A blood pressure simulator repeatability calibration method and calibration device

Abstract

The application relates to the technical field of blood pressure simulator calibration, and discloses a blood pressure simulator repeatability calibration method and a calibration device, which comprises the following steps: locking static pressure through micro-volume adjustment of a pressure building cylinder to evaluate signal stability; utilizing dynamic compensation of pressure building cylinder volume and pressure reducing valve opening degree adjustment to make the gas path pressure linearly and uniformly decrease at a set rate, and synchronously collecting full envelope data; adopting a numerical fitting algorithm to construct an envelope model to position actual average pressure; repeatedly performing multiple measurements and calculating experimental standard deviation to obtain repeatability results. The device comprises a host computer, a mainboard, a driver and a gas path system, wherein a gas pump, a gas capacitor and a pressure increasing valve are connected in series in the gas path system, and a pressure reducing valve, a pressure building cylinder and a high-precision module are connected in parallel in a common gas path. Through the cooperative control of the pressure building cylinder and the pressure reducing valve, the application solves the problem of pressure reducing nonlinearity, improves the accuracy of actual average pressure positioning and the precision of repeatability evaluation.

Description

Technical Field

[0001] This invention relates to the field of blood pressure simulator calibration technology, specifically to a method and apparatus for calibrating the repeatability of a blood pressure simulator. Background Technology

[0002] Blood pressure simulators, as metrological standard instruments capable of simulating human blood pressure physiological signals, are widely used in the verification and calibration of non-invasive automatic blood pressure monitors. To ensure the accuracy and stability of the blood pressure simulator's output signal, its repeatability needs to be calibrated periodically, especially its repeatability during dynamic blood pressure reduction.

[0003] Existing calibration devices typically employ an air pump as the pressure source, combined with a proportional valve or solenoid valve for exhaust control. During dynamic pressure reduction calibration, the device releases gas from the gas path by adjusting the valve opening. However, the gas flow rate through the valve is constrained by the physical characteristics of the pressure difference between the inside and outside of the gas path. As the internal pressure of the gas path decreases, the pressure difference gradually diminishes, causing the gas discharge rate to naturally decrease over time under single valve control. This results in a non-linear exponential decrease in the pressure reduction curve, characterized by a rapid initial decrease followed by a slower, more gradual decline.

[0004] Since blood pressure simulators mostly operate on the oscillometric principle, their core function is to extract the pulse wave oscillation envelope during the linear change of static pressure. The aforementioned nonlinear pressure reduction process leads to inconsistent sampling densities of pulse wave signals on the time axis across different pressure ranges, causing distortion in the envelope curve fitting and thus affecting the accuracy of the mean arterial pressure (MAP) measurement. Furthermore, in the static pressure testing phase, traditional valve control methods struggle to accurately compensate for the thermal expansion of gas after adiabatic compression or minor leaks in the pipeline, easily leading to static pressure baseline drift. This interferes with the accurate assessment of the short-term stability of the blood pressure simulator's pulse wave amplitude, limiting the overall evaluation capability of the calibration device. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and device for calibrating the repeatability of a blood pressure simulator, which solves the problems of discontinuous control trajectory, static and unadjustable emotion mapping, lack of user feedback closed loop, weak adaptive capability, and insufficient fusion of multi-dimensional control information in existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for calibrating the repeatability of a blood pressure simulator.

[0008] This method first performs static pressure locking and stability assessment. The mainboard controls the air pump and pressure boosting valve to fill the common air circuit via a driver. After the air pump stops running, the pressure in the air circuit is locked at the preset target static pressure using the micro-volume adjustment function of the pressure-building cylinder. This process uses an imported high-precision module to collect pulse wave data generated by the blood pressure simulator and evaluates the signal stability under static pressure. By making small changes to the air circuit volume through the pressure-building cylinder, pressure drift caused by gas thermal effects or minor leaks is compensated for, establishing a stable test benchmark.

[0009] After the signal stability meets the preset conditions, the dynamic linear pressure reduction and data acquisition stage begins. The control gas path is inflated to an initial pressure higher than the systolic pressure. Through the coordinated action of adjusting the opening of the pressure-reducing valve and the dynamic volume compensation of the pressure-generating cylinder, the pressure within the gas path decreases linearly and uniformly at a set rate. During this process, the imported high-precision module simultaneously acquires full-envelope data including real-time static pressure values ​​and pulse wave amplitude values. This step provides a coarse-adjustment exhaust channel through the pressure-reducing valve and uses the movement of the pressure-generating cylinder piston to change the overall volume of the gas path, compensating for the natural decay of gas flow rate as the pressure difference decreases, thereby maintaining a constant pressure change rate.

[0010] Subsequently, a numerical fitting algorithm was used to process the full envelope data. An envelope model of pulse wave amplitude variation with static pressure was constructed, and the actual mean pressure of the measurement was located based on this model. This processing method can reconstruct continuous physiological signal features from discrete sampling points, improving the resolution of feature point identification.

[0011] Finally, the control system repeatedly performs the above-described linear uniform descent and actual mean pressure positioning steps multiple times. The experimental standard deviation of the obtained multiple actual mean pressure values ​​is calculated, and this experimental standard deviation is used as the repeatability result of the blood pressure simulator. Through multi-sample statistical analysis, random errors from single measurements are eliminated, and the repeatability of the tested device is quantified.

[0012] Furthermore, the step described above, which utilizes the micro-volume adjustment function of the pressure-generating cylinder to lock the pressure in the air circuit at a preset target static pressure, employs closed-loop feedback control. After the air circuit pressure approaches the target static pressure and the air pump stops operating, the main board calculates the volume compensation amount using a PID control algorithm or a fuzzy control algorithm based on the deviation between the real-time pressure value fed back by the imported high-precision module and the target static pressure. When the real-time pressure value is less than the target static pressure, the piston in the pressure-generating cylinder is controlled to move in the compression direction to reduce the total air circuit volume; when the real-time pressure value is greater than the target static pressure, the piston is controlled to move in the expansion direction to increase the total air circuit volume, thereby achieving precise maintenance of the static pressure.

[0013] Furthermore, the steps for evaluating signal stability under static pressure include extracting multiple consecutive complete pulse wave waveforms, measuring the difference between the peak and trough values ​​of each pulse wave waveform as the pulse wave amplitude, and obtaining a measurement sequence. The arithmetic mean and experimental standard deviation of all pulse wave amplitudes in the measurement sequence are calculated, and the ratio of the experimental standard deviation to the arithmetic mean is calculated as the relative repeatability. The relative repeatability is compared with a preset threshold. If the relative repeatability is less than or equal to the preset threshold, the signal stability is determined to meet the preset conditions, allowing the process to proceed to the subsequent dynamic calibration procedure.

[0014] Furthermore, the aforementioned steps, which involve the coordinated action of adjusting the opening of the pressure-reducing valve and dynamically compensating for the volume of the pressure-generating cylinder, employ a dual compensation mechanism for rate deviation. The main board determines the target pressure reduction rate based on preset pressure reduction level parameters and controls the pressure-reducing valve to open and release air. The actual pressure reduction rate of the gas path is periodically calculated and compared with the target pressure reduction rate. On one hand, the effective opening of the pressure-reducing valve is adjusted and flow loss is compensated based on the comparison results; on the other hand, the piston movement within the pressure-generating cylinder is controlled according to the rate deviation: when it is necessary to increase the pressure reduction rate, the pressure-generating cylinder is controlled to perform an expansion movement; when it is necessary to suppress the pressure reduction rate, the pressure-generating cylinder is controlled to perform a contraction movement, ensuring that the pressure change rate remains constant.

[0015] Furthermore, the aforementioned step of simultaneously acquiring full-envelope data including real-time static pressure values ​​and pulse wave amplitudes utilizes an imported high-precision module to continuously capture composite pressure signals within the gas path at a high sampling rate. Through digital signal processing technology, a low-pass filtering algorithm is used to filter out high-frequency pulsating components from the composite pressure signal, extracting the real-time static pressure value at each moment. A high-pass or band-pass filtering algorithm is used to filter out the static pressure baseline from the composite pressure signal, extracting the pulse wave oscillation signal at each moment and calculating its peak-to-peak value as the pulse wave amplitude. The real-time static pressure value and pulse wave amplitude at the same moment are associated, bound, and stored until the gas path pressure drops below a preset termination pressure value.

[0016] Furthermore, the steps described above, which involve processing the full envelope data and locating the actual mean pressure using a numerical fitting algorithm, eliminate the time dimension variable from the full envelope data, constructing a discrete point set with static pressure as the x-axis and pulse amplitude as the y-axis. A high-order polynomial is fitted to the discrete point set using the least squares method to generate a continuous envelope curve function. The first derivative of the envelope curve function with respect to pressure is calculated, and the roots with zero derivative are solved numerically. The roots are then subjected to second derivative analysis to identify the maxima, and the static pressure value corresponding to these maxima is determined as the actual mean pressure.

[0017] Furthermore, in the step of calculating the experimental standard deviation of the multiple actual average pressure values ​​obtained above, after each cycle of measurement, the calculated actual average pressure values ​​are stored in a data queue. When the number of cycle measurements reaches a preset value, the arithmetic mean of all actual average pressure values ​​in the data queue is calculated. The sum of squares of the deviations of each actual average pressure value in the data queue from the arithmetic mean is calculated using the Bessel formula, and the sum of squares of the deviations is divided by the square root of the number of measurements minus one to obtain the experimental standard deviation.

[0018] Furthermore, before controlling the air pump and pressure boosting valve to charge the common air circuit, an initialization step is included. The pressure reducing valve is kept fully open, allowing the common air circuit to connect with the external atmosphere through the exhaust port. Under normal pressure, the output signal of the inlet high-precision module is continuously acquired, and a sensor zero-point calibration algorithm is executed to mark the current detected value as the zero-point reference for the system's relative pressure, thereby eliminating sensor zero-point drift error.

[0019] In a second aspect, the present invention provides a blood pressure simulator repeatability calibration apparatus for performing the above-described calibration method.

[0020] The device mainly consists of a main unit, a pneumatic system, and an electrical control system. The main unit serves as a supporting structure, with a handle on top, an LCD screen and a USB port on the front, and a PC communication port, a main power switch, and a charging port on the rear. The side of the main unit has an exhaust port and a rotating arm for connecting to the blood pressure simulator to be calibrated; the rotating arm integrates interface one and interface two.

[0021] The electrical control system includes a motherboard and a driver that are electrically connected inside the host. The host also contains a battery and a power module that is connected to a charging port and supplies power to the motherboard and the driver.

[0022] The pneumatic system is located inside the main unit and adopts a closed-loop control architecture. It includes an air pump, air container, and pressure boosting valve connected sequentially. The output of the pressure boosting valve is connected to a common pneumatic circuit, which is ultimately connected to interface one and interface two. A pressure reducing valve, a pressure generating cylinder, an imported high-precision module, and a spare high-precision module are also connected in parallel on the common pneumatic circuit.

[0023] In terms of connection, the electrical control terminals of the air pump, pressure boosting valve, pressure reducing valve and pressure cylinder are respectively connected to the driver, the signal output terminals of the imported high-precision module and the spare high-precision module are connected to the main board, and the exhaust terminal of the pressure reducing valve is connected to the exhaust port.

[0024] Furthermore, the pressure-generating cylinder is a variable-volume pressure fine-tuning actuator, which internally contains a piston assembly driven by a motor. The main board is configured to send commands to the driver to control the pressure-generating cylinder to compensate for pressure fluctuations through piston displacement in static pressure maintenance mode, and to correct the linearity of the pressure drop rate through uniform or variable-speed piston movement in dynamic pressure reduction mode.

[0025] This invention provides a method and apparatus for calibrating the repeatability of a blood pressure simulator. It offers the following advantages: 1. This invention solves the nonlinear problem of natural gas flow rate decay in the low-pressure section of the traditional gas path due to the reduction of pressure difference by coordinating the adjustment of the pressure reducing valve opening and the dynamic compensation of the pressure building cylinder volume. During the dynamic pressure reduction process, the pressure building cylinder can actively adjust the gas path volume according to the real-time rate deviation to physically compensate for the flow loss, so that the system pressure can strictly decrease linearly according to the set constant rate. This ensures the consistency of the time window for pulse wave recognition of the blood pressure simulator in different pressure ranges, avoids feature point drift caused by the fluctuation of the pressure reduction rate, and thus improves the accuracy of the actual average pressure positioning.

[0026] 2. This invention utilizes the micro-volume servo adjustment function of the pressure-generating cylinder to achieve precise locking and maintenance of static pressure. During the static holding phase after the air pump stops charging, the device can automatically compensate for pressure fluctuations caused by gas thermodynamic effects or minor pipeline leaks through the slight displacement of the piston inside the pressure-generating cylinder. This provides a highly stable physical benchmark for short-term stability assessment of pulse wave amplitude, eliminates the interference of pressure baseline drift on weak pulse signal extraction, and ensures accurate determination of equipment status before the calibration process is started, preventing subsequent misjudgments due to unstable signal sources.

[0027] 3. This invention employs a numerical fitting and extreme value search algorithm based on full envelope data, overcoming the limitations of traditional discrete sampling methods on measurement resolution. By constructing a continuous polynomial envelope model from the collected discrete pulse wave data and using derivative calculations to locate extreme points, the system can accurately capture the actual average pressure position between sampling points. This avoids the drawback of the single-point maximum value method being greatly affected by random sampling noise. Combined with the statistical processing logic of multi-cycle measurement, it can more objectively and realistically quantify the repeatability of the blood pressure simulator's readings, ensuring that the calibration results meet the requirements of high-precision metrology standards. Attached Figure Description

[0028] Figure 1 This is a wireframe diagram of the internal structure of the present invention; Figure 2 This is a schematic diagram of the host structure of the present invention; Figure 3 This is the front view of the present invention; Figure 4 This is the left view of the present invention; Figure 5 This is a rear view of the present invention; Figure 6 This is a top view of the present invention; Figure 7 This is the main control logic flowchart of the present invention. Figure 8 This is a pressure linearity comparison curve of the present invention; Figure 9 This is a discrete distribution diagram of the pulse wave envelope fitting curve of the present invention; Figure 10 This is a comparison diagram of the overlapping pulse wave envelope fitting curves of the present invention.

[0029] The components include: 1. Main unit; 2. Driver; 3. Motherboard; 4. Battery; 5. Air container; 6. Air pump; 7. Backup high-precision module; 8. Pressure cylinder; 9. Imported high-precision module; 10. Pressure boosting valve; 11. Pressure reducing valve; 12. Power module; 13. Rotary arm; 14. LCD display; 15. Interface 1; 16. Interface 2; 17. Handle; 18. PC communication port; 19. Main switch; 20. Charging port; 21. Exhaust port; 22. USB interface. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] See attached document Figure 1 To be continued Figure 4 The present invention provides a method and device for calibrating the repeatability of a blood pressure simulator. The calibration method is performed by a calibration device, which mainly includes a host 1, a human-machine interface component, and an airway connection interface component.

[0032] The main unit 1 forms the main support structure of the device, used to install and protect the internal pneumatic system and control circuitry. Its outer casing is made of rigid material for protection. A handle 17 is located on the top of the main unit 1, with both ends fixed to the upper surface of the casing for moving and carrying the calibration device. An LCD screen 14 is located on the front of the main unit 1, electrically connected to the main board 3 inside the device, used to display pressure values, pulse wave curves, and calibration result data in real time. A USB interface 22 is located on the lower front of the main unit 1, connected to the main board 3, used to connect an external storage device to export calibration data or connect other peripherals.

[0033] A main switch 19, a charging port 20, and a PC communication port 18 are located on the rear facade of the main unit 1. The main switch 19 is connected in series in the power circuit and is used to control the on / off state of the device's main power supply. The charging port 20 is electrically connected to the internal power module 12 and battery 4 and is used to connect to an external power source to charge the device. The PC communication port 18 is used to establish a data communication link between the device and a host computer to realize command transmission and data interaction. An exhaust port 21 is provided on the side shell of the main unit 1, which connects the internal cavity of the device to the external atmosphere and is used for gas discharge and heat dissipation during internal air pressure reduction.

[0034] To facilitate the establishment of an air circuit connection with the device under test, a rotating arm 13 is provided on the right side of the main unit 1. One end of the rotating arm 13 is hinged or fixed to the side of the main unit 1, serving as the mounting carrier for the air circuit interface. Interface 15 and Interface 2 16 are integrated on the rotating arm 13. These two interfaces are connected to the internal air circuit system of the main unit 1 via flexible hoses. Interface 15 uses an M20×1.5 thread and is configured as a standard pressure channel in the air circuit, used to connect to an external standard pressure module for measurement traceability or as a standard pressure output terminal. Interface 2 16 uses a 06 barbed connector and serves as a working interface, used to airtightly connect to the blood pressure simulator to be calibrated via a flexible hose, transmitting the excitation pressure signal generated by the device to the blood pressure simulator and receiving the pulse wave signal fed back by the blood pressure simulator.

[0035] See attached document Figure 1 In this embodiment of the invention, a closed-loop precision air circuit control system is built inside the device. The system mainly consists of a pressure generating unit, a pressure regulating execution unit, and a signal feedback unit. The units are connected to each other through airtight air pipes to form a common air circuit, which eventually converges to interface 15 and interface 16 on the rotating arm 13.

[0036] In the pressure generating unit, air pump 6 serves as the primary pressure source, with its output connected to the input of air container 5 via an air pipeline. Air container 5 is a pressure-stabilizing chamber with a fixed volume, connected in series in the main air path. Its function is to buffer the compressed air output from air pump 6, smoothing airflow pulsations using the chamber volume effect, and providing a stable basic air source for subsequent regulation. The output of air container 5 is connected to the common air path main pipe.

[0037] The pressure regulating actuator includes a booster valve 10, a depressurization valve 11, and a pressure-generating cylinder 8. The booster valve 10 is connected in series between the gas container 5 and the common gas line main pipe, serving as an intake control switch. The booster valve 10 is controlled by an electrical signal to open and close. When the booster valve 10 is open, compressed air from the gas container 5 enters the common gas line, increasing the system pressure; when the booster valve 10 is closed, the gas supply is cut off. One end of the depressurization valve 11 is connected to the common gas line main pipe, and the other end is connected to the exhaust port 21 or directly to the atmosphere. The depressurization valve 11 controls the emission rate of the gas inside the system. By adjusting the opening degree or on / off frequency of the depressurization valve 11, rapid depressurization or linear pressure reduction of the gas line can be achieved.

[0038] To achieve high-precision pressure locking and dynamic compensation, a pressure-generating cylinder 8 is connected in parallel to the air circuit. The pressure-generating cylinder 8 is a variable-volume pressure fine-tuning actuator, containing a piston assembly driven by a motor or linear module. The air port of the pressure-generating cylinder 8 is connected to the common air circuit. When the system is in static pressure maintenance mode, the pressure-generating cylinder 8 slightly alters its internal cavity volume, finely adjusting the pressure within the closed air circuit according to Boyle's Law (PV=nRT) to compensate for pressure fluctuations caused by minor leaks or temperature changes, achieving precise pressure locking. When the system is in dynamic pressure reduction mode, the pressure-generating cylinder 8 works in conjunction with the pressure-reducing valve 11, compensating for the linearity of pressure reduction through controlled piston movement, ensuring the pressure reduction curve meets the set rate requirements.

[0039] In the signal feedback unit, the imported high-precision module 9 and the backup high-precision module 7 are connected in parallel to the common gas line main pipe. The imported high-precision module 9 serves as the main sensor, integrating a pressure-sensitive element to collect the static gauge pressure within the gas line and the weak pulse wave oscillation signal superimposed on the static pressure in real time. The backup high-precision module 7 serves as a redundancy or comparison sensor to monitor the system pressure status. These two modules convert the collected physical pressure signals into analog electrical signals, which are then transmitted to the main board 3 via signal lines.

[0040] The electrical control terminals of the aforementioned air pump 6, pressure cylinder 8, pressure boosting valve 10, and pressure reducing valve 11 are all connected to the driver 2. The driver 2 is electrically connected to the main board 3. The driver 2 receives control commands from the main board 3 and converts the logic level into the power signal required to drive the aforementioned actuators, thereby realizing closed-loop control of the pressure state of the air circuit system.

[0041] See attached document Figure 1 In this embodiment of the invention, the electrical control and drive system constructs the power supply network, signal processing logic, and actuator drive link of the device, realizing automated control from data acquisition to physical action execution.

[0042] The system consists of a power management subsystem, a logic control subsystem, and a power drive subsystem. The power management subsystem uses battery 4 as an independent power source, and the output of battery 4 is electrically connected to the input of power module 12. Power module 12 integrates a voltage regulator circuit and a charging management circuit. Its output is connected to the power input interfaces of motherboard 3 and driver 2 via power cables, providing stable operating voltages for the low-voltage logic circuit and the high-power drive circuit, respectively. Charging port 20 is connected to power module 12 to introduce external power to charge battery 4.

[0043] The logic control subsystem is centered on motherboard 3, which integrates a microprocessor (MCU), memory, and analog-to-digital converter (ADC). The analog signal input ports of motherboard 3 are connected to the signal outputs of the imported high-precision module 9 and the backup high-precision module 7, respectively, to receive analog voltage or current signals transmitted from sensors and convert them into digital pressure data. The communication interfaces of motherboard 3 are connected to the PC communication port 18, USB interface 22, and the data terminal of the LCD screen 14, responsible for processing human-machine interaction commands, displaying graphical data, and parsing external communication protocols. The main switch 19 is connected to the power control circuit of motherboard 3, used for system hardware reset and start / stop control.

[0044] The power drive subsystem mainly consists of driver 2, which converts logic control signals into power drive signals. The control signal input of driver 2 is connected to the GPIO (General Purpose Input / Output) port or PWM (Pulse Width Modulation) output port of motherboard 3. Driver 2 internally contains multiple independent power amplifier circuits or H-bridge drive circuits, whose outputs are electrically connected to the air pump 6 motor, the displacement drive motor inside the pressure cylinder 8, the solenoid coil of the pressure boosting valve 10, and the solenoid coil of the pressure reducing valve 11 in the pneumatic system, respectively. Motherboard 3 sends control levels with preset duty cycles or timings to driver 2 according to its built-in control algorithm. Driver 2 amplifies these levels and drives the aforementioned pneumatic components to precisely control the air pump speed, the displacement of the pressure cylinder piston, and the valve opening and closing frequency and degree.

[0045] See attached document Figure 1 In this embodiment of the invention, high-precision static pressure generation is achieved through a two-stage closed-loop control logic that combines coarse and fine adjustment. This logic mainly relies on the coordinated action of the pressure boosting valve 10 and the pressure generation cylinder 8 in the gas circuit system, and is completed in conjunction with the real-time feedback from the imported high-precision module 9.

[0046] In the initial stage of the static pressure building process, the mainboard 3 first issues a command to control the driver 2 to close the pressure-reducing valve 11, ensuring the airtightness of the air circuit system. Subsequently, the system enters the coarse-adjustment pressure-boosting mode, and the mainboard 3 controls the pressure-boosting valve 10 to open, driving the air pump 6 to start operation. After being compressed by the air pump 6, the outside air first enters the air container 5. After the volume buffer of the air container 5 eliminates airflow pulsation, it is quickly filled into the common air circuit connected to the rotary arm 13 interface through the opened pressure-boosting valve 10. During this period, the imported high-precision module 9 samples the real-time pressure value within the air circuit at a high frequency. And transmit it to motherboard 3. Motherboard 3 will then transmit the real-time stress value. Compared with the preset target static pressure value Comparison calculation. When the real-time pressure value... Approaching the target static pressure value When the target value is within a preset threshold range (e.g., 95% to 98% of the target value), the mainboard 3 immediately sends a command to control the pressure boosting valve 10 to close and stop the air pump 6 from operating, thereby completing the initial inflation of the air circuit.

[0047] After initial inflation, the system immediately switches to fine-tuning servo mode to eliminate pressure drift caused by gas thermodynamic effects and compensate for minor system leaks. In this mode, the mainboard 3 adjusts the pressure deviation based on feedback from the imported high-precision module 9. The required volume compensation is calculated using a built-in PID control algorithm or fuzzy control algorithm. The motherboard 3 controls the rotation direction and step size of the motor inside the pressure cylinder 8 via the driver 2, driving the piston inside the pressure cylinder 8 to perform micron-level axial displacement. When At that time, the piston of the pressure-generating cylinder 8 moves in the compression direction, reducing the total volume of the air passage to increase the pressure; when At this time, the piston moves in the expansion direction, increasing the total volume of the air passage to reduce pressure. Through continuous and minute adjustments of the air passage volume by the pressure-generating cylinder 8, the system can strictly lock the static pressure at the target value. This provides a stable pressure reference environment for subsequent pulse wave amplitude repeatability assessment.

[0048] See attached document Figure 1 In this embodiment of the invention, the linear uniform pressure reduction control strategy is achieved through the coordinated operation of the variable flow resistance adjustment of the pressure reduction valve 11 and the dynamic volume compensation of the pressure-generating cylinder 8. This strategy aims to ensure that the pressure in the gas path system decreases linearly with time, i.e., maintaining the pressure change rate. It is a constant value.

[0049] After entering the buck phase, motherboard 3 determines the target buck rate based on the preset buck level parameters. The motherboard 3 sends a pulse width modulation (PWM) signal or an analog voltage signal to the pressure-reducing valve 11 via the driver 2, controlling the valve to open to its initial opening degree, allowing gas to be discharged through the exhaust port 21. During the exhaust process, as the pressure difference between the inside and outside of the gas path gradually decreases over time, the gas flow rate at a constant valve opening will naturally decrease. To maintain a constant pressure reduction rate, the motherboard 3 periodically calculates the current actual pressure reduction rate based on real-time pressure data fed back by the imported high-precision module 9. .

[0050] Motherboard 3 runs a closed-loop control algorithm, which will and A comparison is performed. Based on the comparison results, the main board 3 adjusts the control signal sent to the pressure reducing valve 11 in real time, gradually increasing the effective opening of the pressure reducing valve 11 as the system pressure decreases to compensate for the flow loss caused by the decrease in pressure difference. At the same time, the pressure building cylinder 8 participates in the control as a linearity correction element. The main board 3 controls the piston in the pressure building cylinder 8 to move at a constant or variable speed according to the small fluctuation of the rate deviation. When a slight increase in the pressure reduction rate is required, the pressure building cylinder 8 performs an expansion movement (the piston is pulled outward); when a slight suppression of the pressure reduction rate is required, the pressure building cylinder 8 performs a contraction movement (the piston is compressed inward). Through the active adjustment of the exhaust flow by the pressure reducing valve 11 and the auxiliary correction of the gas path volume by the pressure building cylinder 8, the device can maintain the linearity of the pressure reduction curve throughout the entire pressure reduction cycle.

[0051] See attached document Figure 1 and appendix Figure 2 In this embodiment of the invention, the experimental preparation and system initialization steps ensure that the calibration operation is started under accurate physical and electrical conditions. This step first establishes a physical pneumatic connection. The operator tightly attaches one end of a pressure-resistant air hose to interface 16 at the end of the rotating arm 13, using the pagoda-shaped barbs on the interface to prevent leakage or detachment. The other end of the hose is then airtightly connected to the test port of the blood pressure simulator to be calibrated, thus connecting the internal pneumatic path of the calibration device with the simulated air chamber of the blood pressure simulator into a closed test system. If an external standard needs to be connected for measurement comparison, a standard pressure gauge is connected to interface 15.

[0052] After establishing the connection, the system is powered on and reset. Pressing the main switch 19 on the back of the main unit 1 powers the system through the power module 12. After powering on and resetting, the main board 3 immediately runs a self-test firmware program, sending a query command to the driver 2 to confirm that the electrical circuits of the air pump 6, pressure cylinder 8, pressure boosting valve 10, and pressure reducing valve 11 are in normal standby mode. Simultaneously, the main board 3 controls the pressure reducing valve 11 to remain fully open, ensuring the common air path is fully connected to the external atmosphere through the exhaust port 21, eliminating residual pressure in the pipeline. Under this normal pressure condition, the main board 3 continuously acquires the output signal from the inlet high-precision module 9, executes the sensor zero-point calibration algorithm, and marks the current detection value as the zero-point reference for the system's relative pressure to eliminate sensor zero-point drift error.

[0053] Finally, the calibration parameters are initialized and configured via the human-machine interface on the LCD screen 14. Based on user input or a preset script, the system loads key control variables required for subsequent steps into memory. These variables include the target pressure value for static stability assessment. Dynamically calibrated initial inflation pressure value (Typically set to be 30 mmHg or more above the systolic pressure of the equipment under test), termination pressure value (Usually set to be 20 mmHg lower than the diastolic pressure of the device under test) and the pressure reduction rate setting parameters.

[0054] See attached document Figure 1 In this embodiment of the invention, the short-time stability assessment of pulse waves under static pressure aims to verify the signal reproduction consistency of the calibrated object at a single operating point. This process is automatically executed by the intelligent control system of the device.

[0055] After the evaluation process is started, motherboard 3 first retrieves the preset static pressure setting value. The motherboard 3 sends a command to the driver 2 to open the pressure boosting valve 10 and start the air pump 6, filling the common air circuit and the connected blood pressure simulator air chamber with gas. When the air circuit pressure detected by the imported high-precision module 9 reaches the set value... At this time, the main board 3 closes the pressure boosting valve 10 and the air pump 6, and then activates the pressure servo control logic of the pressure cylinder 8 to strictly limit the static pressure fluctuation in the system to within the allowable error range, thus creating a constant pressure test environment.

[0056] With the pressure maintained at a constant level, the connected blood pressure simulator senses the external pressure, triggering its internal mechanism to generate a simulated pulse wave signal, which appears as a tiny pressure oscillation superimposed on the static air pressure. The imported high-precision module 9 continuously acquires the mixed pressure signal within the airway at a set sampling frequency and transmits it to the mainboard 3. The mainboard 3, through its built-in digital signal processing algorithm, identifies and extracts the continuous pulse wave signal from the mixed signal. A complete pulse wave waveform. The system measures the peak and trough values ​​of each pulse wave, calculates the difference between them as the amplitude of that pulse wave, and thus obtains a complete pulse wave waveform. A measurement sequence consisting of pulse amplitude values .

[0057] Based on the above measurement sequence, motherboard 3 executes a short-time repeatability calculation algorithm. First, the system calculates the arithmetic mean of the amplitude values ​​of all pulse waves in the sequence. The calculation formula is as follows: ; In the formula, Indicates the first The amplitude of each pulse wave, This indicates the total number of pulse waves collected.

[0058] Next, the system calculates the experimental standard deviation of the amplitude sequence. The calculation formula is as follows: ; Finally, the system calculates the relative repeatability of the pulse wave amplitude. The calculation formula is as follows: ; After the calculation is completed, motherboard 3 will obtain The value is compared with a system-preset threshold (e.g., 5%) to determine the result. If the signal is less than or equal to a preset threshold, the motherboard 3 determines that the current signal generation status of the blood pressure simulator is stable and automatically jumps to the subsequent dynamic calibration program; if... If the signal exceeds the preset threshold, the mainboard 3 determines that the signal stability is insufficient, issues a warning message through the LCD screen 14, and terminates the calibration process to prevent the unstable signal source from affecting the accuracy of subsequent blood pressure reading repeatability measurements.

[0059] See attached document Figure 1 In this embodiment of the invention, the full envelope acquisition step during the dynamic blood pressure reduction process is the core step in obtaining the characteristic data of the blood pressure simulator oscillometric method. This step simulates the physical process of inflation and deflation of the human cuff through the device, which stimulates the blood pressure simulator to generate a complete pulse wave sequence and record it synchronously.

[0060] This step begins with the pressurization and inflation phase. According to preset control logic, the mainboard 3 first sends a command to the driver 2 to open the pressure-boosting valve 10 and close the pressure-reducing valve 11, simultaneously driving the air pump 6 to operate at full speed. External air is pumped into the common air path, and the pressure within the air path rises rapidly. To ensure the acquisition of a complete pulse wave envelope curve, especially the rising edge of the envelope, the mainboard 3 continuously monitors the pressure value fed back by the inlet high-precision module 9 until the air path pressure reaches the preset initial pressure value. This initial pressure value It is set to a value higher than the systolic blood pressure setting of the blood pressure simulator to be measured (e.g., 30 mmHg to 40 mmHg higher than the systolic blood pressure) to ensure sufficient pressure stabilization margin before the effective measurement range.

[0061] When the air pressure reaches Then, the system automatically switches to the uniform linear depressurization phase. Mainboard 3 closes the booster valve 10 and air pump 6, and controls the depressurization valve 11 to open for exhaust via driver 2. During this process, mainboard 3 calls the linear depressurization control subroutine, dynamically adjusting the opening of the depressurization valve 11 and the compensation displacement of the pressure-generating cylinder 8 according to the set depressurization rate (e.g., 3 mmHq / s), so that the static pressure in the airway decreases linearly at a constant rate. At this time, the pressure sensor inside the blood pressure simulator connected to the airway senses this linearly decreasing pressure signal and, based on its internal preset physiological model, triggers the generation of a simulated pulse wave signal at a preset pressure point. This simulated pulse wave signal appears as a series of weak pressure pulsations superimposed on the linearly decreasing static pressure baseline.

[0062] Throughout the depressurization process, the device performs high-frequency synchronous data acquisition. The imported high-precision module 9 continuously captures the composite pressure signal within the gas path at a set high sampling rate (e.g., 100Hz or higher). The digital signal processing unit within the mainboard 3 receives this signal in real time and processes it: firstly, it filters out high-frequency pulsating components using a low-pass filtering algorithm to extract the real-time static pressure value at each moment. On the other hand, by using high-pass or band-pass filtering algorithms to filter out the slowly changing static pressure baseline, the superimposed pulse wave oscillation signal at each moment is extracted, and the peak-to-peak value of the oscillation signal is calculated as the pulse wave amplitude. .

[0063] Motherboard 3 will extract the static pressure value at the same time. With pulse amplitude The data is associated and bound, and stored in high-speed memory in chronological order. Data acquisition continues until the gas pressure drops below the preset termination pressure. (This value is set below the diastolic blood pressure setting of the blood pressure simulator to be measured), ensuring that the system completely records all pulse wave data from the systolic to diastolic zone, forming a complete dataset containing the rising edge, peak area, and falling edge of the pulse wave envelope. ,in This represents the total number of data points collected. This full envelope dataset provides the initial data foundation for accurately locating the actual mean pressure.

[0064] See attached document Figure 5In this embodiment of the invention, the feature extraction and actual mean pressure (MAP) localization steps are performed by the computing unit inside the motherboard 3. The purpose is to reconstruct continuous physiological signal features from discrete sampled data through mathematical means, thereby accurately locking the physical mean pressure position of the device under test in this measurement.

[0065] This step first processes the dataset recorded in the memory from the previous stage. Reorganization is performed. Motherboard 3 removes time-dimensional variables and constructs a system based on static stress values. The graph shows the distribution of discrete points with the corresponding pulse wave amplitude (Amp) on the y-axis. Because the original sampled data is limited by the sampling rate and airflow disturbances, it typically appears as discrete scatter points with random noise. Directly selecting the maximum sampled value as the peak value results in significant error. Therefore, this embodiment employs a numerical fitting algorithm to construct a pulse wave oscillation envelope model.

[0066] Mainboard 3 uses the least squares method to perform high-order polynomial fitting on discrete data points, generating a continuous envelope curve function that can describe the trend of pulse wave amplitude changing with static pressure. To balance computational efficiency with the smoothness of curve fitting, the fitting function is typically a fourth- or sixth-order polynomial in the following form: ; In the formula, This represents the fitted pulse wave amplitude. Represents static pressure. These are the polynomial coefficients calculated using the least squares regression method. The order of the polynomial (preferred in this embodiment) Up to 6).

[0067] Constructing a continuous envelope curve function Then, the system executes an extreme value search algorithm to locate the actual mean pressure. According to the principle of oscillometric blood pressure measurement, the static pressure corresponding to the moment when the pulse wave oscillation amplitude is largest is the mean arterial pressure. Therefore, the mainboard 3 pairs the fitting function... About stress Find the first derivative and set it to zero to establish the following equation: ; Motherboard 3 uses numerical methods (such as Newton's iteration method) to solve the above equations within the measured pressure range. The system determines the real roots within the range. The system performs second-order derivative determination on the solved roots (i.e., ...). This is used to filter out the maximum points of the function. The static pressure value corresponding to this maximum point. This is determined to be the actual average pressure during this dynamic measurement process, denoted as... Through the above mathematical processing, the device can accurately capture the peak position between sampling points, and its resolution is not limited by the sampling interval of the original data, thus achieving high-precision positioning based on actual averaging.

[0068] See attached document Figure 6 In this embodiment of the invention, after the location of the single actual average pressure is completed, the device does not immediately output a conclusion. Instead, the main board 3 starts a statistical analysis program to quantify the repeatability of the tested device through statistical processing of multiple sample data.

[0069] To ensure statistical significance of the evaluation results and eliminate the influence of random errors from single measurements, the system is programmed to automatically execute multiple independent measurement cycles. Motherboard 3 sets the repeat measurement counter. (In this embodiment, it is set) ), and control the gas circuit system to continuously execute This involves a complete sequence of inflation, depressurization, and data acquisition. In each cycle, the gas system is completely depressurized to zero before being re-inflated to ensure the independence of each measurement. After each cycle, the system calculates a corresponding actual average pressure value based on the aforementioned feature extraction algorithm. The value is then stored sequentially in the data queue of the internal volatile memory. When the counter reaches a preset value... At that time, a set containing data was formed in the data queue. A sequence of independent measurement results .

[0070] Motherboard 3 then performs statistical operations on the sequence. First, it calculates the arithmetic mean of the sequence. As an estimate of the central tendency of the tested equipment under this operating condition, the calculation formula is as follows: ; In the formula, For the first The actual average pressure value obtained from this measurement. To measure the total number of times.

[0071] Subsequently, motherboard 3 uses Bessel's formula to calculate the experimental standard deviation of the measurement sequence, and defines this standard deviation as the repeatability of the blood pressure readings of the blood pressure simulator being measured. The calculation formula is as follows: ; This indicator The pressure unit (mmHg) directly characterizes the consistency of the blood pressure simulator in reproducing oscillometric feature points during dynamic blood pressure reduction; a smaller value indicates better repeatability. Motherboard 3 will calculate the... The numerical values ​​are rounded to two decimal places and displayed directly to the operator on the LCD screen 14. Furthermore, if the system has preset pass / fail thresholds required by metrological technical specifications (e.g., ...), ... (mmHg), the motherboard 3 will also automatically execute comparison logic, compare the calculation result with the threshold, and simultaneously display the qualified or unqualified judgment label on the screen, thus completing the fully automated calibration process from data acquisition to the generation of measurement conclusions.

[0072] Specific application examples: Based on the aforementioned hardware architecture and control logic, a specific application example is constructed below to demonstrate the effectiveness of the present invention in solving technical problems.

[0073] Subject of implementation: A certain model of high-end non-invasive blood pressure simulator (setting parameters: systolic blood pressure 120mmHg, diastolic blood pressure 80mmHg, heart rate 60bpm, pulse wave volume 1.0ml).

[0074] Implementation steps: System connection: Connect the calibration device's interface 2 16 to the blood pressure simulator to be measured via a rigid PU tube.

[0075] Parameter configuration: Set on LCD screen 14: Static stability evaluation points: =150mmHg.

[0076] Dynamic blood pressure reduction range: =160mmHg to =60 mmHg.

[0077] Target pressure reduction rate: 3.0 mmHg / s.

[0078] Static pre-check: Start-up device. Air pump 6 inflates to 150 mmHq, pressure boosting valve 10 closes. Pressure cylinder 8 engages, fine-tuning the air path volume with a 20ms adjustment cycle. Imported high-precision module 9 continuously monitors for 30 seconds, measuring the relative repeatability of pulse wave amplitude. =1.2% (threshold 5%), deemed acceptable.

[0079] Dynamic data acquisition: The system is inflated to 160 mmHg. Pressure reduction valve 11 opens for coarse venting, while the piston of pressure cylinder 8 adjusts according to the real-time pressure drop rate deviation. Perform linear compensation motion (pull outward to increase the rate of pressure reduction, or compress inward to slow down the rate of pressure reduction).

[0080] Data processing: Motherboard 3 records the entire process data, and through fourth-order polynomial fitting, the actual average pressure of this measurement is located. = 98.45 mmHg.

[0081] Repeatability of output: Execute the above loop 10 times consecutively to calculate the repeatability of the displayed value. =0.18mmHg, which is far better than the measurement specification requirement of 0.50mmHg, indicating that the equipment is in excellent condition.

[0082] To verify the superiority of the gas path volume dynamic compensation (pressure cylinder 8 and pressure reducing valve 11) technology in this invention over the traditional single proportional valve control, we conducted a comparative experiment under the same environmental conditions.

[0083] Experimental setup: Experimental group (the present invention scheme): The volume servo function of the pressure cylinder 8 is activated, and linear pressure reduction is performed in conjunction with the pressure reducing valve 11.

[0084] Control group (traditional scheme): The pressure-generating cylinder 8 is disabled, and pressure reduction is achieved solely by adjusting the PWM duty cycle of the pressure-reducing valve 11 for open-loop or simple PID closed-loop pressure reduction.

[0085] Test objective: Target blood pressure reduction rate of 3.0 mmHg / s, from 160 mmHg to 60 mmHg.

[0086] Comparison metrics: linearity ( ): Evaluate the degree of fit between the pressure drop curve and the ideal straight line.

[0087] Rate fluctuation: The range of instantaneous rate fluctuations during the voltage reduction process.

[0088] Indication repeatability : Statistical standard deviation of 10 measurements.

[0089] Analysis of experimental results: See attached document Figure 8 In the control group: because the gas flow rate naturally decreases as the pressure difference decreases, it is difficult for a single valve to maintain a constant flow rate in the low-pressure range (<80mmHg), resulting in the pressure drop curve showing an obvious exponential decay characteristic (downward convexity). =0.924.

[0090] This nonlinearity causes the time window for the simulator to identify pulse waves to be inconsistent at different pressure levels, introducing measurement errors.

[0091] Experimental group: Because the pressure-generating cylinder 8 actively expands outward when the pressure difference decreases, it compensates for the flow rate loss, resulting in a strictly linear decrease in pressure over time throughout the entire process. =0.999.

[0092] See attached document Figure 9 and attached Figure 10The figure shows the pulse wave envelope fitting curves extracted from 10 measurements. The 10 curves of the experimental group almost completely overlap, and the calculated values ​​are... =0.18 mmHg; while the control group, due to the characteristic point drift caused by the nonlinearity of the blood pressure reduction, had a more discrete curve distribution. =0.65mmHgo This invention solves the nonlinear problem in the gas depressurization process through micro-volume servo innovation in hardware architecture, improves the stability of actual average pressure positioning, and enables the calibration device to meet and exceed the requirements of high-level metrology standards.

Claims

1. A method for calibrating the repeatability of a blood pressure simulator, characterized in that, Includes the following steps: The motherboard (3) controls the air pump (6) and the pressure boosting valve (10) to pressurize the common air circuit through the driver (2), and uses the micro-volume adjustment function of the pressure cylinder (8) to lock the pressure in the air circuit at the preset target static pressure. The imported high-precision module (9) collects the pulse wave data generated by the blood pressure simulator and evaluates the signal stability under static pressure. After the signal stability meets the preset conditions, the common air passage is controlled to be filled with air to a starting pressure higher than the systolic pressure. Through the opening adjustment of the pressure reducing valve (11) and the volume dynamic compensation of the pressure building cylinder (8), the pressure in the common air passage is linearly and uniformly reduced at a set rate. During this process, full envelope data including real-time static pressure value and pulse wave amplitude value are collected simultaneously. The full envelope data is processed using a numerical fitting algorithm to construct an envelope model of pulse wave amplitude variation with static pressure, and the actual mean pressure of this measurement is located based on the envelope model. The common airway is refilled to the initial pressure, and the linear uniform descent and actual average pressure positioning steps are repeated multiple times. The experimental standard deviation of the multiple actual average pressure values ​​is calculated, and the experimental standard deviation is used as the repeatability result of the blood pressure simulator.

2. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, The step of using the micro-volume adjustment function of the pressure-generating cylinder (8) to lock the pressure in the air circuit at the preset target static pressure specifically includes: After the air pressure approaches the target static pressure and the air pump (6) stops running, the main board (3) calculates the volume compensation amount using PID control algorithm or fuzzy control algorithm based on the deviation between the real-time pressure value fed back by the imported high-precision module (9) and the target static pressure. When the real-time pressure value is less than the target static pressure, the piston in the pressure cylinder (8) is controlled to move in the compression direction to reduce the total volume of the air passage; When the real-time pressure value is greater than the target static pressure, the piston is controlled to move in the expansion direction to increase the total volume of the air passage, thereby maintaining the static pressure at the target value.

3. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, The steps for evaluating signal stability under static pressure specifically include: Extract multiple consecutive complete pulse wave waveforms, measure the difference between the peak value and the trough value of each pulse wave waveform as the pulse wave amplitude, and obtain a measurement sequence; Calculate the arithmetic mean of all pulse wave amplitudes in the measurement sequence; Calculate the experimental standard deviation of the measurement sequence; The ratio of the experimental standard deviation to the arithmetic mean is calculated as relative repeatability; The relative repeatability is compared with a preset threshold. If the relative repeatability is less than or equal to the preset threshold, the signal stability is determined to meet the preset condition.

4. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, The steps involving the coordinated action of adjusting the opening of the pressure reducing valve (11) and the dynamic volume compensation of the pressure-generating cylinder (8) specifically include: The mainboard (3) determines the target voltage reduction rate according to the preset voltage reduction gear parameters and controls the voltage reduction valve (11) to open for exhaust. The actual pressure drop rate of the gas path is calculated periodically, and the actual pressure drop rate is compared with the target pressure drop rate. Adjust the effective opening of the pressure reducing valve (11) and compensate for flow loss based on the comparison results; Simultaneously, the piston movement within the pressure cylinder (8) is controlled based on the rate deviation: When it is necessary to increase the depressurization rate, the pressure cylinder (8) is controlled to perform an expansion movement; when it is necessary to suppress the depressurization rate, the pressure cylinder (8) is controlled to perform a contraction movement to maintain a constant pressure change rate.

5. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, The steps for synchronously acquiring full envelope data including real-time static pressure values ​​and pulse amplitude values ​​specifically include: The imported high-precision module (9) is used to continuously capture the composite pressure signal in the gas path with a high sampling rate; A low-pass filtering algorithm is used to filter out high-frequency pulsating components from the composite pressure signal and extract the real-time static pressure value at each moment. The static pressure baseline is filtered out from the composite pressure signal using a high-pass or band-pass filtering algorithm. The pulse wave oscillation signal at each moment is extracted and the peak-to-peak value of the pulse wave oscillation signal is calculated as the pulse wave amplitude. The real-time static pressure value and pulse amplitude value at the same moment are associated, bound, and stored until the gas pressure drops below the preset termination pressure value.

6. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, The step of processing the full envelope data using a numerical fitting algorithm and locating the actual mean pressure of this measurement based on the envelope model specifically includes: Remove the time dimension variable from the full envelope data and construct a discrete point set with static pressure value on the x-axis and pulse amplitude value on the y-axis; The discrete point set is fitted with a high-order polynomial using the least squares method to generate a continuous envelope curve function. The first derivative of the envelope curve function with respect to pressure is calculated, and the roots with zero derivative are solved using a numerical method. The roots obtained are subjected to second derivative determination to screen out the maximum points, and the static pressure value corresponding to the maximum point is determined as the actual average pressure.

7. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, The specific steps involved in calculating the experimental standard deviation of the multiple actual average pressure values ​​include: After each cycle of measurement, the calculated actual average pressure value is stored in the data queue; When the number of cyclic measurements reaches a preset value, calculate the arithmetic mean of all actual average pressure values ​​in the data queue; The sum of squares of the deviations of each actual average pressure value in the data queue from the arithmetic mean is calculated using the Bessel formula; The experimental standard deviation is obtained by calculating the sum of squared deviations and dividing it by the square root of the number of measurements minus one.

8. The method for repeatability calibration of a blood pressure simulator according to claim 1, characterized in that, Before controlling the air pump (6) and the booster valve (10) to charge the common air circuit, an initialization step is also included: The pressure reducing valve (11) is kept fully open, so that the common gas path is connected to the outside atmosphere through the exhaust port (21); The output signal of the imported high-precision module (9) is continuously collected under normal pressure, and the sensor zero-point calibration algorithm is executed to mark the current detection value as the zero-point reference of the system relative pressure.

9. A blood pressure simulator repeatability calibration device, used to perform the blood pressure simulator repeatability calibration method according to any one of claims 1-8, characterized in that, include: The main unit (1) has a handle (17) on its top, an LCD screen (14) and a USB interface (22) on its front side, a PC communication port (18), a main switch (19) and a charging port (20) on its back side, an exhaust port (21) and a rotating arm (13) for connecting to the blood pressure simulator to be calibrated on its side, and an interface one (15) and an interface two (16) on the rotating arm (13). The motherboard (3) and driver (2) are located inside the host (1) and electrically connected. The host (1) is also equipped with a battery (4) and a power module (12). The power module (12) is connected to the charging port (20) and supplies power to the motherboard (3) and driver (2). The gas system is located inside the host (1) and includes an air pump (6), an air container (5) and a pressure booster valve (10) connected in sequence. The output end of the pressure booster valve (10) is connected to a common gas path, and the common gas path is connected to the interface one (15) and the interface two (16). The gas circuit system also includes a pressure reducing valve (11), a pressure generating cylinder (8), an inlet high-precision module (9), and a spare high-precision module (7) connected in parallel to the common gas circuit. The electrical control terminals of the air pump (6), the pressure boosting valve (10), the pressure reducing valve (11) and the pressure generating cylinder (8) are respectively connected to the driver (2), the signal output terminals of the inlet high-precision module (9) and the spare high-precision module (7) are connected to the main board (3), and the exhaust terminal of the pressure reducing valve (11) is connected to the exhaust port (21).

10. A blood pressure simulator repeatability calibration device according to claim 9, characterized in that, The pressure cylinder (8) is a variable volume pressure fine-tuning actuator, which contains a piston assembly driven by a motor. The mainboard (3) is used to send instructions to the driver (2) to control the pressure cylinder (8) to compensate for pressure fluctuations by piston displacement in static pressure maintenance mode, and to correct the linearity of the pressure drop rate by uniform or variable speed movement of the piston in dynamic pressure reduction mode.

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