A multi-working-condition self-tracing calibration method and system for a pneumoperitoneum machine

Abstract

The application discloses a multi-working-condition self-tracing calibration method and system for a pneumoperitoneum machine, and relates to the technical field of pneumoperitoneum machine metering. The method comprises the following steps: a standard circuit is constructed to apply back pressure and inject a controllable leakage amount; in one uninterrupted calibration, the calibrated pneumoperitoneum machine is controlled to enter stable pressure, stable flow and leakage disturbance working conditions in sequence, and data is synchronously collected through a traceable pressure reference and a flow reference working in cooperation; reference measurement values are compared with the indication values of the calibrated pneumoperitoneum machine, and pressure coupling errors, flow coupling errors and dynamic response characteristics are calculated; standard state conversion is carried out based on preset standard pressure and standard temperature, calibration coefficients are generated through fitting, and measurement values are corrected, a judgment result is generated by comparing the coupling errors and the dynamic response characteristics with preset threshold values; and an automatic report containing working condition types, residuals, final calibration measurement results and uncertainties is generated. Through three-working-condition linkage calibration and environmental factor compensation, the calibration accuracy and traceability are improved.

Description

Technical Field

[0001] This invention relates to the field of metrological calibration of insufflators, and more specifically, to a multi-condition self-traceable calibration method and system for insufflators. Background Technology

[0002] Medical insufflators are crucial equipment in laparoscopic surgery. They establish and maintain a pneumoperitoneum environment by introducing gases such as carbon dioxide into the abdominal cavity, providing surgeons with operating space and a field of vision. Precise control of insufflator pressure and gas flow rate is essential, and the accuracy of these measurements directly impacts surgical safety.

[0003] The existing insufflation machine calibration technology has the following shortcomings:

[0004] 1. Incomplete coverage of operating conditions, making it difficult to reflect real-world usage scenarios:

[0005] Existing calibration techniques typically calibrate pressure, flow rate, and leakage separately, or only under a single operating condition, which makes it difficult to cover the coupling characteristics of insufflators under three operating conditions: stable pressure, stable flow, and leakage disturbances. In actual clinical use, insufflators need to switch between different operating conditions, and separate or single-condition calibration cannot reflect the dynamic response characteristics and parameter coupling effects during the switching process.

[0006] 2. Insufficient compensation for environmental factors makes it difficult to eliminate systemic biases:

[0007] The measurement performance of insufflators is significantly affected by ambient temperature, gas source pressure, and the type of gas used (such as carbon dioxide, helium, etc.). Existing calibration methods under single environmental conditions cannot effectively eliminate systematic biases caused by the coupling of multiple factors, and the repeatability and cross-condition consistency of calibration results are insufficient.

[0008] 3. The traceability of calibration results is weak:

[0009] In the existing technology, the traceability of calibration benchmarks and the completeness of calibration reports and audit records need to be strengthened, making it difficult to effectively verify and audit calibration results.

[0010] 4. Lack of dynamic performance evaluation:

[0011] Existing technologies focus on evaluating steady-state indicators, but lack systematic quantitative assessment methods for dynamic response characteristics (such as pressure rise time and settling time) during operating condition switching. Summary of the Invention

[0012] The purpose of this invention is to provide a multi-condition self-traceable calibration method and system for insufflators, in order to solve the following problems existing in the prior art: the calibration condition is singular and cannot fully cover the multi-condition scenarios of pressure stabilization, flow stabilization and leakage disturbances in actual use of insufflators; the influence of environmental factors (temperature, gas source pressure, gas type) on the calibration results is not effectively compensated, and system deviations are difficult to eliminate; the traceability of calibration results is not strong, and there is a lack of complete automatic reports and audit records; there is a lack of quantitative evaluation of the dynamic response characteristics when switching operating conditions.

[0013] To achieve the above-mentioned objectives, this invention provides a multi-condition self-traceable calibration method for insufflators, comprising the following steps:

[0014] S1: Construct the standard circuit, which is used to apply back pressure to the pneumoperitoneum machine under calibration and inject a controllable leakage amount;

[0015] S2: During a continuous calibration process, the pneumoperitoneum machine under calibration is controlled to sequentially enter and maintain preset pressure stabilization, flow stabilization, and leakage disturbance conditions. Through the traceable pressure reference and flow reference in the standard circuit working in concert, the measured values ​​of the pressure reference, the flow reference, and the pneumoperitoneum machine under calibration are continuously and synchronously collected throughout the entire calibration process.

[0016] S3: Compare the measured values ​​of the pressure reference and the flow reference collected at the same time with the pressure value and flow value in the measured values ​​of the pneumoperitoneum machine being calibrated, respectively, to obtain calibration data;

[0017] S4: Calculate pressure coupling error and flow coupling error based on calibration data; calculate dynamic response characteristics based on transient data during operating condition switching using a dynamic response model;

[0018] S5: Based on the measured ambient temperature, gas source pressure, and gas type data, the measured values ​​of the pressure reference and the flow reference are adjusted according to a preset standard pressure. and preset standard temperature The standard state is converted to obtain the pressure reference value and flow reference value under the standard state; the pressure reference value and flow reference value are fitted with the corresponding values ​​in the measured values ​​of the pneumoperitoneum machine under calibration to generate calibration coefficients; the measured values ​​of the pneumoperitoneum machine under calibration are corrected using the calibration coefficients to obtain the final calibration measurement result; the pressure coupling error, the flow coupling error and the dynamic response characteristic are compared with their respective preset criterion thresholds to generate a judgment result on whether the performance of the pneumoperitoneum machine under calibration is qualified;

[0019] S6: Generate an automatic report and audit record. The report includes the operating condition type, residual, final calibration measurement result, and calibration result uncertainty covered in step S2. The residual is obtained through the pressure coupling error and the flow coupling error. The calibration result uncertainty is obtained by combining the measurement uncertainty of the pressure reference and the flow reference, the uncertainty introduced by environmental factors, and the fitting uncertainty of the calibration coefficient.

[0020] The applicant's research revealed that existing insufflation machine calibration technologies calibrate pressure, flow rate, and leakage separately or under single operating conditions. This results in a failure to cover systemic biases caused by the coupling of these three factors and environmental changes, leading to insufficient repeatability and traceability of calibration results. This invention constructs a calibration system with a standard loop. During a continuous calibration process, it sequentially executes three operating conditions while simultaneously acquiring baseline measurements and the readings of the insufflation machine being calibrated. Based on the compared calibration data, it calculates pressure coupling errors and flow rate coupling errors, and calculates dynamic response characteristics using a dynamic response model. It introduces environmental factors for standard state conversion, fits and generates calibration coefficients to correct measured values, and compares the coupling errors and dynamic response characteristics with preset criterion thresholds to generate a judgment result. Finally, it generates an automatic report containing the operating condition type, residuals, final calibration measurement results, and combined uncertainty. This method provides a complete multi-operating condition self-traceable calibration process that comprehensively covers three operating conditions: stable pressure, stable flow, and leakage disturbances. It eliminates the influence of environmental factors on calibration results; it generates calibration coefficients to correct measured values ​​and obtain final calibration measurement results; it generates performance compliance judgment results; and it generates complete automatic reports and audit records.

[0021] Preferably, the flow coupling error is calculated by establishing a steady-state coupling model using the law of conservation of mass, specifically including:

[0022] The steady-state coupling model is as follows:

[0023] ;

[0024] in, For traffic, For pressure, For leakage amount, The equivalent conductance of the system as determined by experiments;

[0025] For the preset standard pressure and the set leakage amount Substituting into the steady-state coupling model, the predicted flow rate used to maintain this state is calculated. ;

[0026] The measured value of the flow reference With the predicted flow Compare and calculate the relative deviation :

[0027] ;

[0028] Based on the relative deviation Obtain the flow coupling error.

[0029] This method establishes a steady-state coupling model based on the law of mass conservation, using the system's equivalent conductance (F) to reflect system characteristics through experimental calibration. Preset standard pressures and leakage rates are substituted into the model to calculate the predicted flow rate. The measured flow rate is compared with the predicted flow rate to calculate the relative deviation, which is defined as the flow coupling error. By establishing a clear steady-state coupling mathematical model, this method provides specific calculation methods and formulas for the flow coupling error, making the error analysis operable and reproducible, and providing a quantitative basis for subsequent judgment and precise calibration.

[0030] Preferably, the dynamic response characteristics are calculated using a dynamic response model, including:

[0031] Based on the law of conservation of mass, a dynamic response model describing the rate of change of pressure over time is established. The formula for the dynamic response model is as follows:

[0032] ;

[0033] in, These are constants related to container volume, gas temperature, and gas type. For traffic, For pressure, Let t be the leakage amount and t be the time.

[0034] During the transient process of switching operating conditions, based on the measurement data synchronously collected from the pressure reference and flow reference, the dynamic performance index, which includes at least the pressure or flow rise time and the adjustment time, is calculated and output using the dynamic response model. The dynamic performance index is used as a quantitative representation of the dynamic response characteristics.

[0035] This method provides a specific calculation model and method for dynamic response characteristics, which can output dynamic performance indicators such as pressure or flow rise time and settling time, and clearly define these indicators as quantitative representations of dynamic response characteristics, thereby realizing an objective evaluation of the dynamic performance of the pneumoperitoneum machine.

[0036] Preferably, step S5 specifically includes:

[0037] S5.1: Based on the gas law and gas molar mass or density parameters, the measured values ​​of the pressure reference and the flow reference, combined with the measured ambient temperature, gas source pressure, and gas type, are converted to the preset standard pressure. and preset standard temperature Status, obtain pressure and flow reference values ​​under standard conditions;

[0038] S5.2: The pressure reference value and flow reference value under the standard state are respectively fitted with the corresponding values ​​in the measured values ​​of the insufflator under calibration to generate pressure calibration coefficient and flow calibration coefficient for correcting the measured values ​​of the insufflator.

[0039] S5.3: Using the pressure calibration coefficient and the flow calibration coefficient, the pressure measurement value and flow measurement value of the insufflator under the corresponding operating conditions are corrected respectively to obtain the final calibration measurement result;

[0040] S5.4: Compare the pressure coupling error, flow coupling error, and dynamic performance index with their respective preset criterion thresholds to generate a judgment result on whether the performance of the pneumoperitoneum machine is qualified.

[0041] Preferably, step S5 further includes:

[0042] Change the set leakage amount Repeat steps S2 to S5 until the preset leakage range is covered, obtain the flow coupling error under different leakage rates, and establish the set leakage rate. The relationship curve between the flow rate coupling error and the actual flow rate is used to accurately calibrate the insufflator being calibrated.

[0043] This method limits the number of iterations by setting cyclic boundary conditions (covering the preset leakage range) and establishes a relationship curve between leakage and flow coupling error. This allows for the quantification of the impact of leakage on the accuracy of system flow control and provides guidance for precise calibration based on this relationship curve.

[0044] Preferably, the conversion method in step S5.1 specifically includes:

[0045] When the gas type is a special gas, the van der Waals equation is used to describe the relationship between the gas's pressure, volume, and temperature. The van der Waals equation is as follows:

[0046] ;

[0047] in, These are constants related to the properties of the gas. For pressure, Let n be the volume, n be the amount of substance, R be the gas constant, and T be the thermodynamic temperature.

[0048] For pressure conversion, the compressibility factor of the special gas under standard conditions is used. Compressibility factor under measured conditions The converted pressure reference value was calculated. The calculation method is as follows:

[0049] ;

[0050] in, For actual measured temperature, The measured value of the pressure reference.

[0051] The applicant's research found that when the insufflator is filled with special gases (such as helium or mixed gases), simply using the ideal gas law for standard state conversion produces significant errors. This method provides a more accurate pressure conversion method for special gases, expanding the applicability of the calibration method to different gas types and ensuring calibration accuracy in special gas scenarios.

[0052] Preferably, the generation of automatic reports and audit records in step S6 further includes:

[0053] The calibration results include the final calibration measurement results and the judgment results;

[0054] The calibration results obtained under different working conditions are compared and analyzed to evaluate the performance stability of the calibrated pneumoperitoneum machine under different working conditions, and the comparison and analysis results are incorporated into the automatic report and audit record.

[0055] The calibration results of this method include the final calibration measurement results and judgment results; comparative analysis of calibration results obtained under different operating conditions; evaluation of the performance stability of the insufflator under different operating conditions; and incorporation of the comparative analysis results into the automatic report and audit records. This enables the automatic report to compare and analyze calibration results under different operating conditions, and thereby evaluate the performance stability of the insufflator, enhancing the analytical depth and practical value of the report, and facilitating the timely detection of performance differences of the insufflator under different operating conditions.

[0056] Preferably, in step S1, the applied back pressure and the injected leakage amount are controlled by adjusting the opening degree of the valves on the pipeline in the standard circuit. By adjusting the opening degree of the valves on the pipeline constituting the standard circuit, the applied back pressure and the injected leakage amount are precisely controlled.

[0057] Preferably, in step S2, the control system sequentially switches and maintains the voltage stabilization condition, the current stabilization condition, and the leakage disturbance condition according to a preset sequence and time interval.

[0058] This invention also provides a multi-condition self-traceable calibration system for insufflators, the system being based on the aforementioned multi-condition self-traceable calibration method for insufflators, the system comprising:

[0059] The standard loop construction module includes pipes, valves, and a back pressure loading device, which is used to construct a standard loop. By controlling the opening of the valves, it can apply back pressure to the pneumoperitoneum machine under calibration and inject a controllable amount of leakage.

[0060] The working condition switching module includes a control system and an actuator, which is used to control the pneumoperitoneum machine being calibrated to enter and maintain preset pressure stabilization working condition, flow stabilization working condition and leakage disturbance working condition in a preset order and time interval during a continuous calibration process.

[0061] The reference reading module includes traceable pressure and flow references, as well as a data acquisition and processing unit, for synchronously acquiring and comparing the measured values ​​of the pressure reference, the measured values ​​of the flow reference, and the readings of the pneumoperitoneum machine being calibrated.

[0062] The calculation module is used to calculate pressure coupling error, flow coupling error, and dynamic response characteristics based on synchronously acquired data;

[0063] The compensation module is used to input measured ambient temperature, gas source pressure and gas type data for standard state conversion, and generate calibration coefficients and performance qualification results;

[0064] The report generation module is used to generate automatic reports and audit logs that include the covered operating conditions, residuals, final calibration measurement results, and calibration result uncertainties.

[0065] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0066] By using three-condition linkage calibration and combining standard state conversion compensation with various environmental factors such as temperature, gas source pressure, and gas type, the performance of the pneumoperitoneum machine in actual use can be more accurately reflected, effectively reducing system deviation and improving the accuracy of calibration results.

[0067] This method can comprehensively cover various working conditions of the pneumoperitoneum machine, such as pressure stabilization, flow stabilization, and leakage disturbances, reducing the differences in calibration results caused by changes in working conditions and improving the repeatability and consistency of calibration across working conditions.

[0068] This method uses traceable pressure and flow references for synchronous acquisition and comparison, and generates an automatic report and audit record that includes coverage conditions, coupling error as residual, final calibration measurement results, and calibration result uncertainty synthesized from various uncertainty components. This achieves traceable management of the calibration process and facilitates the verification and auditing of calibration results.

[0069] This method, by establishing a dynamic response model and calculating dynamic performance indicators such as pressure or flow rise time and settling time, can quantitatively evaluate the dynamic response characteristics of the pneumoperitoneum machine during the switching of operating conditions, thus making up for the shortcomings of existing technologies that only focus on steady-state indicators.

[0070] This method establishes a leakage-flow coupling error relationship curve by changing the set leakage amount and repeating the experiment. It can quantify the impact of leakage on the accuracy of system flow control and provide a more reliable guarantee for laparoscopic surgery. Attached Figure Description

[0071] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.

[0072] Figure 1 This is a flowchart illustrating a multi-condition self-traceable calibration method for insufflators.

[0073] Figure 2 This is a schematic diagram of the standard loop pipeline in a multi-condition self-traceability calibration method for pneumoperitoneum machines. Detailed Implementation

[0074] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0075] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0076] Example 1;

[0077] Please refer to Figure 1 , Figure 1 This invention provides a multi-condition self-traceable calibration method for insufflators, comprising the following steps:

[0078] S1 standard circuit construction steps include: constructing the standard circuit, which is used to apply back pressure to the insufflator under calibration and inject a controllable leakage amount;

[0079] The S2 multi-condition synchronous data acquisition step includes: during a continuous calibration process, controlling the insufflator under calibration to sequentially enter and maintain preset pressure stabilization, flow stabilization, and leakage disturbance conditions. Through the traceable pressure and flow references in the cooperating standard loop, the measured values ​​of the pressure reference, the flow reference, and the insufflator under calibration are continuously and synchronously acquired throughout the entire calibration process. In this method, during a continuous calibration process, the control system sequentially controls the insufflator under calibration to enter and maintain pressure stabilization, flow stabilization, and leakage disturbance conditions according to a preset order and time interval. Throughout the entire process and time period, data is continuously and synchronously acquired through the cooperating traceable pressure and flow references. Seamless switching between the three conditions within the same sequence allows the calibration results to reflect the comprehensive performance of the insufflator under different operating states.

[0080] The S3 benchmark comparison step includes: comparing the measured values ​​of the pressure benchmark and the measured values ​​of the flow benchmark collected at the same time with the pressure value and flow value in the measured values ​​of the pneumoperitoneum machine being calibrated, respectively, to obtain calibration data;

[0081] The S4 coupling error and dynamic response calculation steps include: calculating pressure coupling error and flow coupling error based on calibration data; and calculating dynamic response characteristics based on transient data during operating condition switching using a dynamic response model.

[0082] The S5 standard state conversion and performance assessment steps include: based on measured ambient temperature, gas source pressure, and gas type data, adjusting the measured values ​​of the pressure reference and flow reference based on a preset standard pressure. and preset standard temperature The standard state conversion yields pressure and flow reference values ​​under standard conditions. These reference values ​​are then fitted with corresponding values ​​from the measurements of the insufflator under calibration to generate calibration coefficients. These coefficients are used to correct the measurements of the insufflator, resulting in the final calibration measurement result. The pressure coupling error, flow coupling error, and dynamic response characteristics are compared with their respective preset threshold values ​​to generate a judgment result regarding the performance of the insufflator under calibration. This method incorporates measured ambient temperature, gas source pressure, and gas type data to perform standard state conversion on the pressure and flow reference values, obtaining reference values ​​under standard conditions. These reference values ​​are then fitted with the readings of the insufflator under calibration to generate calibration coefficients, which are used to correct the measurements. Simultaneously, a performance qualification judgment result is generated based on the comparison results of coupling error and dynamic response characteristics with preset threshold values. For special gases (such as helium), the van der Waals equation is used to describe the gas characteristics, and a compressibility factor is introduced for accurate pressure conversion.

[0083] S6: Automatic report generation step, including: generating an automatic report and audit record, wherein the report includes the operating condition type, residual, final calibration measurement result and calibration result uncertainty covered in step S2; wherein the residual is obtained through the pressure coupling error and the flow coupling error, and the calibration result uncertainty is obtained by synthesizing the measurement uncertainty of the pressure reference and the flow reference, the uncertainty introduced by environmental factors and the fitting uncertainty of the calibration coefficient.

[0084] This method establishes a dynamic response model describing the rate of change of pressure over time based on the law of conservation of mass. During the transient process of switching operating conditions, it uses synchronously acquired measurement data to calculate and output dynamic performance indicators such as the rise time and settling time of pressure or flow, and uses these dynamic performance indicators as a quantitative representation of dynamic response characteristics.

[0085] This invention establishes a calibration strategy that sequentially executes three operating conditions—pressure stabilization, flow stabilization, and leakage disturbance—during a single, uninterrupted calibration process. By synchronously acquiring and coupling the pressure and flow data under these three conditions, the true performance of the insufflator can be reflected across all operating scenarios, achieving comprehensive calibration coverage.

[0086] This invention, based on the law of conservation of mass, establishes a steady-state coupling model and a dynamic response model for the pressure-flow-leakage relationship. The coupling error is calculated by comparing model predictions with measured values; the dynamic response characteristics are quantified through transient data analysis. This achieves a precise description of the nonlinear coupling relationship between parameters.

[0087] This invention, based on the gas law and gas physical property parameters, uniformly converts measured flow and pressure values, along with ambient temperature, gas source pressure, and gas type, to preset standard temperature and pressure conditions. This method eliminates the influence of environmental factors on measurement results, making calibration results under different conditions comparable.

[0088] This invention generates calibration coefficients to correct measured values ​​by fitting a function between a reference value under standard conditions and the reading of the insufflator under test; at the same time, it compares the coupling error and dynamic performance indicators with preset criterion thresholds to generate a judgment result on whether the performance of the insufflator is qualified.

[0089] In this embodiment of the invention, the standard circuit refers to the test pipeline circuit used in the calibration method of the present invention to simulate the abdominal cavity environment and apply back pressure and inject a controllable leakage into the pneumoperitoneum machine under calibration. The standard circuit mainly includes pipes, valves, and a back pressure loading device. The pipes connect the pneumoperitoneum machine under calibration, the back pressure loading device, the leakage injection device, and the pressure and flow references, forming a complete gas flow path. The valves are installed on the pipes, and their opening degree is precisely controlled to achieve precise adjustment of the back pressure and leakage amount. The back pressure loading device applies a preset back pressure to the output end of the pneumoperitoneum machine under calibration to simulate the gas pressure inside the abdominal cavity. Please refer to [reference needed]. Figure 2 The pneumoperitoneum machine is connected to the traceable flow reference via the first pipe. The traceable flow reference is connected to the back pressure loading device via the second pipe. The traceable pressure reference is connected to the second pipe via the third pipe. A back pressure regulating valve is installed near the back pressure loading device on the second pipe. The back pressure loading device is connected to the simulated abdominal cavity via the fourth pipe. The controllable leakage injection device is connected to the simulated abdominal cavity via the fifth pipe. A leakage regulating valve is installed on the fifth pipe. The simulated abdominal cavity is connected to the vent via the corresponding pipe.

[0090] The standard circuit has the following two functions: (1) Applying back pressure to the insufflator under calibration: By adjusting the opening of the valve on the pipeline, the back pressure applied by the back pressure loading device can be precisely controlled to simulate the working environment of different pressure levels in the abdominal cavity during laparoscopic surgery. (2) Injecting a controllable leakage amount into the insufflator under calibration: By adjusting the opening of the valve on the pipeline, the leakage amount injected can be precisely controlled to simulate various gas leakage scenarios that may occur during surgery (such as leakage around the trocar, leakage caused by the entry and exit of instruments, etc.).

[0091] The purpose of the standard loop is to provide a controllable and reproducible simulated abdominal cavity test environment for the calibration process, so that the pneumoperitoneum machine under calibration experiences three operating conditions in sequence: pressure stabilization, flow stabilization, and leakage disturbance under different back pressure conditions and different leakage amounts, thereby comprehensively evaluating its performance in actual use.

[0092] The pressure stabilization mode refers to a working state in which the pneumoperitoneum machine is controlled to enter and maintain during a continuous calibration process. In this state, the pneumoperitoneum machine aims to maintain a preset constant target pressure value. By automatically adjusting the output flow rate, the actual pressure in the simulated abdominal cavity container is stabilized near the preset target pressure value. The specific difference range between the actual pressure value and the preset target pressure value can be adjusted according to actual needs. This embodiment of the invention does not impose any corresponding limitations.

[0093] Among them, the steady flow condition refers to a working state in which the calibrated pneumoperitoneum machine is controlled to enter and maintain during a non-stop calibration process. In this state, the calibrated pneumoperitoneum machine continuously outputs a preset flow rate of gas to the simulated abdominal cavity container with the control objective of maintaining a preset constant target flow rate. At this time, the pressure inside the simulated abdominal cavity container gradually changes as gas is filled in.

[0094] Among them, the leakage disturbance condition refers to a working state that the calibrated pneumoperitoneum machine is controlled to enter and maintain during a non-stop calibration process. In this state, the standard circuit actively introduces a preset leakage amount through a controllable leakage injection device to simulate various gas leakage scenarios that may occur in actual surgery (such as poor sealing around the trocar, intermittent leakage caused by frequent entry and exit of surgical instruments, etc.). The calibrated pneumoperitoneum machine compensates for the leakage by automatically adjusting the output flow rate to maintain stable abdominal pressure.

[0095] Among them, the traceable pressure reference and flow reference in the standard circuit working in concert refer to the fact that the traceable pressure reference and flow reference are physically connected to the main circuit of the standard circuit independently and without interference, and the two are completely synchronized in data acquisition timing, so as to be able to measure the same physical state (the gas state at the same time and the same cross section) at the same time.

[0096] The pressure reference is connected in parallel to the main pipeline via a pressure measurement branch, measuring the instantaneous pressure of the gas in the main pipeline. The flow reference is connected in series to the main pipeline, measuring the volumetric flow rate of the gas flowing through the main pipeline. Although the two are connected in different ways (one in parallel, one in series), they are arranged at the same measurement cross-section to ensure that the gas state is measured at the same time and the same physical location.

[0097] The pressure reference measurement value and the flow reference measurement value are synchronously acquired by the data acquisition and processing unit under the same clock signal. The pressure reference measurement value, flow reference measurement value, and the pressure and flow readings of the calibrated pneumoperitoneum machine acquired at the same time constitute a complete set of calibration data, which is used for subsequent comparison and coupling error analysis.

[0098] Collaborative operation can eliminate measurement errors introduced by time asynchrony, ensuring that the calculated pressure coupling error and flow coupling error truly reflect the performance deviation of the pneumoperitoneum machine being calibrated, rather than artifacts caused by measurement timing. It provides a precise reference benchmark at the same moment for coupling error analysis.

[0099] The traceable pressure reference is connected in parallel to the main pipeline via a pressure measurement branch, specifically after the gas output port of the insufflator being calibrated and before the inlet of the simulated abdominal cavity container. One end of the pressure measurement branch is connected to the main pipeline, and the other end is connected to the pressure sensor.

[0100] The traceable flow reference is connected in series on the main pipeline, specifically after the gas output port of the insufflator being calibrated and before the inlet of the simulated abdominal cavity container, and its connection point with the pressure reference is located at the same measurement section or adjacent to the main pipeline.

[0101] The connection points of the pressure reference and the flow reference on the main pipeline should be as close as possible (the specific range can be adjusted according to actual needs, and this embodiment of the invention does not impose any corresponding limitations) to ensure that both measure the gas state at the same physical location. Preferably, the parallel connection point of the pressure reference is located immediately downstream of the flow reference, or both share the same measurement cross-section.

[0102] The flow rate reference is connected in series in the main pipeline, and the gas flows through the flow rate reference to reach the simulated abdominal cavity container; the pressure reference is connected in parallel in the main pipeline, and the gas pressure in the main pipeline is sensed through the pressure measuring branch pipe; both are connected to the same measuring section or adjacent position in the main pipeline; the data acquisition unit synchronously acquires the measurement data of the pressure reference and the flow rate reference under the same clock signal, as well as the pressure and flow rate readings displayed by the pneumoperitoneum machine itself at the same time.

[0103] Specifically, the measured values ​​of the pressure reference and the flow reference, collected at the same time, are compared with the pressure and flow values ​​in the measured values ​​of the pneumoperitoneum machine being calibrated to obtain calibration data. The specific implementation method is as follows:

[0104] At the same time, four types of data were collected simultaneously:

[0105] The measured value P of the pressure reference measure Flow rate reference measurement value Q measure The pressure reading P of the pneumoperitoneum machine being calibrated display and the flow rate reading Q of the insufflator display The comparison is performed by comparing P at the same time. measure With P display Subtracting the two values ​​yields the pressure deviation (pressure error); the pressure at the same moment is then compared with the pressure at the same time. measure With Q display Subtracting the values ​​yields the flow deviation (flow error). These deviation values ​​are the calibration data.

[0106] The pressure coupling error can be calculated by directly comparing the pressure reference measurement value collected at the same time with the pressure reading of the pneumoperitoneum machine being calibrated. For example, the pressure reading P of the pneumoperitoneum machine being calibrated collected at the same time can be used as the reference measurement value. display The measured value P relative to the pressure reference measure By comparing and calculating the pressure deviation, the pressure coupling error is obtained.

[0107] The transient data during the switching of operating conditions refers to the time-series data that is synchronously collected from the pressure and flow references during the switching time and the subsequent transition process, reflecting the dynamic changes of the system from one steady state to another. Since step S2 collects data continuously throughout the entire time period, when the control system switches operating conditions in a preset sequence (e.g., from a stable pressure condition to a stable flow condition, or from a stable flow condition to a leakage disturbance condition), the transient data during the switching time and the period before the system returns to stability after the switching is still being recorded.

[0108] Specifically, the pressure reference value and flow rate reference value are fitted with the corresponding values ​​in the measured values ​​of the pneumoperitoneum machine being calibrated to generate calibration coefficients. The specific implementation method is as follows:

[0109] The fitting operation involves two sets of data: the pressure reference value and flow reference value under standard conditions and the corresponding readings of the insufflator under calibration. The fitting method can be the least squares method or other applicable function fitting methods. The specific steps of the fitting method will not be described in detail in this embodiment. Fitting relationships are established for the pressure data and flow data respectively, and pressure calibration coefficients and flow calibration coefficients are generated respectively.

[0110] Specifically, the pressure calibration coefficient and the flow calibration coefficient are used to correct the pressure measurement value and flow measurement value of the insufflator under corresponding operating conditions. The specific implementation method is as follows:

[0111] The correction of the measured value refers to using the calibration coefficients generated by function fitting in step S5.2 to correct the original measured value (pressure reading P) displayed by the insufflator under calibration during actual use. display and flow rate indication Q display Mathematical transformations are performed to eliminate systematic biases and obtain a final calibration measurement result that is closer to the true value (i.e., closer to the traceable reference measurement value).

[0112] Pressure correction includes:

[0113] When the pressure calibration coefficient generated in step S5.2 is a gain term and offset terms At that time, the pressure reading P of the insufflator under any operating condition was measured. display The following corrections are made:

[0114] ;

[0115] Among them, P corrected This is the corrected pressure value, which serves as the pressure component in the final calibration measurement result.

[0116] The traffic correction includes:

[0117] When the flow calibration coefficient generated in step S5.2 is a gain term and offset terms At that time, the flow rate Q of the insufflator under any operating condition is measured. display The following corrections are made:

[0118] ;

[0119] Among them, Q corrected This is the corrected flow rate value, which serves as the flow rate component in the final calibration measurement result.

[0120] If the offset term of the pneumoperitoneum machine being calibrated is found to be approximately zero or less than a preset threshold through function fitting, it can be considered as zero.

[0121] The above correction operation maps the measured values ​​displayed by the insufflator itself to a standard state measurement space referenced by a traceable benchmark, using a functional relationship characterized by calibration coefficients. The corrected final calibration measurement results eliminate systematic deviations caused by environmental factors (temperature, gas source pressure, gas type) and compensate for inherent errors in the insufflator's measurement channels, thus accurately reflecting the gas output performance of the insufflator in actual use.

[0122] Specifically, the pressure coupling error, the flow coupling error, and the dynamic response characteristic are compared with their respective preset criterion thresholds. The specific implementation method is as follows:

[0123] The pressure coupling error, flow coupling error, and various dynamic performance indicators calculated in step S4 are compared one by one with their respective preset threshold values. The pneumoperitoneum machine under calibration is deemed to be qualified only when all indicators meet their corresponding threshold requirements; if any indicator exceeds its corresponding threshold, it is deemed unqualified.

[0124] Comparison of pressure coupling errors: The pressure coupling error (P) calculated in step S4 is compared with that calculated in step S4. display -P measure Then, the absolute value is compared with the preset pressure error threshold: if the pressure coupling error is less than or equal to the pressure error threshold, the pressure coupling error index is qualified; if the pressure coupling error is greater than the pressure error threshold, the pressure coupling error index is unqualified.

[0125] Comparison of flow coupling errors:

[0126] The flow coupling error calculated in step S4 Compare with the preset flow coupling error threshold: If If the flow coupling error is ≤ the preset flow coupling error threshold, then the flow coupling error indicator is qualified; if If the preset flow coupling error threshold is not met, the flow coupling error index will be deemed unqualified.

[0127] Comparison of dynamic performance metrics:

[0128] Each dynamic performance index calculated in step S4 is compared with its corresponding preset dynamic performance threshold. Taking a typical dynamic performance index as an example:

[0129] Rise time comparison: The calculated pressure rise time is compared with the preset rise time threshold: If the pressure rise time is less than or equal to the preset rise time threshold, the rise time indicator is qualified; if the pressure rise time is greater than the preset rise time threshold, the rise time indicator is unqualified.

[0130] Comparison of adjustment time: The calculated pressure adjustment time is compared with the preset adjustment time threshold. If the calculated pressure adjustment time is less than or equal to the preset adjustment time threshold, the adjustment time indicator is qualified; if the calculated pressure adjustment time is greater than the preset adjustment time threshold, the adjustment time indicator is unqualified.

[0131] Among them, the established leakage amount The relationship curve between flow coupling error and the calibration curve, and the specific implementation method for calibrating the pneumoperitoneum machine under calibration based on the relationship curve are as follows:

[0132] (1) Set the leakage rate operating range and preset a set of leakage rate operating values ​​to cover the range from no leakage to the maximum expected leakage rate.

[0133] (2) Perform calibration cyclically. For each preset leakage amount, perform the complete calibration process from step S2 to S5 in sequence to obtain the flow coupling error corresponding to each leakage amount and record it as a data pair.

[0134] (3) Establish the relationship curve by performing linear or polynomial fitting on the above data in the coordinate system to obtain the relationship curve.

[0135] (4) Accurate calibration is performed based on the relationship curve. In actual surgical use, the predicted flow coupling error is obtained by substituting the current leakage amount into the relationship curve. The predicted error value is used to correct the flow display value of the pneumoperitoneum machine being calibrated, and the accurately calibrated flow value is obtained.

[0136] Example 2;

[0137] Based on the foregoing embodiments, Embodiment 2 of the present invention provides an application for conventional surgical pneumoperitoneum scenarios:

[0138] In routine surgical pneumoperitoneum scenarios, the pneumoperitoneum machine needs to undergo multi-condition self-traceability calibration to ensure its stable and reliable operation.

[0139] Detailed steps of the method are reported:

[0140] A standard circuit for back pressure loading and controlled leakage injection is constructed: Back pressure loading refers to applying a preset reverse pressure (i.e., back pressure) to the gas output end of the insufflator under calibration through a back pressure loading device in the standard circuit, simulating the resistance of intra-abdominal gas to the airflow output of the insufflator during laparoscopic surgery. In clinical use, the insufflator needs to overcome the existing gas pressure in the abdominal cavity to inflate the abdominal cavity with new gas. The pressure in the abdominal cavity is the back pressure sensed at the output end of the insufflator. The magnitude of the back pressure directly affects the output flow characteristics and pressure control accuracy of the insufflator. In the standard circuit, back pressure loading is achieved by adjusting the opening of the corresponding valves on the pipes constituting the standard circuit. Controlled leakage injection refers to actively injecting a preset amount of gas leakage into the standard circuit through a controlled leakage injection device in the standard circuit, simulating various gas leakage scenarios caused by inadequate sealing around the trocar, frequent entry and exit of surgical instruments, and leakage from the tissue cutting surface during laparoscopic surgery. In actual laparoscopic surgery, absolute sealing of the abdominal cavity is difficult to guarantee, and gas leakage of varying degrees is common. The presence of leakage affects the stable control of intra-abdominal pressure by the insufflator, forcing the insufflator to increase its output flow rate to compensate for the leakage. Therefore, introducing a controllable leakage during calibration is a key method for evaluating the flow compensation capability and system robustness of the insufflator in actual use. In the standard circuit, the injection of a controllable leakage can be achieved as follows: a separate leakage branch is set up in the standard circuit, with one end connected to the simulated intra-abdominal container or main pipeline and the other end connected to the atmosphere or gas recovery device; a leakage regulating valve is installed on the leakage branch, and the amount of leakage is precisely controlled by adjusting the opening of the valve; the amount of leakage is related to the opening of the leakage regulating valve, and the correspondence between the opening and the amount of leakage can be established through experimental calibration.

[0141] Through pipeline and valve design, the valve opening is precisely controlled, and the pressure provided by the back pressure loading device is set to... By adjusting the valve opening To control the precise application of back pressure, The value range is 0-1, where 0 indicates the valve is completely closed and 1 indicates the valve is completely open. Simultaneously, a controllable leakage device is used to inject leakage. Its size is related to the valve opening. Related, can be represented as , This is a constant related to the characteristics of the leakage device.

[0142] Switching between voltage regulation, current regulation, and leakage disturbance conditions within the same sequence:

[0143] The control system switches operating conditions according to a preset sequence and time intervals, first performing a pressure stabilization mode to maintain pressure. Stabilize at the set value The duration is Then switch to constant flow mode to maintain the flow rate. Stabilize at the set value The duration is Finally, a leakage disturbance condition is implemented, introducing a preset leakage amount. Duration is .

[0144] The collaborative setup allows for synchronized readback of traceable pressure and flow references: The traceable pressure reference, in the calibration method of this invention, refers to a high-precision pressure measuring device used to provide a pressure measurement reference standard, whose measured values ​​are traceable to national or international pressure metrology references through an uninterrupted calibration chain. Similarly, the traceable flow reference, in the calibration method of this invention, refers to a high-precision flow measuring device used to provide a flow measurement reference standard, whose measured values ​​are traceable to national or international flow metrology references through an uninterrupted calibration chain.

[0145] Pressure and flow sensors are used, and their traceable calibration certificates are ensured. The pressure value measured by the pressure sensor is... The flow rate measured by the flow sensor is The data is collected and read back in real time through the data acquisition and processing unit.

[0146] Calculate coupling error and dynamic response:

[0147] The coupling relationship between pressure, flow rate, and leakage is analyzed and calculated by establishing a mathematical model.

[0148] The coupling relationship between pressure and flow can be represented by a function. This indicates that the coupling relationship between flow and leakage can be represented by a function. express.

[0149] Based on measured data and Calculate coupling error and By fitting data, the coupling relationship among the three factors is obtained. Data calculations show that by changing the leakage setpoint and repeating the experiment, the variation law of coupling error with leakage amount is analyzed. The relative deviation reflects the deviation between the actual behavior of the pneumoperitoneum system and the ideal coupling model, thereby quantifying the degree of impact of leakage on the system flow control accuracy.

[0150] Simultaneously, the dynamic response during the switching of operating conditions is analyzed, such as the rise time of pressure and flow. and adjustment time .

[0151] Specifically, this involves establishing a mathematical model for the coupling relationship between pressure, flow rate, and leakage:

[0152] 1. Model Physics Foundation:

[0153] The simulated abdominal cavity is considered as a rigid container with a fixed volume V (control volume). According to the law of conservation of mass, the difference between the mass of gas flowing into the container and the mass of gas flowing out of the container per unit time is equal to the increase in the mass of gas inside the container.

[0154] ;

[0155] Where m is the mass of gas in the container, and t is time. and The gas densities at the inlet and outlet are respectively. The output volumetric flow rate of the insufflator. The leakage volume flow rate.

[0156] 2. Steady-state coupling model (used to analyze coupling error):

[0157] In steady state, the system parameters do not change with time, that is... Assuming the gas density at the intake and leakage points is approximately equal ( = Then, from the above equation, we can obtain the steady-state equilibrium equation:

[0158] ;

[0159] In a real system, the required output flow rate of the pneumoperitoneum machine to maintain a certain intra-abdominal pressure P is... Not only used to compensate for leaks It is also related to the system's own pressure and flow characteristics, and the equivalent flow conductance of the system is introduced. The concept of establishing an accurate steady-state model:

[0160] ;

[0161] In the formula, The term reflects the basic flow rate required to overcome system resistance to maintain pressure P, and the system's equivalent conductance. It can be calibrated through experiments.

[0162] 3. Dynamic response model (used to analyze dynamic characteristics):

[0163] When considering the transient process of switching operating conditions, a dynamic model needs to be established. Assuming the gas is an ideal gas and the process is isothermal, the mass m inside the container is proportional to the pressure P (m=k*p). Combining this with the mass conservation equation, a first-order dynamic model can be obtained:

[0164] ;

[0165] Where k is a constant related to the container volume, gas temperature, and type, this equation shows that the rate of change of pressure dP / dt is proportional to the net inflow rate ( ).

[0166] In actual calibration: Used to analyze steady-state coupling errors, for example, by comparing the actual output flow rate of the insufflator under the same set pressure P with and without leakage. This allows for model validation and assessment of the coupling effects of leakage on flow control.

[0167] Leakage When the pressure increases by a step, the change curve of pressure P(t) is monitored, and the formula is used. By fitting the system, the time constant τ=k can be solved, and then the rise time, settling time, etc. can be calculated.

[0168] Will and Substitute the values ​​into the steady-state model formula to calculate the predicted flow rate theoretically required to maintain this state. :

[0169] ;

[0170] Predict traffic Compared with the actual measured flow rate baseline value Compare and calculate the relative deviation :

[0171] ;

[0172] The relative deviation It reflects the deviation between the actual behavior of the system and the ideal coupling model, that is, it includes the flow coupling error caused by system nonlinearity, sensor error, etc.

[0173] By changing the leakage setting value By repeating the experiment, the coupling error can be analyzed. With the amount of leakage The variation pattern can be used to quantify the impact of leakage on the accuracy of system flow control.

[0174] Standard state conversion compensation is performed by combining temperature, gas source pressure, and gas type:

[0175] According to different temperatures Gas source pressure The calibration results are corrected based on the physical characteristics parameters of the gas type. Gas type refers to the type of gas used in the clinical use or calibration testing of the insufflator. Gas type is a crucial factor affecting the measurement performance of the insufflator; different gases, due to differences in their thermodynamic properties and physical properties (density, viscosity, compressibility factor, etc.), have varying impacts on the pressure control and flow output characteristics of the insufflator. In this invention, gas types are divided into two main categories based on their thermodynamic properties and applicable gas state equations: conventional gases and special gases. Conventional gases can include carbon dioxide: the most commonly used insufflator gas in clinical laparoscopic surgery, which has advantages such as being colorless and odorless, non-flammable and explosive, highly soluble in blood, and easily absorbed and excreted by the body. This is the default conventional gas type in this invention. Other commonly used inert gases include: other gases that may be used when carbon dioxide is not applicable. Special gases can include helium: an insufflator gas that may be used in certain special surgeries, with a small molecular weight and strong diffusivity; and a mixture of carbon dioxide and helium: a mixture formulated to balance the absorbability of carbon dioxide and the stability of helium. Other inert gases or gas mixtures: pneumoperitoneum gases used for specific clinical needs.

[0176] Generates automated reports and audit logs that include coverage conditions, residuals, and uncertainties:

[0177] Based on the above calculations and analysis results, an automatic report is generated, which includes the covered operating conditions (voltage regulation, current regulation, leakage disturbance) and residuals (coupling errors). and and uncertainty .

[0178] Uncertainty can be calculated based on the standard deviation of the measurement data and the sources of uncertainty in the calibration method, using the following formula:

[0179]

[0180] in, Let U be the uncertainty component, and U be the uncertainty of the calibration result, where 1 ≤ j ≤ w, and the value of w is adjusted according to the actual situation.

[0181] In the calibration method of the present invention, the measurement uncertainty components of the calibration result uncertainty mainly include the following categories:

[0182] 1. Measurement uncertainty introduced by the pressure reference: This component originates from the measurement inaccuracies of the traceable pressure reference itself. Acquisition method: Based on the expanded uncertainty U given in the pressure reference's calibration certificate. P and inclusion factor K P Calculate the standard uncertainty u of the pressure reference.Pstd :u Pstd =U P / K P .

[0183] 2. Measurement uncertainty introduced by the flow rate reference: This component originates from the measurement inaccuracies of the traceable flow rate reference itself. Acquisition method: Based on the expanded uncertainty U given in the calibration certificate of the flow rate reference. Q and inclusion factor K Q Calculate the standard uncertainty u of the flow rate reference. Qstd :u Qstd =U Q / K Q .

[0184] 3. Uncertainty introduced by environmental factors, which further includes the following sub-components:

[0185] (1) Uncertainty introduced by temperature measurement, source explanation: originates from the measurement error of the temperature sensor. The temperature measurement value is used for standard state conversion, and its error will be transmitted to the converted pressure reference value and flow reference value. Acquisition method: according to the technical specifications or calibration certificate of the temperature sensor, obtain its maximum permissible error and process it as a uniform distribution: the uncertainty introduced by temperature measurement is equal to the absolute value of the maximum permissible error divided by a constant.

[0186] (2) Uncertainty introduced by air source pressure fluctuation: The uncertainty originates from the fluctuation of air source pressure during the calibration process. The instability of air source pressure will affect the output of the pneumoperitoneum machine being calibrated, thereby affecting the calibration results. The uncertainty introduced by air source pressure fluctuation can be obtained by existing methods of multiple measurements, which will not be elaborated upon in this embodiment of the invention.

[0187] (3) Uncertainty introduced by gas physical property parameters, source explanation: originates from the reference error of the gas physical property parameters used (such as molar mass, density, compressibility factor, etc.). When the gas type is a special gas, the constants in its equation of state (such as van der Waals constant) The compressibility factor (r) and compressibility factor (k) also have certain reference uncertainties. Acquisition method: Obtain the standard uncertainty of each parameter based on the data source of the gas physical property parameters (such as a standard gas datasheet), or perform a Type B assessment based on the maximum permissible error of the parameter reference value.

[0188] (4) Uncertainty introduced by fitting calibration coefficients: The source is the fitting inaccuracy reflected by the fitting residuals when generating calibration coefficients through function fitting in step S5.2. Acquisition method: Calculated based on the residuals of least squares fitting. The specific calculation method is not described in detail in this embodiment of the invention.

[0189] (5) Uncertainty introduced by measurement repeatability, source explanation: originates from the dispersion of measurement results when repeated measurements are performed multiple times under the same conditions. Acquisition method: under steady-state conditions (such as the stable stage of voltage stabilization), the same measurand is repeatedly measured multiple times, and then calculated using existing calculation methods. The specific calculation method will not be elaborated in this embodiment of the invention.

[0190] Example 3;

[0191] Based on the foregoing embodiments, Embodiment 3 of the present invention provides an application for complex surgical pneumoperitoneum scenarios (the main difference between the application for complex surgical scenarios and the scenarios in Embodiment 2 is that they involve multiple organ operations or long-term surgeries, the working conditions of the pneumoperitoneum machine are more complex, and more accurate multi-condition self-traceability calibration is required; Embodiment 2 is the ideal state of stable pressure).

[0192] In complex surgical pneumoperitoneum scenarios, such as those involving multiple organ operations or prolonged surgeries, the working conditions of the pneumoperitoneum machine become more complex, requiring more precise multi-condition self-traceability calibration.

[0193] Method and steps:

[0194] Construct a standard loop for back pressure loading and controlled leak injection:

[0195] Design more complex piping and valve systems to meet the requirements of different back pressures and leakage rates.

[0196] Pressure provided by the back pressure loading device It is adjustable within a certain range, and the adjustment range is... By adjusting the opening degree of multiple valves , ,..., To precisely control the loading of back pressure and the injection of leakage, where n is the number of valves and the leakage rate. It can be represented as , These are constants related to the characteristics of each leakage device.

[0197] Switching between voltage regulation, current regulation, and leakage disturbance conditions within the same sequence:

[0198] The control system switches operating conditions according to different stages and needs of the surgery, following a more complex preset sequence and time intervals. At the beginning of the surgery, it first enters a pressure stabilization mode to maintain pressure. Stabilize at a lower setting value The duration is As the surgery progresses, the system switches to steady flow mode to maintain the flow rate. Stabilize at a higher set value Duration is During critical surgical procedures, leakage disturbance conditions are introduced, thereby stimulating a larger, pre-set leakage volume. The duration is At the end of the surgery, the system switches back to pressure stabilization mode to maintain pressure. Stabilize at a lower setting value The duration is .

[0199] Parallel arrangement allows for simultaneous readback of traceable pressure and flow references:

[0200] Higher precision pressure and flow sensors are used, with measurement accuracies reaching ±0.1% and ±0.2% respectively. The pressure value measured by the pressure sensor is... The flow rate measured by the flow sensor is The data is collected and read back in real time at a higher sampling frequency through the data acquisition and processing unit.

[0201] Calculate coupling error and dynamic response:

[0202] An accurate mathematical model is established to describe the coupling relationship between pressure, flow rate, and leakage, taking into account the non-ideal nature of the gas, and using the van der Waals equation. To analyze the relationship between pressure and flow. and For the constants related to the properties of the gas, P is the pressure (in Pa), V is the volume (in m³), ​​n is the amount of substance (in mol), R is the gas constant (general value R≈8.314 J / (mol⋅K)), and T is the thermodynamic temperature (in K Kelvin, T=t+273.15).

[0203] Based on measured data and Calculate coupling error and And analyze dynamic response characteristics, such as pressure and flow overshoot. and peak time .

[0204] Standard state conversion compensation is performed by combining temperature, gas source pressure, and gas type:

[0205] The impact of dynamic changes in temperature and gas source pressure on the calibration results is considered.

[0206] Temperature changes over time The change of gas source pressure over time is .

[0207] Based on the physical property parameters of different gas types, such as molar mass Specific heat capacity The calibration results are then corrected. For flow rate conversion, in addition to considering the effects of temperature and pressure, the influence of gas type on the flow coefficient must also be taken into account. The converted flow rate... , Let be the specific heat capacity of the gas under standard conditions, where Standard temperature value, This refers to the actual gas temperature value measured by the temperature sensor during actual flow measurement.

[0208] Generates automated reports and audit logs that include coverage conditions, residuals, and uncertainties:

[0209] Based on detailed calculations and analysis, a more comprehensive automatic report is generated. The report not only includes the covered operating conditions, residuals, and uncertainties, but also compares and analyzes the calibration results under different operating conditions to evaluate the performance stability of the pneumoperitoneum machine under different working conditions.

[0210] Example 4;

[0211] Based on the foregoing embodiments, Embodiment 4 of the present invention provides an application for special gas pneumoperitoneum scenarios:

[0212] In certain specialized surgeries, it may be necessary to use special gases (such as a mixture of helium and carbon dioxide) for pneumoperitoneum, which places higher demands on the calibration of the pneumoperitoneum machine.

[0213] Method and steps:

[0214] Construct a standard circuit for back pressure loading and controlled leakage injection: Design a special standard circuit for the characteristics of special gases. The physical properties of special gases, such as viscosity and density, are different from those of conventional gases, so it is necessary to adjust the pipe diameter and valve type.

[0215] The viscosity of the special gas is The density is Based on the principles of fluid mechanics, select an appropriate pipe diameter. This is to ensure that the gas flow conditions meet the requirements.

[0216] By adjusting the valve opening To control the back pressure loading and leakage injection, leakage amount The calculation needs to consider the physical properties of the special gas, which can be expressed as: , These are constants related to the leakage device and gas characteristics. This represents the pressure difference before and after the valve.

[0217] Switching between voltage regulation, current regulation, and leakage disturbance conditions within the same sequence:

[0218] The control system switches operating conditions according to the requirements of the special gas pneumoperitoneum, following a specific sequence and time interval.

[0219] First, establish a pressure stabilization mode to maintain the pressure. Stabilize at the set value suitable for special gas pneumoperitoneum The duration is Then switch to constant flow mode to maintain the flow rate. Stabilize at a set value that matches the special gas supply. The duration is Finally, a leakage disturbance condition is implemented, introducing a preset leakage amount. To simulate potential leakage during actual surgery, the duration is... .

[0220] Parallel arrangement allows for simultaneous readback of traceable pressure and flow references:

[0221] Select high-precision pressure and flow sensors suitable for measuring special gases.

[0222] Because special gases may have special requirements for sensor materials, it is necessary to select sensors with good compatibility.

[0223] The pressure value measured by the pressure sensor is The flow rate measured by the flow sensor is These data are collected and read back in real time through the data acquisition and processing unit.

[0224] Calculate coupling error and dynamic response:

[0225] A mathematical model considering the physical properties of special gases is established to analyze the coupling relationship between pressure, flow rate and leakage.

[0226] Special gases have different thermophysical properties than conventional gases, and their thermal conductivity, diffusion coefficient, and other factors need to be considered when modeling them.

[0227] Based on measured data and Calculate coupling error and And analyze dynamic response characteristics, such as the response time of pressure and flow. and stable time .

[0228] Standard state conversion compensation is performed by combining temperature, gas source pressure, and gas type:

[0229] The physical properties of special gases vary more complexly with temperature and pressure, thus requiring more accurate conversion and compensation methods.

[0230] The equation of state for special gases is , For a function related to the gas state, based on this equation of state and the measured temperature... Gas source pressure Parameters such as these are used to correct the calibration results.

[0231] For pressure conversion, the compressibility of special gases is taken into account, and the converted pressure is... , and These are the compressibility factors of the gas under standard and measured conditions, respectively.

[0232] Generates automated reports and audit logs that include coverage conditions, residuals, and uncertainties:

[0233] Based on the calibration results of the special gas pneumoperitoneum, a detailed automated report is generated. The report focuses on analyzing the impact of the special gas on the calibration results and evaluating the performance and reliability of the pneumoperitoneum machine when using the special gas.

[0234] Example 5;

[0235] Based on the foregoing embodiments, Embodiment 5 of the present invention provides a multi-condition self-traceable calibration system for insufflators. The system is based on the aforementioned multi-condition self-traceable calibration method for insufflators, and includes:

[0236] The standard loop construction module includes pipes, valves, and a back pressure loading device, which is used to construct a standard loop. By controlling the opening of the valves, it can apply back pressure to the pneumoperitoneum machine under calibration and inject a controllable amount of leakage.

[0237] The working condition switching module includes a control system and an actuator, which is used to control the pneumoperitoneum machine being calibrated to enter and maintain preset pressure stabilization working condition, flow stabilization working condition and leakage disturbance working condition in a preset order and time interval during a continuous calibration process.

[0238] The reference reading module includes traceable pressure and flow references, as well as a data acquisition and processing unit, for synchronously acquiring and comparing the measured values ​​of the pressure reference, the measured values ​​of the flow reference, and the readings of the pneumoperitoneum machine being calibrated.

[0239] The calculation module is used to calculate pressure coupling error, flow coupling error, and dynamic response characteristics based on synchronously acquired data;

[0240] The compensation module is used to input measured ambient temperature, gas source pressure and gas type data for standard state conversion, and generate calibration coefficients and performance qualification results;

[0241] The report generation module is used to generate automatic reports and audit logs that include the covered operating conditions, residuals, final calibration measurement results, and calibration result uncertainties.

[0242] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0243] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A multi-condition self-traceable calibration method for insufflators, characterized in that, Includes the following steps: S1: Construct a standard loop, which is used to apply back pressure to the pneumoperitoneum machine under calibration and inject a controlled leakage amount; S2: During a continuous calibration process, the pneumoperitoneum machine under calibration is controlled to sequentially enter and maintain preset pressure stabilization, flow stabilization, and leakage disturbance conditions. Through the traceable pressure reference and flow reference in the standard circuit working in concert, the measured values ​​of the pressure reference, the flow reference, and the pneumoperitoneum machine under calibration are continuously and synchronously collected throughout the entire calibration process. S3: Compare the measured values ​​of the pressure reference and the flow reference collected at the same time with the pressure value and flow value in the measured values ​​of the pneumoperitoneum machine being calibrated, respectively, to obtain calibration data; S4: Calculate pressure coupling error and flow coupling error based on calibration data; calculate dynamic response characteristics based on transient data during operating condition switching using a dynamic response model; S5: Based on the measured ambient temperature, gas source pressure, and gas type data, the measured values ​​of the pressure reference and the flow reference are adjusted according to a preset standard pressure. and preset standard temperature The standard state is converted to obtain the pressure reference value and flow reference value under the standard state; the pressure reference value and flow reference value are fitted with the corresponding values ​​in the measured values ​​of the pneumoperitoneum machine under calibration to generate calibration coefficients; the measured values ​​of the pneumoperitoneum machine under calibration are corrected using the calibration coefficients to obtain the final calibration measurement result; the pressure coupling error, the flow coupling error and the dynamic response characteristic are compared with their respective preset criterion thresholds to generate a judgment result on whether the performance of the pneumoperitoneum machine under calibration is qualified; S6: Generate an automatic report and audit record. The report includes the operating condition type, residual, final calibration measurement result, and calibration result uncertainty covered in step S2. The residual is obtained through the pressure coupling error and the flow coupling error. The calibration result uncertainty is obtained by combining the measurement uncertainty of the pressure reference and the flow reference, the uncertainty introduced by environmental factors, and the fitting uncertainty of the calibration coefficient.

2. The multi-condition self-traceable calibration method for insufflators according to claim 1, characterized in that, The flow coupling error is calculated by establishing a steady-state coupling model based on the law of conservation of mass, specifically including: The steady-state coupling model is as follows: ； Where, 𝑄 is the flow rate, 𝑃 is the pressure, 𝐿 is the leakage rate, and 𝐶 is the system equivalent conductance calibrated through experiments; For the preset standard pressure and the set leakage amount Substituting into the steady-state coupling model, the predicted flow rate used to maintain this state is calculated. ; The measured value of the flow reference With the predicted flow Compare and calculate the relative deviation : ； Based on the relative deviation Obtain the flow coupling error.

3. The multi-condition self-traceable calibration method for insufflators according to claim 1, characterized in that, Dynamic response characteristics are calculated using a dynamic response model, including: Based on the law of conservation of mass, a dynamic response model describing the rate of change of pressure over time is established. The formula for the dynamic response model is as follows: ； Where, 𝑘 is a constant related to container volume, gas temperature and type, 𝑄 is flow rate, 𝑃 is pressure, 𝐿 is leakage, and t is time; During the transient process of switching operating conditions, based on the measurement data synchronously collected from the pressure reference and flow reference, the dynamic performance index, which includes at least the pressure or flow rise time and the adjustment time, is calculated and output using the dynamic response model. The dynamic performance index is used as a quantitative representation of the dynamic response characteristics.

4. The multi-condition self-traceable calibration method for insufflators according to claim 1, characterized in that, Step S5 specifically includes: S5.1: Based on the gas law and gas molar mass or density parameters, the measured values ​​of the pressure reference and the flow reference, combined with the measured ambient temperature, gas source pressure, and gas type, are converted to the preset standard pressure. and preset standard temperature Status, obtain pressure and flow reference values ​​under standard conditions; S5.2: The pressure reference value and flow reference value under the standard state are respectively fitted with the corresponding values ​​in the measured values ​​of the insufflator under calibration to generate pressure calibration coefficient and flow calibration coefficient for correcting the measured values ​​of the insufflator. S5.3: Using the pressure calibration coefficient and the flow calibration coefficient, the pressure measurement value and flow measurement value of the insufflator under the corresponding operating conditions are corrected respectively to obtain the final calibration measurement result; S5.4: Compare the pressure coupling error, flow coupling error, and dynamic performance index with their respective preset criterion thresholds to generate a judgment result on whether the performance of the pneumoperitoneum machine is qualified.

5. The multi-condition self-traceable calibration method for insufflators according to claim 4, characterized in that, Step S5 also includes: Change the set leakage amount Repeat steps S2 to S5 until the preset leakage range is covered, obtain the flow coupling error under different leakage rates, and establish the set leakage rate. The relationship curve between the flow rate coupling error and the calibration curve is used to calibrate the pneumoperitoneum machine being calibrated.

6. The multi-condition self-traceable calibration method for insufflators according to claim 4, characterized in that, The conversion method in step S5.1 specifically includes: When the gas type is a special gas, the van der Waals equation is used to describe the relationship between the gas's pressure, volume, and temperature. The van der Waals equation is as follows: ； Where, 𝑎 and 𝑏 are constants related to gas properties, 𝑃 is pressure, V is volume, n is amount of substance, R is gas constant, and T is thermodynamic temperature; For pressure conversion, the compressibility factor of the special gas under standard conditions is used. Compressibility factor under measured conditions The converted pressure reference value is calculated. 𝑟𝑒𝑓 The calculation method is as follows: ； in, For actual measured temperature, The measured value of the pressure reference.

7. The multi-condition self-traceable calibration method for insufflators according to claim 1, characterized in that, The generation of automatic reports and audit logs in step S6 also includes: The calibration results include the final calibration measurement results and the judgment results; The calibration results obtained under different working conditions are compared and analyzed to evaluate the performance stability of the calibrated pneumoperitoneum machine under different working conditions, and the comparison and analysis results are incorporated into the automatic report and audit record.

8. The multi-condition self-traceable calibration method for insufflators according to claim 1, characterized in that, In step S1, the applied back pressure and the amount of leakage are controlled by adjusting the opening of the valve on the pipeline in the standard circuit.

9. A multi-condition self-traceable calibration method for insufflators according to claim 1, characterized in that, In step S2, the control system sequentially switches and maintains the voltage stabilization condition, the current stabilization condition, and the leakage disturbance condition according to a preset sequence and time interval.

10. A multi-condition self-traceable calibration system for insufflators, characterized in that, The system is based on a multi-condition self-traceable calibration method for pneumoperitone machines according to any one of claims 1 to 9, and the system includes: The standard loop construction module includes pipes, valves, and a back pressure loading device, which is used to construct a standard loop. By controlling the opening of the valves, it can apply back pressure to the pneumoperitoneum machine under calibration and inject a controllable amount of leakage. The working condition switching module includes a control system and an actuator, which is used to control the pneumoperitoneum machine being calibrated to enter and maintain preset pressure stabilization working condition, flow stabilization working condition and leakage disturbance working condition in a preset order and time interval during a continuous calibration process. The reference reading module includes traceable pressure and flow references, as well as a data acquisition and processing unit, for synchronously acquiring and comparing the measured values ​​of the pressure reference, the measured values ​​of the flow reference, and the readings of the pneumoperitoneum machine being calibrated. The calculation module is used to calculate pressure coupling error, flow coupling error, and dynamic response characteristics based on synchronously acquired data; The compensation module is used to input measured ambient temperature, gas source pressure and gas type data for standard state conversion, and generate calibration coefficients and performance qualification results; The report generation module is used to generate automatic reports and audit logs that include the covered operating conditions, residuals, final calibration measurement results, and calibration result uncertainties.

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