scope of protection of the present disclosure.

[0017] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should have the ordinary meaning understood by those of ordinary skill in the art in the field to which the present disclosure belongs. The "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0018] Embodiment 1. A pressure control method for a butterfly valve, comprising the following steps: In the formula, r is the pumping rate, P is the pressure, x is the opening degree, and A, α, and β are the fitting parameters of the three-dimensional power function.

[0019] In actual operation, since the three-dimensional power function itself is non-linear, direct fitting is relatively complex, which will reduce the processing efficiency and affect the real-time performance of valve control. Therefore, in order to improve the processing efficiency, logarithmic transformation linear regression is performed on the three-dimensional power function model: Converting the three-dimensional power function into a multiple linear regression can directly use the least squares method to efficiently solve the parameters A, α, and β, avoiding the complex iterative process of non-linear optimization algorithms and improving the efficiency of parameter calculation. In addition, the data of the three-dimensional power function may have heteroscedasticity (the variance increases with the increase of the variable) or outliers. The logarithmic transformation weakens the interference of these problems on the model by compressing the data scale and reducing the order of magnitude difference between large values and small values.

[0020] Step S2: Start the butterfly valve once, and collect the pressure P(t) of the butterfly valve in real time multiple times during the opening and closing process of the butterfly valve, and calculate the pressure change rate : Step S3: Obtain the inflation rate of the butterfly valve based on the pressure change rate :

[0021] where r pump is the change rate of the influence of pumping on the pressure corresponding to the current pressure and opening degree.

[0022] In step S3, when obtaining information such as the pressure of the butterfly valve through the sensor, instantaneous noise such as equipment jitter and environmental interference will generate calculation errors. Therefore, it is also necessary to smooth the inflation rate to weaken the influence of single measurement noise. The formula for smoothing is as follows: where is the true inflation rate of the butterfly valve, is the smoothing factor with a value range of 0.1 - 0.3, is the set historical inflation rate.

[0023] Step S4: Set the target pressure P target of the butterfly valve based on the three-dimensional power function model, and calculate the ideal pressure change buffer rate of the butterfly valve based on the currently collected pressure P of the butterfly valve: Among them is a time coefficient used to adjust the strength of the change buffer.

[0024] In the actual production process, the system is often interfered by external factors such as temperature, pressure, and load. The changes of these factors will directly affect the dynamic performance of the system. Therefore, in step S4, it is also necessary to correct the operating conditions of the ideal pressure change buffer rate: Among them, represents the corrected extraction rate, and κ(P, e) is a correction coefficient , and e is an error term.

[0025] Step S5: Calculate the opening degree of the butterfly valve under the target pressure : Control the butterfly valve to move to the calculated target opening degree Complete the control adjustment of the butterfly valve.

[0026] Step S6: After the butterfly valve is stable, collect the data of the butterfly valve in real time, and compare the difference between the current pressure P of the collected butterfly valve and the target pressure P target with the set threshold. If the difference is less than the set threshold, the adjustment of the butterfly valve is completed. If the difference is greater than the set threshold, repeat step S4 and step S5.

[0027] The present invention collects pressure data in real time; dynamically updates the parameters (A, α, β) of the butterfly valve extraction model; calculates the target valve position and adjusts it in advance; performs PID fine adjustment when approaching the target; continuously optimizes the system parameters to ensure the high precision and fast response ability of the system.

[0028] A butterfly valve, as Figures 1-3 shown, includes an installation box 1, a driving motor 2, and a sealing disc 3. The driving motor 2 is installed inside the installation box 1. A connecting pipe 4 is provided on the side of the installation box 1. The output shaft of the driving motor 2 penetrates through the side of the installation box 1 and extends into the connecting pipe 4. The connecting pipe 4 is used to communicate with the vacuum chamber. A sealing disc 3 is fixedly connected to the output shaft of the driving motor 2. The sealing disc 3 is located in the connecting pipe 4 and is adapted to seal with the connecting pipe 4.

[0029] The circumferential side surface of the sealing disc 3 is provided with a sealing ring, and when the sealing disc 3 is sealed with the connecting pipe 4, the sealing ring is in contact with the side wall of the connecting pipe 4. The cross-section of the joint between the connecting pipe 4 and the sealing disc 3 is conical. When the sealing disc 3 is sealed with the connecting pipe 4, the conical connecting pipe 4 can reduce the contact area between the sealing ring and the connecting pipe 4, thereby increasing the pressure and ensuring the sealing performance between the sealing disc 3 and the connecting pipe 4. At the same time, the conical connecting pipe 4 also facilitates the rotation of the sealing disc 3.

[0030] A control circuit board 5 is installed in the installation box 1. The control circuit board 5 is electrically connected to the driving motor 2. The control circuit board 5 is used to control the working state of the driving motor 2, and thus control the sealing disc 3, that is, the opening degree of the butterfly valve. The control circuit board 5 controls the opening degree of the sealing disc 3 by controlling the rotation angle of the driving motor 2.

[0031] Unless otherwise defined, in the embodiments of the present disclosure and the accompanying drawings, the same reference numerals represent the same meaning.

[0032] In the accompanying drawings of the embodiments of the present disclosure, only the structures related to the embodiments of the present disclosure are involved, and other structures can refer to the general design.

[0033] For clarity, in the drawings used to describe the embodiments of the present disclosure, components or regions are enlarged. It can be understood that when an element is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element, or there can be intermediate elements.

[0034] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present disclosure, and all of them should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A pressure control method for a butterfly valve, characterized in that: It includes the following steps: S1. Start the butterfly valve multiple times, obtain data of the pressure, opening degree, and air extraction rate of several groups of butterfly valves, and establish a three-dimensional power function model based on the pressure opening degree and air extraction rate: In the formula, r is the air extraction rate, P is the pressure, x is the opening degree, and A, α, and β are the fitting parameters of the three-dimensional power function; S2. Start the butterfly valve once and collect the pressure P(t) of the butterfly valve in real time multiple times during the opening and closing process of the butterfly valve, and calculate the pressure change rate : S3. Obtain the inflation rate of the butterfly valve based on the pressure change rate : ； where r pump is the rate of change of the influence of the air extraction on the pressure corresponding to the current pressure and opening degree; S4. Set the target pressure P of the butterfly valve based on the three-dimensional power function model target , and calculate the ideal pressure change buffering rate of the butterfly valve based on the currently collected pressure P of the butterfly valve : ； S5. Calculate the opening degree of the butterfly valve under the target pressure : Control the butterfly valve to move to the calculated target opening Complete the control adjustment of the butterfly valve; S6. After the butterfly valve stabilizes, collect the data of the butterfly valve in real time, and compare the difference between the current pressure P of the collected butterfly valve and the target pressure P target with the set threshold value. If the difference is less than the set threshold value, the adjustment of the butterfly valve is completed. If the difference is greater than the set threshold value, repeat steps S4 and S5.

2. A pressure control method for a butterfly valve according to claim 1, characterized in that: In step S1, logarithmic transformation linear regression is also included for the three-dimensional power function model: Convert the three-dimensional power function into multiple linear regression, and use the least squares method to efficiently solve the parameters A, α, and β.

3. A pressure control method for a butterfly valve according to claim 1, characterized in that: In step S3, smoothing processing is also included: wherein is the true inflation rate of the butterfly valve, is the smoothing factor with a value range of 0.1 - 0.3, is the set historical inflation rate.

4. A pressure control method for a butterfly valve according to claim 1, characterized in that: In step S4, working condition correction is also included for the ideal pressure change buffering rate: Among them, represents the corrected pumping rate, and κ(P,e) is a correction coefficient , and e is an error term.

5. A butterfly valve for implementing the pressure control method of a butterfly valve according to any one of claims 1-4, characterized in that: It includes an installation box (1), a driving motor (2), and a sealing disc (3). The driving motor (2) is installed inside the installation box (1). A connecting pipe (4) is provided on the side of the installation box (1). The output shaft of the driving motor (2) penetrates through the side of the installation box (1) and extends into the connecting pipe (4). The connecting pipe (4) is used to communicate with the vacuum chamber. The sealing disc (3) is fixedly connected to the output shaft of the driving motor (2). The sealing disc (3) is located in the connecting pipe (4) and is adapted to be sealed with the connecting pipe (4).

6. A butterfly valve according to claim 5, characterized in that: A control circuit board (5) is installed in the installation box (1). The control circuit board (5) is electrically connected to the driving motor (2), and the control circuit board (5) is used to control the working state of the driving motor (2).

7. A butterfly valve according to claim 5, characterized in that: A sealing ring is provided on the circumferential side of the sealing disc (3), and when the sealing disc (3) is sealed with the connecting pipe (4), the sealing ring fits with the side wall of the connecting pipe (4).

8. A butterfly valve according to claim 7, characterized in that: The cross-section of the fitting portion of the connecting pipe (4) and the sealing disc (3) is conical.

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