Piston type simulation lung capable of accurately controlling compliance

Abstract

The utility model discloses a piston type simulation lung capable of accurately controlling compliance, which comprises a stepping motor, a piston head, a first rod and a second rod, and is characterized by further comprising a piston cylindrical cavity, a screw rod, an air inlet, a pressure sensor, a temperature sensor, a humidity sensor and a control assembly, the piston cylindrical cavity is of a sealed cylindrical structure, and an air inlet is formed in the axial direction of the piston cylindrical cavity; the air inlet is provided with a pressure sensor, a temperature sensor and a humidity sensor, and the pressure sensor, the temperature sensor and the humidity sensor are connected with the control assembly; the control assembly is connected with the stepping motor; a piston head is arranged in the cylindrical cavity of the piston and fixedly connected with a second rod, and the end, away from the piston head, of the second rod is perpendicularly connected with the first rod; one end of the first rod is connected with the lead screw in a matched mode, and the lead screw is connected with the stepping motor in a matched mode and used for piston movement. Precise control and simulation of the lung can be realized, and the system is suitable for various treatment and training environments.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of biomedical engineering, concretely relates to a simulation lung of accurate control compliance. BACKGROUND

[0002] The simulation lung refers to a simulation device designed according to the breathing movement mode of the real human lung system. The simulation lung is not an anatomical model of the real human body; the simulation lung simulates the compliance and airway resistance of the lung in the normal physiological or pathological state, and is an indispensable powerful tool for clinical medical teaching, training and scientific research, and is also an essential instrument for accurately detecting various performance indicators of a breathing machine.

[0003] The breathing machine manufacturers use simulation lung experiments to evaluate and optimize the performance and functions of the breathing machines they produce. The simulation lung should be able to simulate the physiological characteristics of the human lung, including gas transmission, oxygenation capacity, pressure regulation and other functions, according to the experimental data to evaluate the performance of the breathing machine. Analyze the gas transmission efficiency, oxygenation capacity, pressure regulation accuracy and other indicators to evaluate whether the performance of the breathing machine meets the design requirements. By using simulation lung experiments, breathing machine manufacturers can better understand the performance characteristics of the breathing machines they produce, find problems and improve them, thereby improving the quality and performance of the breathing machines and providing better treatment experience for medical institutions and patients. In addition, the simulation lung can also be used to train medical staff to use the breathing machine, improve their operation skills and ability to respond to emergencies. By simulating the real respiratory system, medical staff can conduct combat exercises in a simulated environment to improve their ability to respond to problems that may arise during the use of the breathing machine. In general, the application of bionic simulation lung in breathing machine helps to improve the performance and reliability of the breathing machine, and also provides better training and practice opportunities for medical staff, thereby improving the effectiveness and safety of the breathing machine in clinical treatment. The existing simulation lung generally uses a soft air bag to simulate the human lung, which has the problems of high difficulty in obtaining compliance data, unstable operation of the simulation device, high difficulty, and inability to accurately control lung activity and wear caused by tremor. UTILITY MODEL CONTENTS

[0004] In order to solve the problems of high difficulty in obtaining compliance data, unstable operation of the simulation device, high difficulty, and inability to accurately control lung activity and wear caused by tremor of the soft air bag simulation lung in the prior art, the piston type simulation lung provided by the utility model can realize accurate control and simulation of the lung, can simulate different breathing modes, can obtain related data of compliance, and can be used to meet different training and treatment needs.

[0005] A piston type simulation lung with precise compliance control, comprising a stepping motor, a piston head, a first rod, a second rod, characterized in that it further comprises a piston cylinder cavity, a lead screw, an air inlet, a pressure sensor, a temperature sensor, a humidity sensor and a control assembly;

[0006] The piston cylinder cavity is a sealed cylindrical structure, and the air inlet is arranged in the axial direction of the piston cylinder cavity; the air inlet is provided with a pressure sensor, a temperature sensor and a humidity sensor, and the pressure sensor, the temperature sensor and the humidity sensor are connected with the control assembly; the control assembly is connected with the stepping motor; the piston head is arranged in the piston cylinder cavity, the piston head is fixedly connected with the second rod, and the end of the second rod away from the piston head is connected with the first rod perpendicularly; one end of the first rod is connected with the lead screw in a matching mode, and the lead screw is connected with the stepping motor in a matching mode, so as to realize piston movement.

[0007] Preferably, the surface of the piston head in contact with the piston cylinder cavity is provided with a sealing groove, which is matched with the piston cylinder cavity to achieve a sealing effect.

[0008] Preferably, the surface of the lead screw is provided with a protective layer.

[0009] Preferably, the surface of the lead screw is provided with a multi-start thread, which converts the rotary motion of the lead screw into the linear motion of the first rod.

[0010] Preferably, the other end of the first rod is fixedly connected with a guide rod.

[0011] Preferably, the surface of the lead screw is provided with a protective layer.

[0012] Preferably, the inside of the air inlet is provided with a heating assembly.

[0013] Preferably, the control assembly comprises a PC and a hard disk, so as to realize the switching of the stepping motor and the data storage of the pressure sensor, the temperature sensor and the humidity sensor.

[0014] Preferably, the surface of the guide rod is provided with a protective layer.

[0015] Preferably, the inside of the guide rod is provided with a shock absorber.

[0016] Compared with the prior art, the piston type simulation lung device has the following technical effects:

[0017] (1) The piston type simulation lung device can realize precise simulation and simulate different breathing modes, such as controlled ventilation, assisted ventilation and pressure support ventilation, and the shock absorber arranged on the guide rod can reduce the abrasion caused by the piston movement, and the operation is simple.

[0018] (2) The piston-type simulated lung device provided by this utility model can obtain data such as pressure, temperature and humidity of the simulated lung, provide accurate data for compliance calculation, and meet different training and treatment needs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the piston-type simulated lung in Embodiment 1 of this utility model;

[0020] Figure 2 This is a circuit diagram of the control component of Embodiment 1 of this utility model;

[0021] Figure 3 This is a circuit diagram of the control component of Embodiment 1 of this utility model;

[0022] Figure 4 This is a circuit diagram of the control component of Embodiment 1 of this utility model;

[0023] Figure 5 This is the encoder circuit diagram of the control component in Embodiment 1 of this utility model.

[0024] In the picture:

[0025] 1. Piston cylindrical cavity; 2. Lead screw; 3. Pressure sensor; 4. Air inlet; 5. Piston head; 6. Guide rod; 7. First rod; 8. Stepper motor; 9. Control components; 10. Second rod. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Unless otherwise defined, the technical or scientific terms used in this disclosure should have the ordinary meaning understood by those skilled in the art to which this disclosure pertains. The terms "comprising" or "including," and similar words used in this disclosure, mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] The following is in conjunction with the appendix Figures 1-5 The present invention will be further described with reference to Example 1:

[0028] like Figure 1 As shown,

[0029] The application discloses a piston type simulation lung with precise compliance control, which comprises a stepping motor 8, a piston head 5, a first rod 7, a second rod 10, a piston cylinder cavity 1, a screw rod 2, an air inlet 4, a guide rod 6, a pressure sensor 3, a temperature sensor (not shown in the figure), a humidity sensor (not shown in the figure) and a control assembly 9. The piston cylinder cavity 1 is a sealed cylindrical structure, the air inlet 4 is arranged on the axial direction of the piston cylinder cavity 1, and the outside of the air inlet 4 is provided with the pressure sensor 3, the temperature sensor (not shown in the figure) and the humidity sensor (not shown in the figure) for monitoring the changes of the pressure, the temperature and the humidity in the cavity. The surface of the air inlet 4 away from the piston head 5 is provided with a detachable filter screen (not shown in the figure) for simulating a real respiratory system. The inside of the air inlet 4 is provided with a heating assembly (not shown in the figure) for providing a constant temperature environment. The pressure sensor 3, the temperature sensor (not shown in the figure) and the humidity sensor (not shown in the figure) are connected with the control assembly 9, the control assembly 9 comprises a PC (not shown in the figure) and a hard disk (not shown in the figure) for controlling the switching of the stepping motor 8 and storing the data of the pressure, the temperature and the humidity. The piston head 5 is arranged in the piston cylinder cavity 1, the piston head 5 is fixedly connected with the second rod 10, the end of the second rod 10 away from the piston head 5 is perpendicularly connected with the first rod 7, then one end of the first rod 7 is connected with the screw rod 2 in a matched mode, and the rotational movement of the screw rod 2 is converted into the linear movement of the first rod 7. The screw rod 2 is connected with the stepping motor 8 in a matched mode, is used for driving the first rod 7 and the second rod 10 to move, realizes the piston movement, and is fixedly connected with the guide rod 6 at the other end, so that the first rod 7 and the second rod 10 can move stably and keep the correct moving direction. The outer surface of the guide rod 6 is provided with a protective layer (not shown in the figure) for preventing corrosion, and the inner portion of the guide rod 6 is provided with a shock absorber (not shown in the figure) for reducing the loss caused by the vibration.

[0030] The surface of the screw rod 2 is provided with a multi-start thread and a protective layer (not shown in the figure), and the protective layer is made of nickel and is used for preventing corrosion and the loss caused by friction. The surface of the piston head 5, which is in contact with the piston cylinder cavity 1, is provided with a sealing groove (not shown in the figure) for use in cooperation with the piston cylinder cavity 1 to achieve the sealing effect. Since the simulation lung effect is required, the pressure sensor 3, the temperature sensor (not shown in the figure) and the humidity sensor (not shown in the figure) are all made of polytetrafluoroethylene as the material to provide good corrosion resistance.

[0031] The working principle of the control assembly 9 is shown in the circuit diagram as Figures 2-5 Figure 2 Figure 2 ​​The medium pressure sensor is 24V power supply, (4-20) mA analog current signal output, pressure range ±18kPa, the maximum allowable error is 0.1kPa; the sensor output current signal is connected to the analog-to-digital converter AD7124 through the sampling resistor R1, and then the microprocessor STM32F429 communicates with the analog-to-digital converter through the SPI (CS / DIN / SCLK / DOUT) bus, so as to obtain the pressure value of the pressure sensor; wherein the temperature measurement adopts platinum resistance as the sensor, in order to improve the temperature measurement accuracy of the platinum resistance sensor, the high resolution characteristics of the delta-sigma analog-to-digital converter AD7124 are utilized, and the proportional source elimination circuit is combined to eliminate the problem of platinum resistance output voltage signal fluctuation caused by unstable excitation source. The platinum resistance signal processing method of the proportional source elimination circuit is shown in the following figure, the analog signal inlet of AD7124 is further improved in signal stability by using a π-type filter network, and the maximum allowable error of the measurement result is less than ±0.03℃, and the annual stability is better than ±0.05℃.

[0032] Figure 3 As can be known, the differential signal output by ADS1274 through R2 / R3 can collect the voltage V1 across the platinum resistance, the differential signal output by R4 / R6 can obtain the voltage V2 across the reference resistance, and the voltage coding value X of the platinum resistance can be obtained by using formula 1.

[0033] The voltage coding value X of the platinum resistance can be obtained by using formula 1. REF Vref is the reference voltage of ADS1274 chip.

[0034]

[0035] The voltage coding value X of the sampling resistor can be obtained by using formula 2.

[0036]

[0037] X PT100 and A fixed value X C ,

[0038]

[0039] V1, V2 are both flowed by the same loop circuit, and R5 is 5100Ω, so,

[0040] R PT100 =X c ×R5=5100X c

[0041] The microprocessor calculates X CThe value of R5 can be obtained, and only one variable of R5 exists, the precision is very high, and finally the temperature value is accurately calculated by inquiring the resistance scale of the platinum resistance. The motor driving part adopts a servo driver and an encoder cooperation mode to realize high-precision positioning. The circuit of the driver is shown in the lower part of the figure. The microprocessor is connected to the pins of the driver through an optical coupling isolation mode, DJ1 and DJ2 control the pulse quantity and the rotation direction to determine the movement speed and direction, and DJ3 is a driving enable pin.

[0042] According to Figure 5 It can be known that the differential signals (A+ / A-, B+ / B-) of the incremental photoelectric encoder need to be sent into the differential receiver AM26LS32 to convert them into single-ended signals (A, B) after passing through the inlet ESD protection, π-type filtering and common-mode rejection filter, so as to eliminate common-mode noise and enhance the anti-interference ability. In order to strengthen the anti-noise interference of the system, a high-speed isolation chip ADuM1200 can be added to realize electrical isolation and protect the MCU side circuit, and an independent power supply needs to be configured for the isolation region. After the signal is isolated, it is finally connected to the timer encoder interface TIM1_CH1 / CH2 channel of the MCU. The MCU automatically captures the phase relationship of the A / B phase through the quadrature decoding mode: when the rising edge of the A phase appears, if the B phase is low, it is determined as clockwise rotation, and if it is high, it is counterclockwise. Combined with the increment and decrement counting of the timer, the high-precision detection of the direction and position is realized. This process takes into account signal integrity, anti-interference and level matching, and is widely used in servo control, robot motion detection and other scenes.

[0043] According to Figure 5 It can be known that the specific use process is that the microprocessor takes the target compliance set by the user (C_target) as the input, and calculates the current compliance (C_current) based on the real-time pressure signal. The specific process is as follows:

[0044] The pressure sensor collects the cavity pressure in real time;

[0045] The collected environmental parameters correct the pressure;

[0046] Temperature correction: according to the ideal gas state equation (PV=nRT), the pressure value is linearly compensated by using the temperature sensor data, and the correction formula is:

[0047]

[0048] Where, T 标准 is the reference temperature (such as 25℃).

[0049] Humidity correction: the relative humidity (RH) is obtained through the humidity sensor, and the water vapor partial pressure (P H2O ) is calculated by combining the saturated water vapor pressure table, and the humidity influence is deducted from the total pressure:

[0050] P 干气 =P 修正 -PH2O

[0051] Volume-pressure feedback control

[0052] According to the corrected pressure value (P 干气 ) and the target compliance, the target volume change amount ΔV_target=C_target×ΔP 干气 ) is back calculated.

[0053] The stepper motor speed and steering are adjusted by the PID algorithm to control the displacement amount of the lead screw 2, dynamically adjust the piston position to change the cavity volume (ΔV), until the measured compliance (C_current) and the set value error tend to zero. The device can adapt to different breathing modes (such as spontaneous breathing, mechanical ventilation), and is suitable for calibration of respiratory treatment equipment, medical training, and lung function research in multiple scenes.

[0054] The multi-start thread provided by the lead screw 2 can convert rotary motion into linear motion of the piston, the guide rod 6 can make the simulation lung device stably move the piston, the shock absorber (not shown in the figure) provided by the guide rod 6 can reduce equipment wear caused by linear motion of the piston; the detachable filter screen (not shown in the figure) of the air inlet 4 can accurately simulate the breathing condition, the pressure sensor 3, the temperature sensor (not shown in the figure) and the humidity sensor (not shown in the figure) provided by the air inlet 4 can obtain the pressure, temperature and humidity data in the piston cylindrical cavity 1, and can provide accurate data support for subsequent lung compliance calculation, and the simulation lung device provided by the utility model can also be suitable for various treatment and training scenes.

Claims

1. A piston-type simulated lung with precise control of compliance, comprising a stepper motor (8), a piston head (5), a first rod (7), and a second rod (10), characterized in that, It also includes a piston cylindrical cavity (1), a lead screw (2), an air inlet (4), a pressure sensor (3), a temperature sensor, a humidity sensor, and a control component (9); The piston cylindrical cavity (1) is a sealed cylindrical structure, and an air inlet (4) is provided in the axial direction of the piston cylindrical cavity (1); The air inlet (4) is provided with a pressure sensor (3), a temperature sensor, and a humidity sensor, and the pressure sensor (3), the temperature sensor, and the humidity sensor are connected to the control component (9); The control component (9) is connected to the stepper motor (8); A piston head (5) is provided inside the piston cylindrical cavity (1), and the piston head (5) is fixedly connected to the second rod (10), and the end of the second rod (10) away from the piston head (5) is perpendicularly connected to the first rod (7); One end of the first rod (7) is connected to the lead screw (2), and the lead screw (2) is connected to the stepper motor (8) for piston movement.

2. The piston-type simulated lung with precise compliance control according to claim 1, characterized in that, The piston head (5) has a sealing groove on the surface that contacts the piston cylindrical cavity (1), which works in conjunction with the piston cylindrical cavity (1) to achieve a sealing effect.

3. A piston-type simulated lung with precise compliance control according to claim 1, characterized in that, The surface of the lead screw (2) is provided with a protective layer.

4. A piston-type simulated lung with precise compliance control according to claim 1, characterized in that, The surface of the lead screw (2) is provided with multi-threaded threads, which convert the rotational motion of the lead screw (2) into the linear motion of the first rod (7).

5. A piston-type simulated lung with precise compliance control according to claim 1, characterized in that, The other end of the first rod (7) is fixedly connected to the guide rod (6).

6. A piston-type simulated lung with precise compliance control according to claim 1, characterized in that, The air inlet (4) is provided with a removable filter screen on the side away from the piston head (5).

7. A piston-type simulated lung with precise compliance control according to claim 1, characterized in that, A heating element is provided on the inner side of the air inlet (4).

8. A piston-type simulated lung with precise compliance control according to claim 1, characterized in that, The control component (9) includes a PC and a hard disk, which enables the switching of the stepper motor (8) and the storage of data for the pressure sensor (3), temperature sensor and humidity sensor.

9. A piston-type simulated lung with precise control of compliance according to claim 5, characterized in that, The outer surface of the guide rod (6) is provided with a protective layer.

10. A piston-type simulated lung with precise control of compliance according to claim 5, characterized in that, The guide rod (6) is equipped with a shock absorber inside.

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