Cooperative control method and system for sensor automatic calibration production line
By constructing a fluid network model and a feedforward flow compensation mechanism, the problems of gas transmission lag and pressure coupling interference in the automated sensor calibration production line were solved, achieving precise gas control and accurate data acquisition, and improving production efficiency and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-05
- Publication Date
- 2026-04-07
AI Technical Summary
Existing automated sensor calibration production lines suffer from control deviations caused by pipeline transmission lag, interference from pressure coupling in multiple calibration chambers, and data mis-sampling caused by false steady-state conditions.
By constructing a physical model of the fluid network, calculating the gas transport lag time, and utilizing feedforward flow compensation and countdown locking mechanisms, precise gas control and data acquisition are achieved.
It eliminates the trailing effect caused by the inherent volume of the pipeline, improves production efficiency, ensures the authenticity and validity of the data, and enhances the stability of parallel calibration of multiple calibration chambers.
Smart Images
Figure CN121806649A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of industrial automation control technology, specifically to a collaborative control method and system for sensor automated calibration production lines. Background Technology
[0002] As a core component of industrial safety monitoring, the calibration process of gas sensors before they leave the factory is crucial. The calibration process requires placing the sensor in a specific temperature and humidity environment and introducing a standard gas of precise concentration (such as carbon monoxide, methane, etc.) to calibrate its zero point and sensitivity. In order to meet the needs of large-scale production, modern production lines usually adopt a "centralized gas supply and multiple calibration chambers in parallel" architecture, which simultaneously supplies gas to multiple calibration chambers located in different physical locations through a central gas distribution system.
[0003] However, this architecture has the following drawbacks in actual operation. First, there are pipelines of varying lengths from the gas distribution center to each calibration chamber. The inherent volume of the pipelines causes a significant time lag in gas transmission. Existing feedback control strategies based on PID control algorithms rely on changes in sensor readings to adjust the flow rate. When the concentration changes rapidly, this physical lag cannot be overcome, resulting in slow response and seriously affecting the production line cycle time. Second, the shared gas source among multiple calibration chambers causes pressure coupling interference. When a calibration chamber adjusts the flow rate or switches a valve, it will cause pressure fluctuations in the main pipeline, which in turn will interfere with other calibration chambers that are undergoing steady-state testing, causing data jumps.
[0004] Most importantly, existing technologies typically rely solely on the fluctuation rate of sensor readings to determine steady state. In the early stages of gas replacement, before the old gas has been emptied and the new gas wavefront has arrived, the sensor readings may temporarily remain stable. The system is highly susceptible to misjudging that the target environment has been reached and thus sampling. This false steady state can lead to the entry of invalid data, resulting in product misjudgment or rework.
[0005] Therefore, there is an urgent need for a control method that can overcome pipeline lag, eliminate coupling interference, and accurately identify steady state. Summary of the Invention
[0006] To address the issues of control deviations caused by pipeline transmission lag, pressure coupling interference from multiple calibration chambers, and data mis-acquisition due to spurious steady-state conditions, this invention proposes a collaborative control method and system for automated sensor calibration production lines.
[0007] In a first aspect, the present invention provides a collaborative control method for an automated sensor calibration production line, the method comprising: During the operation of the sensor automated calibration production line, basic physical parameters and dynamic fluid state data of the fluid network are collected. The fluid network includes a common gas distribution main pipeline and branch gas supply pipelines connecting the common gas distribution main pipeline and the calibration chamber. The basic physical parameters include the physical dimension information of the branch gas supply pipelines, and the dynamic fluid state data includes the average absolute pressure in the common gas distribution main pipeline and the instantaneous volumetric flow rate in the branch gas supply pipelines. Based on the physical dimensions of the branch gas pipeline and the average absolute pressure, the total physical amount of gas retained in the branch gas pipeline is determined. Combined with the instantaneous volumetric flow rate and the preset equivalent diffusion bias flow rate, a gas transmission lag model is constructed. The gas transmission lag model is used to calculate the dynamic transmission lag time of the new gas wavefront arriving at the calibration chamber. In response to the concentration switching command of the automated calibration line, the concentration difference between the target set concentration and the actual concentration in the calibration chamber is calculated. Based on the concentration difference, the basic flow rate adjustment is determined. The basic flow rate adjustment is adaptively modulated using the dynamic transmission lag time to generate a feedforward flow compensation for the calibration chamber. The feedforward flow compensation is then superimposed with the basic set flow rate to generate a flow control command to control the main pipeline flow controller.
[0008] This technical solution no longer blindly waits for the sensor's delayed feedback. Instead, it constructs a fluid dynamics model of the physical pipeline to predict the gas transmission behavior in real time. By calculating the dynamic transmission lag time, the system can accurately determine the moment when the new gas arrives at the calibration chamber, thereby providing the optimal flushing flow rate at the instant the gas arrives. This eliminates the tailing effect caused by the dead volume of the pipeline. This feedforward control based on the physical model shortens the steady-state establishment time of the gas concentration switching process, achieves accurate collaborative control, and improves production efficiency.
[0009] Preferably, determining the total physical volume of gas retained in the branch gas pipeline based on the physical dimensions of the branch gas pipeline and the average absolute pressure includes: obtaining the physical length and inner diameter cross-sectional area of the branch gas pipeline, multiplying the two to obtain the geometric internal volume of the branch gas pipeline; using the average absolute pressure to perform density correction on the geometric internal volume, calculating the total volume of standard gas actually contained inside the branch gas pipeline under the current pressure state, and determining this total volume as the total physical volume of gas retained in the branch gas pipeline.
[0010] Preferably, a gas transport lag model is constructed, and the dynamic transport lag time of the new gas wavefront reaching the calibration chamber is calculated using the gas transport lag model. This includes: taking the total physical amount of gas retained in the branch gas supply pipeline as the numerator; taking the sum of the instantaneous volumetric flow rate in the branch gas supply pipeline flowing to the calibration chamber and the equivalent diffusion bias flow rate as the denominator; calculating the ratio of the numerator to the denominator to obtain the time required for the new gas wavefront to physically transport from the common gas distribution pipeline to the calibration chamber, and determining it as the dynamic transport lag time; wherein, the equivalent diffusion bias flow rate is used to characterize the natural diffusion effect of the gas and prevent the denominator from being zero.
[0011] This technical solution fully considers the characteristics of gas as a compressible fluid. When the pipeline pressure increases, the gas density increases and the molecular density becomes higher, which leads to a longer replacement time. By introducing real-time pressure parameters and equivalent diffusion bias flow, the model can accurately describe the transmission lag under different operating conditions, ensuring the accuracy and robustness of the prediction.
[0012] Preferably, calculating the concentration difference between the target set concentration and the actual concentration in the calibration chamber, and determining the basic flow rate adjustment based on the concentration difference, includes: obtaining the target set concentration specified for the calibration chamber in the concentration switching instruction, reading the current actual concentration before the concentration switching, calculating the absolute value of the difference between the two; setting a feedforward gain coefficient, multiplying the absolute value of the difference by the feedforward gain coefficient to obtain the initial flow rate value used to drive rapid gas replacement, and determining it as the basic flow rate adjustment.
[0013] Preferably, the basic flow rate adjustment is adaptively modulated using the dynamic transmission lag time to generate a feedforward flow rate compensation for the calibration chamber, including: setting a maximum allowable response time constant for the system; constructing an exponential function with a natural constant as the base, the exponent of which is composed of the negative of the ratio of the maximum response time constant to the dynamic transmission lag time; calculating a modulation factor using the exponential function, the modulation factor being negatively correlated with the dynamic transmission lag time; and multiplying the basic flow rate adjustment by the modulation factor to obtain the final applied flow rate correction value, which is determined as the feedforward flow rate compensation for the calibration chamber.
[0014] This technical solution implements an adaptive control strategy. For short pipelines with short lag times, the system applies full compensation to achieve rapid switching. For long pipelines with long lag times, the exponential part automatically suppresses the compensation intensity to prevent water hammer effect and end overshoot caused by excessive flow pulses. This mechanism balances response speed and system stability, and realizes coordinated control of calibration chambers at different distances.
[0015] Preferably, generating a flow control command to control the main pipeline flow controller includes: superimposing the feedforward flow compensation values of all calibration chambers to obtain a compensation flow term; superimposing the basic set flow values of all calibration chambers to obtain a basic flow term; using the sum of the compensation flow term and the basic flow term as the final flow command; sending the final flow control command to the main pipeline flow controller; simultaneously generating an exhaust control signal using the compensation flow term to control the opening of the exhaust valve arranged in the common gas distribution main pipeline, so that it maintains a linear following adjustment relationship with the compensation flow term; when the compensation flow term is positive, synchronously and linearly increasing the opening of the exhaust valve; when the compensation flow term is zero, maintaining the opening of the exhaust valve.
[0016] This technical solution achieves a balance between rapid gas replacement and maintaining stable calibration chamber pressure by constructing a synchronous linkage mechanism for intake and exhaust. While the system adds the feedforward compensation to the base flow to accelerate the flushing of the pipeline lag, it forces the exhaust valve to perform linear follow-up adjustment. This means that when the intake flow surges instantaneously due to compensation demand, the exhaust channel can expand synchronously and proportionally. This bidirectional coordinated airflow strategy does not passively wait for the pressure to rise before adjusting, but rather physically counteracts the pressure stagnation or pressure oscillation in the calibration chamber that may be caused by sudden changes in intake. It achieves a significant reduction in steady-state establishment time while dynamically maintaining the gas pressure balance inside the calibration chamber, ensuring that the precision sensor always operates under a constant pressure environment and eliminating the risk of reading drift caused by pressure shocks.
[0017] Preferably, while generating flow control commands to control the main pipeline flow controller, a countdown locking mechanism is also activated, including: starting a countdown timer while issuing a concentration switching command, setting the initial time of the countdown timer to the dynamic transmission lag time; monitoring the remaining time of the countdown timer in real time, and if the remaining time is greater than zero, determining that the gas transmission stage is in progress, and disabling the data acquisition function of the sensor in the calibration chamber; when the remaining time of the countdown timer reaches zero, determining that the wavefront of the new gas has arrived in the calibration chamber, removing the shield, and restoring the data acquisition function of the sensor.
[0018] This technical solution strictly distinguishes between the transmission and diffusion stages through a countdown locking mechanism. Before the system physically confirms the arrival of new gas, it refuses to collect any seemingly stable sensor readings. This mechanism avoids the risk of false steady-state misjudgment caused by residual old gas, ensuring the authenticity and validity of the calibration data finally collected by the sensor.
[0019] Preferably, after the sensor's data acquisition function is restored, the following operation is performed: the real-time reading of the sensor is acquired immediately, allowing the system to formally input the calibration data acquired by the sensor.
[0020] Preferably, before collecting the basic physical parameters and dynamic fluid state data of the fluid network, the method further includes: establishing a physical mapping relationship of the fluid network in the configuration database of the control system, and pre-storing the geometric and physical parameters of each calibration chamber of the automated calibration production line; the geometric and physical parameters include: the physical length of the branch gas transmission pipeline, the inner diameter cross-sectional area of the branch gas transmission pipeline, and the effective volume of the calibration chamber itself; collecting the real-time average absolute pressure of the common gas distribution main pipeline through sensors arranged on the common gas distribution main pipeline; and collecting the instantaneous volumetric flow rate of the branch gas transmission pipeline flowing to each calibration chamber through sensors arranged on each of the branch gas transmission pipelines.
[0021] The present invention also provides a collaborative control system for an automated sensor calibration production line, the collaborative control system including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of any collaborative control method.
[0022] The present invention has the following effects: This invention introduces dynamic lag time calculation to accurately predict the gas arrival time. Combined with feedforward flow compensation, it provides the optimal flushing flow rate at the moment of gas arrival, eliminating the tailing effect caused by the inherent volume of the pipeline. The data acquisition locking mechanism based on the physical model eliminates false steady-state misjudgment, suppresses pressure fluctuations in long pipelines, enhances the stability of parallel calibration of multiple calibration chambers, and improves the accuracy of collaborative control. Attached Figure Description
[0023] Figure 1 This is a flowchart of the present invention; Figure 2 This is a comparison chart of gas concentration control response data under the collaborative feedforward control of the present invention and existing technologies; Figure 3 It is a graph showing the change in the main pipeline gas flow command before and after coordinated compensation. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
[0025] Reference Figure 1 The present invention provides a collaborative control method for an automated sensor calibration production line, comprising: S1: During the operation of the sensor automated calibration production line, collect the basic physical parameters and dynamic fluid state data of the fluid network.
[0026] A fluid network refers to the pipeline topology constructed in an automated sensor calibration production line to transport standard gas from a central gas distribution system to calibration chambers located at various physical positions. This network is physically defined as a common main gas distribution pipeline providing a pressure reference and branch gas delivery pipelines connecting the main pipeline to each independent calibration chamber. This fluid network is not a simple gas channel, but a compressible fluid system with a defined geometric internal volume. The fundamental physical parameters and dynamic fluid state data of the fluid network jointly determine the physical behavior of gas transmission, forming the physical basis for constructing gas transmission lag models, calculating dynamic transmission lag times, and realizing collaborative feedforward control of multiple calibration chambers. The fundamental physical parameters include the physical dimensions of the branch gas delivery pipelines, and the dynamic fluid state data includes the average absolute pressure within the common main gas distribution pipeline and the instantaneous volumetric flow rate within the branch gas delivery pipelines.
[0027] Before the automated calibration production line is started, the physical mapping relationship of the fluid network is established through the configuration database of the control system, and the geometric and physical parameters of each calibration chamber of the automated calibration production line are stored in advance. The geometric and physical parameters include: the physical length of the branch gas supply pipeline, the inner diameter cross-sectional area of the branch gas supply pipeline, and the effective volume of the calibration chamber itself. The real-time average absolute pressure of the common gas distribution main pipeline is collected by sensors arranged on the common gas distribution main pipeline. The instantaneous volumetric flow rate of the branch gas supply pipeline flowing to each calibration chamber is collected by sensors arranged on each of the branch gas supply pipelines.
[0028] Assuming the production line has a total of The calibration chamber, for the first Each calibration chamber is defined as having a physical length of the branch gas pipeline connecting to the main gas distribution valve. (Unit: meters), the inner diameter cross-sectional area of this branch gas pipeline is... (Unit: square meters), this value is determined by the pipe diameter and the effective volume of the calibration chamber itself. .
[0029] Next, dynamic fluid state data is collected in real time using high-frequency sensors deployed on the pipeline, including the average absolute pressure within the common gas distribution main pipeline. (Unit: Pascal), flowing to the first Instantaneous volumetric flow rate in the branch gas delivery lines of each calibration chamber (Unit: cubic meters per second), usually read by the branch main pipeline flow controller MFC.
[0030] For the collected and The data was processed using a sliding window with a preset length of 5, and a moving average filtering algorithm was used to remove high-frequency noise caused by fluid pulsation, thus preserving the true trend of fluid changes and providing a reliable data foundation for subsequent calculations.
[0031] Thus, this step establishes a physical mapping and real-time acquisition of preprocessed fluid data, providing accurate boundary conditions for subsequent model calculations and ensuring the quality of the basic data for the control system.
[0032] S2: Based on the physical dimensions of the branch gas pipeline and the average absolute pressure of the main gas distribution pipeline, determine the total physical amount of gas trapped in the branch gas pipeline.
[0033] After obtaining the real-time status of the fluid network, considering that the transmission of gas in a slender pipe is not a simple rigid body motion, but has significant compressibility, when the pipe pressure increases, the gas density increases, and the volume occupied by the same molar mass of gas decreases, resulting in a longer effective displacement time. If the time is simply estimated by dividing the pipe volume by the flow rate, the huge error caused by the pressure change will be ignored, leading to misalignment of the control timing.
[0034] Therefore, the present invention aims to construct a physical model that conforms to compressible fluid dynamics. This step aims to correct the geometric volume through real-time pressure. Since gas is a compressible fluid, the geometric volume alone cannot accurately reflect the total amount of gas molecules trapped in the pipeline. The significance of the correction is to unify the working volume under different pressures into the volume under standard conditions, so as to perform accurate flow rate and time calculations in the future.
[0035] Specifically, the following steps should be taken: Obtain the physical length and inner diameter cross-sectional area of the branch gas pipeline of the calibration chamber, and multiply the two to obtain the geometric internal volume of the branch gas pipeline; The density correction of the geometric internal volume is performed using the average absolute pressure in the common gas distribution main pipeline. Specifically, the ideal gas law can be used, with the ratio of the average absolute pressure to the standard atmospheric pressure as the correction coefficient. The geometric internal volume is then multiplied to calculate the total volume of standard gas actually contained inside the branch gas pipeline under the current pressure condition. This total volume is then determined as the total physical volume of gas retained in the branch gas pipeline.
[0036] S3: Based on the total physical amount of gas retained in the branch gas pipeline, the instantaneous volumetric flow rate in the branch gas pipeline, and the preset equivalent diffusion bias flow rate, construct a gas transmission lag model and calculate the dynamic transmission lag time required for the new gas wavefront to reach the designated calibration chamber from the gas distribution source.
[0037] The transport of gas in a slender pipe is not an incompressible rigid body motion, but is significantly affected by pressure and density. When the pipe pressure increases, the gas density increases, and the volume occupied by the same molar mass of gas decreases, resulting in a longer effective displacement time. In order to accurately describe this physical process, this invention constructs a dynamic transport lag time calculation model.
[0038] Specifically, for any calibration chamber, the total physical amount of gas retained in its branch gas supply lines is taken as the numerator; the sum of the instantaneous volumetric flow rate in the branch gas supply lines flowing to the calibration chamber and the equivalent diffusion bias flow rate is taken as the denominator; the ratio of the numerator to the denominator is calculated as the time required for the new gas wavefront to physically travel from the common gas distribution main line to the calibration chamber, and this is determined as the dynamic transmission lag time; wherein, the equivalent diffusion bias flow rate is used to characterize the natural diffusion effect of the gas and prevent the denominator from being zero.
[0039] The system periodically (every 100ms) calculates the dynamic transmission lag time for each calibration chamber, and the determination of the dynamic transmission lag time is achieved through a relational formula:
[0040] In the formula, It is the first Dynamic transmission lag time of each calibration chamber For the first The physical length of the branch gas supply lines for each calibration chamber. This refers to the cross-sectional area of the inner diameter of the gas pipeline in this branch. The average absolute pressure within the main gas distribution pipeline. For the flow to the first Instantaneous volumetric flow rate of a branch in a calibration chamber. The preset equivalent diffusion bias flow constant, is the standard atmospheric pressure constant. Wherein, It is a preset non-zero tiny positive value, set to 5 sccm, even when MFC is closed. Gas molecules inside the pipe will still move slowly through Brownian motion. This is used to characterize the natural diffusion effect at extremely low speeds and to mathematically prevent the denominator from being zero.
[0041] The formula is passed Convert the standard condition flow rate to the operating condition flow rate under current pressure, when the branch flow rate... When the denominator increases, the lag time increases. Decreasing is in accordance with physical laws; when pipeline pressure As the temperature rises, the molecular density increases, the mass of gas contained in the pipeline increases, and therefore the lag time is prolonged.
[0042] To more intuitively understand the calculation process of this formula, a specific calculation example is used for illustration: Assume that the pipeline length from a certain calibration chamber to the gas distribution center is... If the gas pipeline is a Teflon tube with an inner diameter of 4mm, then its cross-sectional area is... Square meters, average absolute pressure in the public gas distribution main pipeline (i.e., 1 standard atmosphere), flowing towards the first Instantaneous volumetric flow rate of a branch in a calibration chamber SLM (standard liters per minute) is converted to standard cubic meters per second: ; set up Extremely small and negligible. Pa.
[0043] Substitute into the formula to calculate: Molecular part: ; Denominator: ; Finally, the number was obtained Dynamic transmission lag time value of each calibration chamber This means that, under the current operating conditions, it will take approximately 15.06 seconds for the newly switched gas to flow through the 20-meter pipeline to reach the inlet of the calibration chamber.
[0044] Thus, through this lag model, the system is no longer blindly controlled, but can accurately quantify the physical delay caused by the inherent volume of the pipeline, providing a time reference for subsequent accurate compensation.
[0045] S4: In response to the concentration switching command of the automated calibration production line, calculate the concentration difference between the target set concentration and the actual concentration in the calibration chamber, and determine the basic flow adjustment amount of the calibration chamber based on the concentration difference.
[0046] After determining the arrival time of the gas, in order to solve the lag problem of traditional feedback control when switching concentrations, we cannot wait for the sensor value to change before adjusting the flow rate. At the same time, considering the huge difference in pipeline length between different calibration chambers, if an excessively large flow rate is applied to a long pipeline calibration chamber, it will cause pressure wave reflection in the pipeline, interfering with other calibration chambers.
[0047] Therefore, the present invention aims to establish an adaptive feedforward control mechanism that uses the predicted lag time to nonlinearly modulate the flow command, thereby ensuring rapid switching while preventing physical overshoot and pressure oscillation.
[0048] For any calibration chamber, when the system issues a concentration switching command, the concentration difference between the target set concentration and the actual concentration of the calibration chamber is calculated, the target set concentration specified for the calibration chamber in the concentration switching command is obtained, the current actual concentration before the concentration switching is read, and the absolute value of the difference between the two is calculated; a feedforward gain coefficient is set, and the absolute value of the difference is multiplied by the feedforward gain coefficient to obtain the initial flow rate value used to drive the rapid replacement of gas, which is determined as the basic flow rate adjustment amount.
[0049] S5: Adaptively modulate the basic flow rate adjustment using dynamic transmission lag time to generate the feedforward flow compensation for the calibration chamber.
[0050] A maximum allowable response time constant is set, and an exponential function with the natural constant as its base is constructed. The exponential part of the exponential function is composed of the negative of the ratio of the maximum response time constant to the dynamic transmission lag time. The modulation factor is calculated using the exponential function, and the modulation factor is negatively correlated with the dynamic transmission lag time. The basic flow rate adjustment is multiplied by the modulation factor to obtain the final applied flow rate correction value, which is determined as the feedforward flow rate compensation amount for the calibration chamber.
[0051] When the system issues a concentration switching command, the process of determining the feedforward flow compensation amount of the calibration chamber is achieved through the following relationship:
[0052] In this formula, For the first Feedforward flow compensation for each calibration chamber (unit: sccm). The preset feedforward gain coefficient is set to 10 sccm / ppm, based on the full-scale response characteristics of the MFC and empirical values for the pipe diameter. For the first The absolute value of the difference between the target concentration and the current actual concentration in each calibration chamber. The maximum permissible response time constant (in seconds) is set for the system, specifically 10 seconds. This time constant must be greater than the physical transmission limit of the longest pipeline in the system. For the first Dynamic transmission lag time of each calibration chamber It is a natural exponential function.
[0053] This formula implements an adaptive control strategy and effectively avoids the risks of aggressive control caused by long pipelines. It is a basic flow regulation quantity, concentration difference The larger the value, the greater the amount of gas that needs to be replaced, and therefore the higher the required compensation flow rate. The larger; It is a non-linear modulation factor used to impose lag time constraints on the fundamental terms, when the dynamic transmission lag time... When the dynamic transmission lag time is relatively small (i.e., the pipeline is short or the flow rate is high), the entire modulation factor approaches 1. At this time, the system considers the pipeline response to be fast and applies the full compensation amount to achieve ultra-fast switching; when the dynamic transmission lag time is small... When the flow rate is relatively high (i.e., the pipeline is long or the flow rate is slow), the entire modulation factor approaches 0. At this time, the system will automatically suppress the intensity of the compensation. This is to prevent the application of excessive instantaneous flow pulses in long pipelines, avoid causing violent pressure oscillations and end overshoot, and ensure the stability of long-distance transmission. This mechanism physically acts as a damper to prevent violent pressure waves caused by sudden changes in flow rate in long pipelines, thereby protecting the stability of the fluid network.
[0054] This step cleverly balances fast response and system stability through this nonlinear modulation.
[0055] To more intuitively understand the calculation process of this formula, let's illustrate it with a specific calculation example: Suppose we need to switch the gas concentration from 0 ppm to 100 ppm, then... .
[0056] Let the feedforward gain coefficient be set. If sccm / ppm, then the theoretical maximum compensation is sccm, the maximum permissible response time constant of the system. Second, The dynamic transmission lag time has been calculated. Seconds, substitute into the calculation: ; The adjustment factor is: ; Then the first Feedforward flow compensation for each calibration chamber: sccm.
[0057] It can be observed that, due to the long pipeline and a 15-second lag, the system automatically suppresses the theoretical compensation of 1000 sccm to 487 sccm. This is to prevent the application of excessive instantaneous flow pulses in long pipelines, avoiding severe pressure oscillations and end-point overshoot. If the pipeline is very short, with a lag of only 1 second, the exponential term approaches 0, the adjustment factor approaches 1, and the system will apply a full compensation of nearly 1000 sccm to achieve extremely rapid switching.
[0058] Thus, through this nonlinear compensation strategy based on lag time, the system can achieve both rapid response in short pipelines and stable transmission in long pipelines, effectively avoiding pressure coupling interference between multiple calibration chambers.
[0059] S6: The feedforward flow compensation amount is superimposed with the basic set flow to generate a flow control command to control the main pipeline flow controller and start the countdown lock mechanism to carry out the coordinated control of the automated calibration production line.
[0060] After obtaining the feedforward flow compensation for each calibration chamber, to ensure the safety of the execution process and the authenticity of the data, it is necessary to address the pressure imbalance caused by intake and the false steady-state misjudgment caused by residual old gas. If only intake is increased without adjusting exhaust, the calibration chamber will become pressurized, and if data is collected during gas transmission, incorrect readings will be obtained.
[0061] Therefore, this step aims to perform coordinated intake and exhaust actions and implement strict data acquisition time locking to achieve closed-loop control of the entire process.
[0062] Specifically, it includes: First, the feedforward flow compensation values of all calibration chambers are summed to obtain a compensation flow term. Then, the basic set flow rates of all calibration chambers are summed to obtain a basic flow term. The sum of the compensation flow term and the basic flow term is used as the final flow command. The basic set flow rate of the calibration chamber is determined by the sensor calibration process specification. The basic set flow rate refers to the constant background flow rate required to maintain the stability of the gas environment in the calibration chamber and meet the normal operation of the sensor under steady-state test conditions (for example, if the process requires the sensor to be tested at a constant flow rate of 500 sccm, then the basic set flow rate is constant at 500 sccm). This flow rate value is a preset fixed constant that does not change dynamically with the concentration switching command. It is only used as a reference base for flow control and is used to sum the feedforward flow compensation value.
[0063] The final flow control command is sent to the main pipeline flow controller (MFC), and the exhaust control signal is generated using the compensation flow term to control the opening of the exhaust valve arranged in the common gas distribution main pipeline, so that it maintains a linear following adjustment relationship with the compensation flow term; when the compensation flow term is positive, the opening of the exhaust valve is increased synchronously and linearly to maintain the relative balance of the internal pressure of the calibration chamber and avoid pressure stagnation in the calibration chamber caused by a surge in intake air volume; when the compensation flow term is zero, the opening of the exhaust valve is maintained, thereby offsetting the pressure fluctuations caused by changes in intake air volume and dynamically maintaining the internal air pressure balance.
[0064] This flow control strategy, which involves a surge followed by a decrease, physically serves a dual purpose: providing a large flow rate at the beginning of gas transmission to overcome pipeline friction and shorten transmission time, and automatically reducing the flow rate as the gas approaches the calibration chamber to prevent overpressure at the end. This fully demonstrates the significant effect of the aforementioned nonlinear compensation mechanism in resolving the contradiction between transmission lag and pressure stability in long pipelines.
[0065] Furthermore, a countdown locking mechanism is activated simultaneously with the issuance of the concentration switching command, including: Start a countdown timer and set its initial time to the dynamic transmission lag time. Monitor the remaining time of the countdown timer in real time. If the remaining time is greater than zero, it is determined that the gas transmission stage is in progress, and the data acquisition function of the sensor in the calibration chamber is disabled. When the remaining time of the countdown timer reaches zero, it is determined that the wavefront of the new gas has reached the calibration chamber, the shielding is lifted, and the data acquisition function of the sensor is restored. After the countdown timer reaches zero and the data acquisition function of the sensor is restored, the real-time reading of the sensor is immediately acquired, it is determined that the current environment has reached a steady state, and the system is allowed to formally record the calibration data of the sensor.
[0066] For example, while issuing the concentration switching command, for the first Each calibration chamber, with an immediate start-up time of [time value missing]. Before the countdown ends, the system determines that it is currently in the gas transmission period and forcibly disables the data acquisition function of the sensor in the calibration chamber, or marks the data acquired at this time as invalid / cleaning data. When the countdown reaches zero, it determines that the wavefront of the new gas has physically arrived in the calibration chamber, and the system unlocks and begins to determine whether to enter the calibration sampling based on the stability of the sensor readings.
[0067] In summary, this step, through collaborative execution and strict timing locking, completely avoids false steady-state misjudgments caused by residual old gas, ensuring that every set of entered calibration data is authentic and valid.
[0068] Combination Figure 2 The figure shows a comparison of the calibration chamber gas concentration response curves of the existing technology (conventional feedback control) and the present invention (cooperative feedforward control) during gas concentration switching. It can be seen that in the initial stage after the concentration switching command is issued, i.e., the pipeline transmission lag interval, the calibration chamber concentration does not change under either control method, reflecting the existence of physical volume time constraints. However, after the arrival of the new gas wavefront, the response curve of the existing technology rises slowly and exhibits overshoot, resulting in a longer steady-state establishment time. In contrast, the response curve using the method of the present invention rises rapidly after the calculated dynamic transmission lag time, accurately reaching the target concentration at the predetermined time without overshoot, effectively eliminating the test waiting time caused by response lag. Figure 3 This visually demonstrates the changes in the main pipeline gas distribution flow command before and after coordinated compensation. It shows that the flow command generates a feedforward compensation peak at the moment of switching, and then falls back according to an exponential law, which intuitively reflects the role of the above compensation mechanism.
[0069] In this way, through the coordinated execution of instruction synthesis and data locking, the system completely avoids false steady-state misjudgments caused by residual old gas, ensuring the authenticity and validity of each set of calibration data and improving the factory consistency of the sensor.
[0070] This invention also discloses a collaborative control system for an automated sensor calibration production line, including a processor and a memory. The memory stores computer program instructions. When the computer program instructions are executed by the processor, a collaborative control method for an automated sensor calibration production line according to the present invention is implemented. The system also includes other components well known to those skilled in the art, such as a communication bus and a communication interface. Their settings and functions are known in the art and will not be described in detail here.
[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A collaborative control method for automated sensor calibration production lines, characterized in that, include: During the operation of the sensor automated calibration production line, basic physical parameters and dynamic fluid state data of the fluid network are collected. The fluid network includes a common gas distribution main pipeline and branch gas supply pipelines connecting the common gas distribution main pipeline and the calibration chamber. The basic physical parameters include the physical dimension information of the branch gas supply pipelines, and the dynamic fluid state data includes the average absolute pressure in the common gas distribution main pipeline and the instantaneous volumetric flow rate in the branch gas supply pipelines. Based on the physical dimensions of the branch gas pipeline and the average absolute pressure, the total physical amount of gas retained in the branch gas pipeline is determined. Combined with the instantaneous volumetric flow rate and the preset equivalent diffusion bias flow rate, a gas transmission lag model is constructed. The gas transmission lag model is then used to calculate the dynamic transmission lag time of the new gas wavefront reaching the calibration chamber. In response to the concentration switching command of the automated calibration production line, the concentration difference between the target set concentration and the actual concentration in the calibration chamber is calculated, and the basic flow rate adjustment is determined based on the concentration difference. The basic flow rate adjustment is adaptively modulated using the dynamic transmission lag time to generate a feedforward flow compensation amount for the calibration chamber. The feedforward flow compensation amount is then superimposed with the basic set flow rate to generate a flow control command to control the main pipeline flow controller, thereby achieving coordinated control of the calibration production line.
2. The collaborative control method according to claim 1, characterized in that, Based on the physical dimensions of the branch gas pipeline and the average absolute pressure, the total physical amount of gas retained in the branch gas pipeline is determined, including: Obtain the physical length and inner diameter cross-sectional area of the branch gas pipeline, and multiply the two to obtain the geometric internal volume of the branch gas pipeline; The average absolute pressure is used to correct the density of the geometric internal volume, and the total volume of standard gas actually contained inside the branch gas pipeline under the current pressure condition is calculated. This total volume is determined as the total physical volume of gas retained in the branch gas pipeline.
3. The collaborative control method according to claim 1, characterized in that, A gas transport lag model is constructed, and the dynamic transport lag time of a new gas wavefront reaching the calibration chamber is calculated using the gas transport lag model. This includes: taking the total physical amount of gas retained in the branch gas supply pipeline as the numerator; taking the sum of the instantaneous volumetric flow rate in the branch gas supply pipeline flowing to the calibration chamber and the equivalent diffusion bias flow rate as the denominator; calculating the ratio of the numerator to the denominator to obtain the time required for the new gas wavefront to physically transport from the common gas distribution pipeline to the calibration chamber, and determining this as the dynamic transport lag time; wherein, the equivalent diffusion bias flow rate is used to characterize the natural diffusion effect of the gas and prevent the denominator from being zero.
4. The collaborative control method according to claim 1, characterized in that, Calculating the concentration difference between the target set concentration and the actual concentration in the calibration chamber, and determining the basic flow rate adjustment based on the concentration difference, includes: obtaining the target set concentration specified for the calibration chamber in the concentration switching command, reading the current actual concentration before the concentration switching, and calculating the absolute value of the difference between the two; setting a feedforward gain coefficient, multiplying the absolute value of the difference by the feedforward gain coefficient to obtain the initial flow rate value used to drive rapid gas replacement, and determining it as the basic flow rate adjustment.
5. The collaborative control method according to claim 1, characterized in that, Adaptively modulating the basic flow rate adjustment using the dynamic transmission lag time to generate a feedforward flow rate compensation for the calibration chamber includes: setting a maximum allowable response time constant for the system; constructing an exponential function with a natural constant as the base, the exponent of which is the negative of the ratio of the maximum response time constant to the dynamic transmission lag time; calculating a modulation factor using the exponential function, the modulation factor being negatively correlated with the dynamic transmission lag time; and multiplying the basic flow rate adjustment by the modulation factor to obtain the final applied flow rate correction value, which is determined as the feedforward flow rate compensation for the calibration chamber.
6. The cooperative control method according to claim 1, characterized in that, The process of generating a flow control command to control the main pipeline flow controller includes: superimposing the feedforward flow compensation values of all calibration chambers to obtain a compensation flow term; superimposing the basic set flow values of all calibration chambers to obtain a basic flow term; and using the sum of the compensation flow term and the basic flow term as the final flow command. The final flow control command is then sent to the main pipeline flow controller. Simultaneously, an exhaust control signal is generated using the compensation flow term to control the opening of the exhaust valve located in the common gas distribution main pipeline, ensuring a linear following adjustment relationship with the compensation flow term. When the compensation flow term is positive, the opening of the exhaust valve is synchronously and linearly increased; when the compensation flow term is zero, the opening of the exhaust valve is maintained.
7. The cooperative control method according to claim 1, characterized in that, While generating flow control commands to control the main pipeline flow controller, a countdown lock mechanism is also initiated, including: Simultaneously with issuing the concentration switching command, a countdown timer is started, and the initial time of the countdown timer is set to the dynamic transmission lag time. The remaining time of the countdown timer is monitored in real time. If the remaining time is greater than zero, it is determined that the gas transmission stage is in progress, and the data acquisition function of the sensor in the calibration chamber is disabled. When the remaining time of the countdown timer returns to zero, it is determined that the wavefront of the new gas has arrived in the calibration chamber, the shielding is lifted, and the data acquisition function of the sensor is restored.
8. The cooperative control method according to claim 7, characterized in that, After the sensor's data acquisition function is restored, perform the following operations: immediately acquire the sensor's real-time readings, and allow the system to formally input the calibration data acquired by the sensor.
9. The cooperative control method according to claim 1, characterized in that, Before collecting the basic physical parameters and dynamic fluid state data of the fluid network, the following steps are also included: A physical mapping relationship of the fluid network is established in the configuration database of the control system, and the geometric and physical parameters of each calibration chamber of the automated calibration production line are stored in advance. The geometric and physical parameters include: the physical length of the branch gas supply pipeline, the inner diameter cross-sectional area of the branch gas supply pipeline, and the effective volume of the calibration chamber itself. The real-time average absolute pressure of the common gas distribution main pipeline is collected by sensors arranged on the common gas distribution main pipeline. The instantaneous volumetric flow rate of the branch gas supply pipeline flowing to each calibration chamber is collected by sensors arranged on each of the branch gas supply pipelines.
10. A collaborative control system for an automated sensor calibration production line, characterized in that, The cooperative control system includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the cooperative control method as described in any one of claims 1-9.