Flow control device and flow control method

Abstract

The present invention provides a flow control device with improved reliability. The flow control device includes: a flow measurement unit for measuring the flow rate of a medicinal liquid in a medicinal liquid supply line; a flow control unit for comparing a preset target flow curve with an application flow curve and controlling the flow rate of the medicinal liquid so that the application flow curve is consistent with the target flow curve; and a processor for switching the flow control unit to a first mode in response to a signal related to the flow rate of the medicinal liquid measured by the flow measurement unit being less than a preset level. In the first mode, the application flow curve includes a curve of a flow estimation model simulated using the flow rate of the medicinal liquid measured by the flow measurement unit.

Description

Technical Field

[0001] The invention relates to a flow control device and a flow control method. Background Art

[0002] Typically, semiconductor and flat panel display manufacturing processes utilize various chemical solutions for deposition, coating, cleaning, and etching processes. These processes utilize chemical solutions such as pure water, etching solutions, developers, and cleaning solutions, as well as mixtures of these solutions. To this end, substrate processing equipment is connected to a chemical supply system to stably receive these various chemical solutions.

[0003] For example, in substrate processing equipment, flow meters are installed on the supply lines connected to the chemical liquid supply system. While there are many different types of flow meters, the most widely used in industrial settings include differential pressure flowmeters, electromagnetic flowmeters, positive displacement flowmeters, and ultrasonic flowmeters. Ultrasonic flowmeters are widely used because they can measure flow rate continuously from outside the meter and offer the same accuracy as electromagnetic flowmeters.

[0004] Ultrasonic flowmeters use an ultrasonic sensor to send and receive ultrasonic signals (or ultrasonic beams) and measure flow velocity by calculating the time difference between them. Ultrasonic flowmeters use this measured flow velocity to measure the flow rate of the fluid. The ultrasonic sensor converts the measured ultrasonic signal into an electrical signal to measure the flow rate. However, in ultrasonic flowmeters, microscopic bubbles contained in the fluid can be trapped around the ultrasonic sensor, particularly at the measurement site where the ultrasonic waves are received. This reduces the sensor's sensitivity and can lead to errors in the measured data. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a flow control device with improved reliability.

[0006] Another technical problem to be solved by the present invention is to provide a flow control method with improved reliability.

[0007] The technical problems of the present invention are not limited to the above-mentioned technical problems, and those skilled in the art can clearly understand other technical problems not mentioned through the following description.

[0008] One aspect of the flow control device of the present invention for solving the above-mentioned technical problems includes: a flow measuring unit for measuring the flow of medicinal liquid in a medicinal liquid supply line; a flow control unit for comparing a preset target flow curve and an application flow curve, and controlling the flow of the medicinal liquid so that the application flow curve is consistent with the target flow curve; and a processor for switching the flow control unit to a first mode in response to a signal related to the flow of the medicinal liquid measured by the flow measuring unit being less than a preset level, wherein in the first mode, the application flow curve includes a curve of a flow estimation model simulated using the flow of the medicinal liquid measured by the flow measuring unit.

[0009] The flow measurement unit includes: a first ultrasonic sensor for oscillating ultrasonic waves in a positive direction relative to the supply direction of the medical liquid at a position corresponding to one end of the medical liquid supply line; and a second ultrasonic sensor for oscillating ultrasonic waves in a reverse direction relative to the supply direction of the medical liquid at a position corresponding to the other end of the medical liquid supply line, wherein the flow measurement unit measures the flow rate of the medical liquid based on ultrasonic signals transmitted and received by the first ultrasonic sensor and the second ultrasonic sensor to each other.

[0010] The flow control unit includes: a PID (Proportional-Integral-Differential) controller for generating a flow control signal based on the difference between the application flow curve and the target flow curve; a current converter for receiving the flow control signal from the PID controller and converting the flow control signal into a valve control current; and a constant pressure valve for adjusting the flow of the liquid medicine based on the valve control current provided by the current converter.

[0011] The processor switches the flow control unit to a second mode in response to a signal related to the flow rate of the medical liquid measured by the flow measurement unit being equal to or greater than the preset level, wherein in the second mode, the application flow curve includes a curve of an actual measured flow rate measured by the flow measurement unit.

[0012] The processor applies a smoothing switching algorithm when switching between the first mode and the second mode.

[0013] The smooth switching algorithm applies a membership function.

[0014] The membership function is designed using the center average method.

[0015] The flow rate estimation model is calculated by applying the flow rate of the chemical liquid measured by the flow rate measurement unit to polynomial regression analysis.

[0016] The flow control device further includes a memory for storing the flow estimation model.

[0017] Another aspect of the flow control device of the present invention for solving the above-mentioned technical problems includes: a flow measuring unit for measuring the flow rate of the medicinal liquid using an ultrasonic sensor; a flow control unit for comparing a preset target flow curve and an application flow curve, and providing a flow control signal to make the application flow curve consistent with the target flow curve; a current converter for converting current according to the flow control signal provided by the flow control unit; and a constant pressure valve for receiving the current provided by the current converter and adjusting the flow rate of the medicinal liquid, wherein the application flow curve includes a curve of a flow estimation model simulated with experimental data of the flow rate of the medicinal liquid in a first mode, and includes a curve of the actual measured flow rate measured by the flow measuring unit in a second mode.

[0018] The flow control device further includes: a processor configured to switch between the first mode and the second mode, wherein the processor applies a smooth switching algorithm to switch between the first mode and the second mode.

[0019] The processor switches to the first mode if a pulse of an ultrasonic signal generated by the ultrasonic sensor is less than a critical value, and switches to the second mode if the pulse of the ultrasonic signal is equal to or greater than the critical value.

[0020] The smooth switching algorithm applies a membership function designed using the mean center method.

[0021] The flow control unit includes a PID controller.

[0022] The flow rate estimation model is calculated by applying the flow rate of the chemical liquid measured by the flow rate measurement unit to polynomial regression analysis.

[0023] One aspect of the flow control method of the present invention for solving the above-mentioned other technical problem includes: measuring the flow rate of the medicinal liquid in the medicinal liquid supply line; comparing the target flow rate curve and the application flow rate curve; and controlling the flow rate of the medicinal liquid so that the application flow rate curve is consistent with the target flow rate curve, wherein the step of controlling the flow rate of the medicinal liquid includes: in response to a signal related to the flow rate of the medicinal liquid being less than a critical level, applying a curve of a flow estimation model simulated using experimental data related to the actually measured flow rate of the medicinal liquid as the application flow rate curve.

[0024] The step of controlling the flow rate of the chemical liquid further includes: in response to the signal related to the flow rate of the chemical liquid being equal to or greater than the critical level, applying a curve of actual measured flow rate obtained by measuring the chemical liquid in the chemical liquid supply line as the applied flow rate curve.

[0025] The step of controlling the flow rate of the liquid medicine further includes applying a smooth switching algorithm when switching the applied flow rate curve between the curve of the flow rate estimation model and the curve of the actual measured flow rate.

[0026] The step of controlling the flow rate of the liquid medicine further includes: switching the applied flow rate curve between the curve of the flow rate estimation model and the curve of the actual measured flow rate within 1 second.

[0027] The steps of controlling the flow rate of the medicinal liquid include: generating a flow control signal based on the difference between the application flow curve and the target flow curve; converting the flow control signal into a valve control current of a corresponding level; and adjusting the flow rate of the medicinal liquid using a constant pressure valve based on the valve control current.

[0028] Details of other embodiments are included in the detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a conceptual diagram for explaining a flow control device according to an embodiment of the present invention.

[0030] Figure 2 FIG. 1 is a diagram illustrating a flow control device according to an embodiment of the present invention.

[0031] Figure 3 FIG. 1 is a diagram illustrating a flow control portion of a flow control device according to an embodiment of the present invention.

[0032] Figure 4 FIG. 1 is a diagram illustrating a flow rate measuring portion of a flow rate control device according to an embodiment of the present invention.

[0033] Figure 5 is a flowchart for explaining the operation of the flow control device according to one embodiment of the present invention.

[0034] Figure 6 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention.

[0035] Figure 7 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention.

[0036] Figure 8FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention.

[0037] Figure 9 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention.

[0038] Figure 10 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention.

[0039] Figure 11 FIG. 1 is a diagram for explaining a flow rate estimation model of a flow rate control device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention and methods for achieving these advantages and features will be described in detail with reference to the accompanying drawings. Figure 1 The present invention will become clear from the detailed description of the embodiments below. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in a variety of different forms. These embodiments are provided only to complete the disclosure of the present invention and to fully inform those skilled in the art of the present invention of the scope of the invention. The present invention is limited only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0041] When an element or layer is referred to as being “on” or “over” another element or layer, it includes not only being directly over the other element or layer but also including the case where other layers or other elements are interposed. In contrast, when an element is referred to as being “directly on” or “over” another element, it means that there are no other elements or layers interposed.

[0042] In order to easily describe the relationship between one element or constituent element and another element or constituent element as shown in the figure, the spatial relative terms "below", "beneath", "lower", "above", "upper", etc. can be used. It should be understood that, in addition to the directions shown in the figures, spatial relative terms are terms that also include different directions of the elements when in use or operation. For example, when the elements shown in the figures are turned over, the element described as "below" or "beneath" another element can be located "above" another element. Therefore, the exemplary term "below" can include both below and above directions. The elements can also be oriented in another direction, whereby the spatial relative terms can be interpreted according to the orientation.

[0043] Although the terms "first," "second," etc. are used to describe various elements, constituents, and / or parts, these elements, constituents, and / or parts are clearly not limited by these terms. These terms are only used to distinguish one element, constituent, and / or part from another element, constituent, and / or part. Therefore, the first element, first constituent, or first part mentioned below may also be the second element, second constituent, or second part within the technical concept of the present invention.

[0044] The terms used in this specification are intended to illustrate the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specified in a sentence, the singular also includes the plural. The use of "comprises" and / or "comprising" in the specification does not exclude the presence or addition of one or more other constituent elements, steps, operations and / or elements in addition to the mentioned constituent elements, steps, operations and / or elements.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with the meanings commonly understood by those skilled in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries shall not be interpreted ideally or excessively unless specifically defined otherwise.

[0046] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals regardless of the reference numerals, and repeated description thereof will be omitted.

[0047] Figure 1 is a conceptual diagram for explaining a flow control device according to an embodiment of the present invention.

[0048] Reference Figure 1 The flow control device 1 controls the flow of the chemical solution provided to the process chamber 10 . Specifically, when the chemical solution supply device 20 supplies the chemical solution to the process chamber 10 , the flow control device 1 controls the flow of the chemical solution in the chemical solution supply line 21 .

[0049] The flow control device 1 controls the flow rate of the chemical solution based on a target flow rate curve required for the process performed in the process chamber 10. When there are multiple chemical solution supply lines 21 supplying the chemical solution to the process chamber 10, multiple target flow rate curves can be used.

[0050] Figure 2 FIG. 1 is a diagram illustrating a flow control device according to an embodiment of the present invention. Figure 3 FIG. 1 is a diagram illustrating a flow control portion of a flow control device according to an embodiment of the present invention. Figure 4 FIG. 1 is a diagram illustrating a flow rate measuring portion of a flow rate control device according to an embodiment of the present invention.

[0051] Reference Figures 2 to 4 The flow control device 1 may include a flow control unit 100 , a flow measurement unit 200 , a processor 300 and a memory 400 .

[0052] The flow rate of the liquid medicine controlled by the flow control device 1 is substantially adjusted and controlled by the flow control unit 100. The flow control unit 100 may include a PID (proportion integral derivation) controller 110, a current converter 120, and a constant pressure valve 130.

[0053] The PID controller 110 compares the target flow rate curve with the application flow rate curve and controls the flow rate of the chemical liquid so that the flow rate of the chemical liquid supplied in the current process is consistent with the target flow rate curve.

[0054] Specifically, the PID controller 110 can perform proportional control, integral control, and differential control. Proportional control calculates a target flow curve and an application flow curve and calculates a controlled variable proportional to their difference. Integral control integrates the deviation when proportional control fails to reach the target value and adds the integral value to the controlled variable. Differential control assigns a controlled variable to the change in the deviation from the target value, enabling the controller to reach the target value more quickly and flexibly.

[0055] A target flow curve may be input into the PID controller 110. The PID controller 110 may provide a flow control signal to the current converter 120 according to the input target flow curve.

[0056] The current converter 120 may receive a flow control signal from the PID controller 110 and convert the current provided to the constant pressure valve 130. That is, the current converter 120 may control the constant pressure valve 130 according to the flow control signal provided from the PID controller 110 by converting the level of the current input to the constant pressure valve 130.

[0057] The constant pressure valve 130 adjusts the flow rate of the liquid medicine based on its opening. The opening of the constant pressure valve 130 can be adjusted by the current level of the current converter 120. Specifically, the flow rate of the liquid medicine can be controlled by receiving air at different pressures and adjusting the opening of the constant pressure valve 130 based on the current level of the current converter 120.

[0058] The constant pressure valve 130 can regulate the flow of the liquid medicine using either a fixed-volume supply method or a feedback supply method. The fixed-volume supply method maintains a constant flow rate by fixing the opening of the constant pressure valve 130. The feedback supply method measures the fluctuating liquid medicine flow rate in real time and adjusts the opening of the constant pressure valve 130 based on the measured value to control the liquid medicine flow rate.

[0059] When real-time control of the flow rate of the supplied liquid medicine is required, the constant pressure valve 130 can control the flow rate of the liquid medicine through a feedback supply method. For example, when the target flow rate curve is not constant and the flow rate changes over time, the constant pressure valve 130 can control the flow rate of the liquid medicine through a feedback supply method to align the application flow rate curve with the target flow rate curve.

[0060] Although Figure 3 Although not shown, the flow control unit 100 may include an electropneumatic regulator. For example, the electropneumatic regulator may be disposed between the current converter 120 and the constant pressure valve 130. The electropneumatic regulator may supply air to the constant pressure valve 130 according to the level of the current supplied from the current converter 120 to adjust the opening of the constant pressure valve 130. The electropneumatic regulator may output air of different pressures based on the magnitude of the analog electrical signal supplied from the current converter 120.

[0061] The flow measurement unit 200 can measure the flow rate of the supplied liquid medicine. In some embodiments, the flow measurement unit 200 can use an ultrasonic flow sensor to measure the flow rate of the liquid medicine. The flow measurement unit 200 can include a first ultrasonic sensor 210 and a second ultrasonic sensor 220.

[0062] The first ultrasonic sensor 210 and the second ultrasonic sensor 220 provide ultrasonic waves to the flowing liquid medicine. The first ultrasonic sensor 210 oscillates ultrasonic waves in a positive direction relative to the liquid medicine supply direction. The first ultrasonic sensor 210 may be located at one end of the liquid medicine supply line 21. The second ultrasonic sensor 220 oscillates ultrasonic waves in a negative direction relative to the liquid medicine supply direction. The second ultrasonic sensor 220 may be located at the other end of the liquid medicine supply line 21. The second ultrasonic sensor 220 can receive the ultrasonic waves oscillated by the first ultrasonic sensor 210, and the first ultrasonic sensor 210 can also receive the ultrasonic waves oscillated by the second ultrasonic sensor 220.

[0063] Flow measurement unit 200 can measure the flow rate of the liquid medicine using the levels of ultrasonic waves transmitted and received by first ultrasonic sensor 210 and second ultrasonic sensor 220. Specifically, the propagation time of the ultrasonic waves provided by first ultrasonic sensor 210 and second ultrasonic sensor 220 through the liquid medicine within liquid medicine supply line 21 can be measured, thereby measuring the flow rate of the liquid medicine using the propagation time and the distance between first ultrasonic sensor 210 and second ultrasonic sensor 220.

[0064] The processor 300 can control the overall operation of the flow control device 1. The processor 300 can control the flow control unit 100, the flow measurement unit 200, and the memory 400. The processor 300 can provide the flow curve provided from the flow measurement unit 200 or the memory 400 to the flow control unit 100 as an application flow curve.

[0065] The memory 400 can store data required by the flow control device 1 to control the flow of the liquid medicine. For example, the memory 400 can store a target flow curve and data related to a flow estimation model that can be used as an application flow curve. The memory 400 can provide the stored data to the processor 300.

[0066] Figure 5 is a flowchart for explaining the operation of the flow control device according to one embodiment of the present invention. Figure 6 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention. Figure 7 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention. Figure 8 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention. Figure 9 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention. Figure 10 FIG. 1 is a diagram for explaining the operation of the flow control device according to an embodiment of the present invention.

[0067] Reference Figure 5 Flow control device 1 measures the actual flow rate of the chemical solution flowing in chemical solution supply line 21 (S100). Next, flow control device 1 generates a signal pulse according to the measured flow rate of the chemical solution in chemical solution supply line 21 (S200).

[0068] Specifically, refer to Figure 4 、 Figure 8 and Figure 9 The flow rate measuring unit 200 of the flow rate control device 1 can measure the flow rate of the chemical solution in the chemical solution supply line 21 .

[0069] When the level of the ultrasonic signals transmitted and received by the first and second ultrasonic sensors 210 and 220 of the flow measurement unit 200 exceeds a critical level Vth, the flow measurement unit 200 may generate a signal pulse regarding the ultrasonic signals transmitted and received by the first and second ultrasonic sensors 210 and 220.

[0070] The flow measurement unit 200 can calculate the flow rate of the medical liquid by considering the time from when the first ultrasonic signal is generated to when the first signal pulse is generated as the time it takes for the medical liquid to move between the first ultrasonic sensor 210 and the second ultrasonic sensor 220. In some embodiments, if the signal pulse occurs three or more times, the flow measurement unit 200 can calculate the flow rate of the medical liquid flowing between the first ultrasonic sensor 210 and the second ultrasonic sensor 220.

[0071] Refer again Figure 5 Then, the flow control device 1 compares the signal pulse generated by the flow measurement unit 200 with a critical value (S300). In some embodiments, the critical value may include three pulses. However, the embodiment is not limited thereto.

[0072] Next, when the signal pulse generated by the flow measurement unit 200 is smaller than the critical value, the flow control device 1 performs smooth switching to switch the mode (S400). Next, the flow control device 1 switches to the first mode (S500).

[0073] Specifically, refer to Figures 6 to 8 When bubbles are present in the liquid medicine flowing between the first ultrasonic sensor 210 and the second ultrasonic sensor 220 of the flow measurement unit 200, the level of the ultrasonic signal transmitted and received by the first ultrasonic sensor 210 and the second ultrasonic sensor 220 does not exceed the critical level Vth. When the level of the ultrasonic signal transmitted and received by the first ultrasonic sensor 210 and the second ultrasonic sensor 220 does not exceed the critical level Vth, the flow measurement unit 200 does not generate a signal pulse. Therefore, when the signal pulse is less than the critical value, the processor 300 can switch the flow control unit 100 to the first mode (Mode 1).

[0074] Smoothing switching is designed to prevent the flow control device 1 from switching modes suddenly, which could cause an incorrect mode. Specifically, in Mode 1, the flow estimation model is compared with the target flow curve as described below. Therefore, if flow control is first performed by comparing the actual measured flow rate with the target flow curve, and then the flow estimation model and target flow curve are compared after switching modes, oscillation or control divergence could occur due to the difference between the actual measured flow rate and the estimated flow rate value from the flow estimation model. Therefore, smooth switching is necessary to avoid abrupt mode switching.

[0075] In some embodiments, the processor 300 can control the flow control unit 100 to perform mode switching using a smooth switching algorithm. The smooth switching algorithm can be designed to apply a membership function to assign weighted values ​​to the switched signals, thereby enabling smooth mode switching within a certain period of time. In addition, the smooth switching algorithm can be designed to minimize the effects of oscillation or control divergence through smooth mode switching.

[0076] In some embodiments, the flow control device 1 can smoothly switch modes within 1 second without error through smooth switching. That is, by using a smooth switching algorithm when switching to the first mode (Mode 1), the flow control device 1 can switch modes without error even if there is a difference between the actually measured flow value and the flow value of the flow estimation model.

[0077] Then, refer to Figure 5 , the flow control device 1 compares the curve of the flow estimation model with the target flow curve ( S600 ).

[0078] Specifically, refer to Figure 8 The processor 300 receives the flow estimation model stored in the memory 400 and provides the flow estimation model as an application flow model to the flow control unit 100. The PID controller 110 may compare the curve of the flow estimation model provided by the processor 300 with the target flow curve. The PID controller 110 may provide a flow control signal to the current converter 120 based on the curve of the flow estimation model to control the flow of the liquid medicine.

[0079] Specifically, the first mode (Mode 1) means that when the flow measurement unit 200 cannot measure the flow rate (for example, when the flowing medical liquid contains bubbles), the flow control device 1 assumes that the flow rate of the supplied medical liquid follows the curve of the flow estimation model. The flow control device 1 controls the flow rate by comparing the flow estimation model with the target flow curve, rather than by comparing the actual measured flow rate with the target flow curve. Therefore, even when the flow rate of the medical liquid cannot be measured, the flow rate can be stably controlled.

[0080] Then, refer again Figure 5 , when the signal pulse is equal to or greater than the critical value, the flow control device 1 switches to the second mode (S700).

[0081] Specifically, refer to Figure 9 and Figure 10 When the signal pulse generated by the flow measurement unit 200 is equal to or greater than the critical value, the processor 300 may switch the flow control unit 100 to the second mode. Figure 5Although the smooth switching when switching to the second mode (Mode 2) is not shown in the figure, the flow control device 1 can also perform smooth switching when switching to the second mode (Mode 2). That is, when switching between the first mode (Mode 1) and the second mode (Mode 2), the flow control device 1 can use a smooth switching algorithm to prevent errors caused by sudden mode switching.

[0082] Then, refer again Figure 5 , the flow control device 1 compares the actual measured flow rate curve measured by the flow measurement unit 200 with the target flow rate curve ( S800 ).

[0083] Specifically, refer to Figure 10 Processor 300 may provide flow control unit 100 with a curve of actual measured flow rates, obtained by directly measuring the flow rate of the supplied liquid medicine by flow measurement unit 200, as an application flow rate curve. PID controller 110 may compare the curve of actual measured flow rates, provided by processor 300 as the application flow rate curve, with the target flow rate curve. PID controller 110 may provide a flow control signal to current converter 120 based on the curve of actual measured flow rates, thereby controlling the flow rate of the liquid medicine.

[0084] That is, the second mode (Mode 2) is a state in which the flow rate of the medicinal liquid can be normally measured by the flow measurement unit 200 (for example, when there are no bubbles in the flowing medicinal liquid), and in the second mode (Mode 2), the flow control device 1 can apply the curve of the actual measured flow rate measured by the flow measurement unit 200 to the application flow curve.

[0085] Figure 11 : is a diagram for explaining a flow estimation model of a flow control device according to an embodiment of the present invention. Specifically, Figure 11 Graph showing how the flow rate of the chemical solution changes according to the level of the current supplied to the constant pressure valve 130 .

[0086] Reference Figure 11 In the first mode (Mode 1), the curve of the flow estimation model that the flow control unit 100 compares with the target flow curve can be generated using experimental data measured by the flow measurement unit 200. Specifically, the flow estimation model can be generated using the flow rate measured by the flow measurement unit 200 based on the current supplied from the current converter 120 to the constant pressure valve 130. That is, the experimental data used to generate the flow estimation model can include the flow rate measured by the flow measurement unit 200 based on the current supplied from the current converter 120 to the constant pressure valve 130.

[0087] In some embodiments, the flow estimation model can be generated by applying a polynomial regression analysis method to experimental data obtained by measuring the flow rate of the liquid medicine. In this case, as the number of polynomial regression analyses increases, the flow estimation model can be closer to the experimental data.

[0088] When generating a flow estimation model, it is necessary to minimize the error in order to improve the accuracy of the flow estimation model. In some embodiments, to minimize the error between the curve of the flow estimation model and the curve of the experimental data, a cost function can be designed and adjusted to bring the curve of the flow estimation model closer to the curve of the experimental data. For example, when using polynomial regression analysis to generate the flow estimation model, the cost function can be used to set the coefficients of the polynomial that minimizes the error between the curve of the flow estimation model and the curve of the experimental data. In addition, a gradient descent algorithm can be used to optimize the cost function.

[0089] While the embodiments of the present invention have been described above with reference to the accompanying drawings, it should be understood by those skilled in the art that the present invention can be implemented in other specific forms without changing its technical concept or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and are not restrictive.

Claims

1. A flow control device comprising: A flow measurement unit, used to measure the flow rate of the liquid medicine in the liquid medicine supply line; a flow control unit, configured to compare a preset target flow curve with an application flow curve, and control the flow rate of the liquid medicine so that the application flow curve is consistent with the target flow curve; as well as a processor configured to switch the flow control unit to a first mode in response to a signal related to the flow rate of the medical liquid measured by the flow measurement unit being less than a preset level, Here, in the first mode, the applied flow rate curve includes a curve of a flow rate estimation model simulated using the flow rate of the chemical liquid measured by the flow rate measurement unit.

2. The flow control device according to claim 1, wherein: The flow measurement unit includes: a first ultrasonic sensor configured to oscillate ultrasonic waves in a positive direction relative to a supply direction of the chemical liquid at a position corresponding to one end of the chemical liquid supply line; and a second ultrasonic sensor configured to oscillate ultrasonic waves in a direction opposite to the supply direction of the liquid medicine at a position corresponding to the other end of the liquid medicine supply line; The flow rate measurement unit measures the flow rate of the chemical liquid based on ultrasonic signals transmitted and received by the first ultrasonic sensor and the second ultrasonic sensor.

3. The flow control device according to claim 1, wherein: The flow control unit includes: a PID controller for generating a flow control signal based on a difference between the application flow curve and the target flow curve; a current converter, configured to receive the flow control signal from the PID controller and convert the flow control signal into a valve control current; and A constant pressure valve is configured to adjust a flow rate of the chemical liquid based on the valve control current supplied from the current converter.

4. The flow control device according to claim 1, wherein: the processor switches the flow control unit to the second mode in response to a signal related to the flow rate of the medical liquid measured by the flow measurement unit being equal to or greater than the preset level; Wherein, in the second mode, the applied flow rate curve includes a curve of an actual measured flow rate measured by the flow rate measurement unit.

5. The flow control device according to claim 4, wherein: The processor applies a smooth switching algorithm when switching between the first mode and the second mode. The flow control device according to claim 5 , wherein the smooth switching algorithm applies a membership function.

7. The flow control device according to claim 6, wherein: The membership functions are designed using the mean center method.

8. The flow control device according to claim 1, wherein: The flow rate estimation model is calculated by applying the flow rate of the chemical liquid measured by the flow rate measurement unit to a polynomial regression analysis.

9. The flow control device according to claim 1, further comprising: A memory is used to store the flow estimation model.

10. A flow control device comprising: A flow measurement unit, used to measure the flow rate of the liquid medicine using an ultrasonic sensor; a flow control unit, configured to compare a preset target flow curve with an application flow curve, and provide a flow control signal to make the application flow curve consistent with the target flow curve; a current converter, configured to convert current according to the flow control signal provided by the flow control unit; as well as a constant pressure valve, for receiving the current provided by the current converter and regulating the flow of the liquid medicine; The applied flow rate curve includes a curve of a flow rate estimation model simulated using experimental data of the flow rate of the medical liquid in the first mode, and includes a curve of an actual measured flow rate measured by the flow rate measurement unit in the second mode.

11. The flow control device according to claim 10, further comprising: a processor, configured to switch between the first mode and the second mode, The processor applies a smooth switching algorithm to switch between the first mode and the second mode.

12. The flow control device according to claim 11, wherein: The processor switches to the first mode if a pulse of an ultrasonic signal generated by the ultrasonic sensor is less than a critical value, and switches to the second mode if the pulse of the ultrasonic signal is equal to or greater than the critical value.

13. The flow control device according to claim 11, wherein: The smooth switching algorithm applies a membership function designed using the mean center method.

14. The flow control device according to claim 10, wherein: The flow control unit includes a PID controller.

15. The flow control device according to claim 10, wherein: The flow rate estimation model is calculated by applying the flow rate of the chemical liquid measured by the flow rate measurement unit to polynomial regression analysis.

16. A flow control method comprising the following steps: Measuring the flow rate of the liquid medicine in the liquid medicine supply line; Compare the target flow curve and the application flow curve; as well as Controlling the flow rate of the liquid medicine so that the application flow curve is consistent with the target flow curve, Among them, the step of controlling the flow rate of the medicinal liquid includes: in response to a signal related to the flow rate of the medicinal liquid being less than a critical level, applying a curve of a flow estimation model simulated using experimental data related to the actually measured flow rate of the medicinal liquid as the applied flow curve.

17. The flow control method according to claim 16, wherein: The step of controlling the flow rate of the chemical liquid further includes: in response to the signal related to the flow rate of the chemical liquid being equal to or greater than the critical level, applying a curve of actual measured flow rate obtained by measuring the chemical liquid in the chemical liquid supply line as the applied flow rate curve.

18. The flow control method according to claim 17, wherein: The step of controlling the flow rate of the liquid medicine further includes applying a smooth switching algorithm when switching the applied flow rate curve between the curve of the flow rate estimation model and the curve of the actual measured flow rate.

19. The flow control method according to claim 17, wherein: The step of controlling the flow rate of the liquid medicine further includes: switching the applied flow rate curve between the curve of the flow rate estimation model and the curve of the actual measured flow rate within 1 second.

20. The flow control method according to claim 16, wherein: The step of controlling the flow rate of the liquid medicine comprises: generating a flow control signal according to a difference between the application flow curve and the target flow curve; converting the flow control signal into a valve control current of a level corresponding thereto; and Based on the valve control current, a constant pressure valve is used to adjust the flow rate of the chemical solution.

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