Small animal breathing machine and control method

Abstract

The invention provides a small animal breathing machine and a control method, the small animal breathing machine comprises an air pump set, a breathing control valve, a breathing machine controller and a touch screen displayer, the air pump set comprises a plurality of air pump units arranged in parallel and a silica gel pipeline, the multiple air pump units are connected in parallel, and the air pump units with different flows can be freely combined according to different animal and tidal volume requirements; the air flow of each air pump unit is accurately distributed, meanwhile, the high-precision and large-flow requirements of the breathing machine are met, a three-way pipeline and a valve element are arranged in the breathing control valve, and the pulmonary alveolar connecting end, the three-way pipeline and the air outlet pipeline form an air inlet path; the alveolar connecting end, the three-way pipeline and the waste collecting end form an exhaust gas path, and the valve element can switch the direction of an internal gas path of the three-way pipeline. The breathing control valve controls the airflow direction only through the action of the valve element, so that the air pump unit can operate continuously, frequent starting and stopping are not needed, the service life of the air pump unit is remarkably prolonged, and the response speed is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilators, in particular to a ventilator for small animals. Background Art

[0002] A small animal ventilator is an artificial assisted ventilation device used to assist or control the breathing of animals in scientific research fields such as medical research and animal experiments.

[0003] However, during experiments on small animals, traditional small animal ventilators need to start and stop the air pump during each breathing cycle of the small animal, which increases the mechanical wear of the air pump and shortens its lifespan. At the same time, traditional small animal ventilators usually use a single air pump or a fixed combination of air pumps, and cannot flexibly adjust the air pump configuration according to experimental requirements (such as different animal sizes and tidal volume ranges).

[0004] In view of this, the inventors specially designed a small animal ventilator and method, which resulted in the present case. Summary of the Invention

[0005] In order to solve the above problems, the technical solutions of the present invention are as follows:

[0006] A small animal ventilator, comprising:

[0007] An air pump assembly includes several air pump units and silicone pipes arranged in parallel, wherein the air pump units have an air supply inlet and an air delivery outlet, and the silicone pipes include an air inlet pipe and an air outlet pipe, wherein the air supply inlet is connected to the air inlet pipe via a tee joint, and the air delivery outlet is connected to the air outlet pipe via a tee joint;

[0008] A breathing control valve, one end of which is connected to the port of the outlet pipe, and one end of which is provided with an alveolar connection end and a waste collection end; a three-way pipe and a valve core are provided inside the breathing control valve, and the alveolar connection end, the three-way pipe and the outlet pipe form an air inlet path; the alveolar connection end, the three-way pipe and the waste collection end form an exhaust path, and the valve core is used to switch the internal air path direction of the three-way pipe;

[0009] A ventilator controller is electrically connected to the air pump unit and the valve core. The ventilator controller is used to configure the tidal volume of each air pump unit within an air supply cycle based on the rated air flow, minimum air flow, and tidal volume accuracy parameters of each air pump unit; the valve core switches the air path direction under the command of the ventilator controller;

[0010] The touch screen display is connected to the ventilator controller by electrical signals, and is used by the user to set the tidal volume, respiratory rate and respiratory ratio and transmit signals to the ventilator controller and confirm the air flow parameters of each air pump unit configured by the ventilator controller.

[0011] Preferably, the touch screen display is also used for the user to set the airway pressure parameters. An airway pressure sensor is installed on the silicone tube. The airway pressure sensor is electrically connected to the ventilator controller. The ventilator controller receives data transmitted by the airway pressure sensor and controls the valve core to switch the airway direction inside the three-way pipe based on the comparison result of the pressure signal detected by the airway pressure sensor and the set airway pressure parameter.

[0012] Preferably, it further comprises a pressure relief valve, one end of which is connected to the silicone pipe at the front end of the breathing control valve, and one end of which is connected to the air intake pipe at the front end of the air pump group.

[0013] Preferably, an air filter is installed at the port of the air intake duct.

[0014] Preferably, the air pump unit comprises:

[0015] A multi-cavity air pump having an air inlet and an air outlet, wherein the air inlet is connected to the air supply inlet, and the multi-cavity air pump has a PWM speed regulation function and a speed signal feedback output;

[0016] A three-way high-frequency solenoid valve, one end of which is connected to the air inlet and the air outlet of the multi-cavity air pump through a three-way interface. The three-way high-frequency solenoid valve is connected to the air path of the air pump unit and has a closed state and an open state. The closed state is used to form a circulation loop with the air outlet and block the gas output of the air supply outlet; the open state is used to connect the air outlet with the air supply outlet and open the gas intake of the air inlet at the same time;

[0017] The air pressure sensor is installed at the air outlet of the multi-cavity air pump through a three-way interface;

[0018] The APU controller is electrically connected to the multi-cavity air pump, the three-way high-frequency solenoid valve and the air pressure sensor. The APU controller receives the air flow parameters allocated by the ventilator controller and the real-time pressure parameters transmitted by the air pressure sensor, calculates and outputs a PWM speed regulation signal to drive the multi-cavity air pump to rotate.

[0019] The present invention also discloses a control method for a small animal ventilator, the method comprising the following steps:

[0020] S1. Turn on the ventilator, and the ventilator controller and each air pump unit perform a system self-test. Upload the rated air flow, minimum air flow, and tidal volume accuracy parameters to the ventilator controller for parameter confirmation.

[0021] S2. Air flow configuration: tidal volume, respiratory rate, respiratory ratio, and maximum airway pressure parameters are set through the touch screen display. The ventilator controller receives the parameters set on the touch screen display to calculate and allocate the tidal volume and air supply duration to each air pump unit. After receiving the signal, the APU controller in each air pump unit needs to adjust the air pump speed so that the specified tidal volume can be output within one air supply cycle. This is achieved by adjusting the PWM duty cycle using the classic PID algorithm so that the tidal volume of the air pump unit within the air supply duration is locked to the target value, thereby controlling the motor speed. The data is then uploaded to the ventilator controller and finally confirmed through the touch screen display.

[0022] S3. The ventilator is running, the touch screen display turns on the system, the ventilator controller outputs a start signal, and each air pump unit starts working and locks the speed to deliver gas. During the small animal's inhalation and exhalation process, each air pump unit continuously delivers air and cuts off the air. At the same time, the PWM is updated in real time according to the air output of the air delivery cycle to ensure the stability of the speed of multiple air pump units. During the air delivery process of each air pump unit, if overpressure occurs, the air pump unit cuts off the air, adjusts the air pressure to normal pressure, and then delivers gas. If overpressure occurs again, the cycle continues.

[0023] The technical solution provided by the present invention has the following beneficial effects:

[0024] 1. The present invention uses multiple air pump units in parallel, which can freely combine air pump units with different flow rates according to the needs of different animals and tidal volume. The ventilator controller automatically coordinates the operation of each air pump unit and accurately distributes the air flow of each air pump unit, while meeting the high precision and large flow requirements of the ventilator.

[0025] 2. The present invention sets a breathing control valve. When the animal inhales, the ventilator controller controls the breathing control valve to open, and the gas output by the air pump unit enters the animal's alveoli through this valve; when the animal exhales, the ventilator controller controls the breathing control valve to close, and the exhaled gas enters the exhaust gas collection port through this valve. The breathing control valve only controls the airflow direction through the movement of the valve core, so that the air pump unit can operate continuously without the need for frequent start and stop, which significantly extends the life of the air pump unit and improves the response speed.

[0026] 3. The present invention measures tidal volume through a rotational speed feedback signal, so that the ventilator can provide higher tidal volume output accuracy when there are differences in the performance of the same type of air pumps and changes in the animal's airway pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] in:

[0029] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 It is a schematic diagram of the overall structure of the air pump assembly of the present invention;

[0031] Figure 3 It is a flow chart of starting the ventilator of the present invention;

[0032] Figure 4 This is a flow chart of the flow configuration of the ventilator of the present invention;

[0033] Figure 5 It is a flow chart of the working state of the ventilator of the present invention.

[0034] Description of labels:

[0035] 1. Air pump group; 11. Air pump unit; 111. Multi-chamber air pump; 112. Air inlet; 113. Air outlet; 114. Three-way high-frequency solenoid valve; 115. Air pressure sensor; 116. APU controller; 12. Silicone pipe; 13. Air supply inlet; 14. Air supply outlet; 15. Air inlet pipe; 16. Air outlet pipe; 2. Breathing control valve; 21. Alveolar connection end; 22. Waste collection end; 3. Ventilator controller; 4. Touch screen display; 5. Three-way connector; 6. Airway pressure sensor; 7. Pressure relief valve; 8. Air filter. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] See also Figures 1 to 5 , is a small animal ventilator as the best embodiment of the present invention, comprising:

[0038] The air pump group 1 includes several air pump units 11 and silicone tubes 12 arranged in parallel. Several air pump units 11 have an air supply inlet 13 and an air delivery outlet 14. The silicone tube 12 includes an air inlet pipe 15 and an air outlet pipe 16. The air supply inlet 13 is connected to the air inlet pipe 15 through a three-way joint 5, and the air delivery outlet 14 is connected to the air outlet pipe 16 through a three-way joint 5. Multiple air pump units 11 can be connected in parallel to freely combine air pump units 11 with different flow rates according to the needs of different animals and tidal volume. The small flow air pump works first to ensure accuracy, and the large flow air pump is started on demand to meet peak demand;

[0039] The breathing control valve 2 has one end connected to the port of the outlet pipe 16, and one end thereof is provided with an alveolar connecting end 21 and a waste collecting end 22; the breathing control valve 2 has a three-way pipe and a valve core inside, and the alveolar connecting end 21, the three-way pipe and the outlet pipe 16 form an air inlet air path; the alveolar connecting end 21, the three-way pipe and the waste collecting end 22 form an exhaust air path, and the valve core is used to switch the internal air path direction of the three-way pipe. When the animal inhales, the breathing control valve 2 opens, and the output gas of the air pump unit 11 enters the animal's alveoli through this valve; when the animal exhales, this valve closes, and the exhaled gas enters the waste gas collecting port through this valve. The two-way air path is isolated, which can avoid gas mixing and ensure gas purity. In order not to generate greater resistance during the exhalation process, the breathing control valve 2 should be a large-flow valve, and the installation position should be as close to the animal side as possible;

[0040] The ventilator controller 3 is electrically connected to the air pump unit 11 and the valve core. The ventilator controller 3 is used to configure the tidal volume of each air pump unit 11 within an air supply cycle according to the rated air flow, minimum air flow, and tidal volume accuracy parameters of each air pump unit 11; the valve core switches the air path direction under the command of the ventilator controller 3;

[0041] The touch screen display 4 is electrically connected to the ventilator controller 3 for the user to set the tidal volume, respiratory rate and respiratory ratio and transmit signals to the ventilator controller 3 and confirm the air flow parameters of each air pump unit 11 configured by the ventilator controller 3.

[0042] The pipeline design eliminates the need to stop the air pump during both exhalation and inhalation, reducing the number of air pump starts and stops and extending the life of the ventilator. The modular design allows for flexible configuration of different air pump units11 for different animals and tidal volume requirements, while reducing the cost of system upgrades and maintenance.

[0043] For details, please refer to Figures 1 and 2 The touch screen display 4 is also used by the user to set the airway pressure parameters. An airway pressure sensor 6 is installed on the silicone tube 12. The airway pressure sensor 6 is electrically connected to the ventilator controller 3. The ventilator controller 3 receives the data transmitted by the airway pressure sensor 6 and controls the valve core to switch the direction of the air path inside the three-way pipe according to the comparison result of the pressure signal detected by the airway pressure sensor 6 and the set airway pressure parameter. The airway pressure sensor 6 is used to measure the air pressure in the airway in real time. When the air pressure is higher than the set critical value (the maximum allowable air pressure of the animal alveoli), the ventilator controller 3 stops the air pump and closes the breathing control valve 2 to achieve intelligent safety protection.

[0044] For details, please refer to Figure 1, pressure relief valve 7, one end of the pressure relief valve 7 is connected to the silicone pipe 12 at the front end of the breathing control valve 2, and one end thereof is connected to the air inlet pipe 15 at the front end of the air pump group 1. The pressure relief valve 7 is connected to the air inlet pipe 15 and the air outlet pipe 16. When the ventilator controller 3 fails and the airway pressure sensor 6 fails, the ventilator controller 3 will not be able to stop the air pump in time when the airway pressure is too high. In order to prevent this situation from causing harm to the animal, a physical pressure relief valve 7 is installed to ensure the safety of the animal while increasing the service life of the ventilator.

[0045] For details, please refer to Figure 1 The port of the air intake pipe 15 is equipped with an air filter 8 to filter impurities and water vapor in the air or air-oxygen mixed gas entering the air intake pipe 15, thereby extending the service life of the air pump;

[0046] For details, please refer to Figure 2 , the air pump unit 11 includes:

[0047] The multi-cavity air pump 111 has an air inlet 112 and an air outlet 113. The air inlet 112 is connected to the air supply inlet 13. The multi-cavity air pump 111 has a PWM speed regulation function and a speed signal feedback output. The multi-cavity air pump 111 outputs a stable air flow, and can achieve precise tidal volume control in conjunction with speed control.

[0048] The three-way high-frequency solenoid valve 114 is connected to the air inlet 112 and the air outlet 113 of the multi-cavity air pump 111 at one end through a three-way interface. The three-way high-frequency solenoid valve 114 is connected to the air path of the air pump unit 11 and has a closed state and an open state. The closed state is used to form a circulation loop with the air outlet 113 and the air inlet 112, blocking the gas output of the air supply outlet 14; the open state is used to connect the air outlet 113 with the air supply outlet 14 and open the gas intake of the air inlet 112 at the same time. The three-way high-frequency solenoid valve 114 and the breathing control valve 2 are used to further avoid the frequent start and stop of the air pump. The air pump does not need to be shut down during operation. The ventilator controller 3 controls the three-way high-frequency solenoid valve 114 to realize the on-off of the output gas, thereby increasing the service life of the air pump. When the three-way high-frequency solenoid valve 114 is closed, the air outlet 113 and the air inlet 112 form a circulation loop, blocking the gas output of the air supply outlet 14. When the three-way high-frequency solenoid valve 114 is opened, the air outlet 113 is connected to the air supply outlet 14, and the gas intake of the air inlet 112 is opened at the same time. During the whole process, the air pump does not need to be shut down, and intermittent gas supply can be achieved only through the three-way high-frequency solenoid valve 114, which significantly extends the life of the air pump unit 11 and improves the response speed;

[0049] The air pressure sensor 115 is installed at the air outlet 113 of the multi-cavity air pump 111 through a three-way interface; the present invention calculates the air flow rate through the motor speed and air pressure, so the air pressure sensor 115 is required to measure the air pressure at the air pump outlet in real time. The ventilator controller 3 calculates the air flow rate based on the real-time air pressure, motor speed and air pump performance characteristics, thereby realizing precise tidal volume control, and the air pressure sensor 115 is inexpensive, which reduces the cost of the ventilator.

[0050] APU controller 116, APU controller 116 is electrically connected to the multi-chamber air pump 111, the three-way high-frequency solenoid valve 114 and the air pressure sensor 115. The APU controller 116 receives the air flow parameters, air pump performance curve and real-time pressure parameters transmitted by the air pressure sensor 115 assigned by the ventilator controller 3, calculates and outputs a PWM speed control signal to drive the multi-chamber air pump 111 to rotate. The ventilator controller 3 inputs the set parameters. During operation, the APU controller 116 calculates the desired air pump speed based on the set parameters, air pump performance curve and real-time airway pressure, and then outputs a PWM speed control signal to drive the air pump motor to rotate. The PID algorithm is used to adjust the PWM speed control signal according to the speed feedback, so that the air pump can output at the desired air flow rate. The APU controller 116 uses PID algorithm + PWM speed control + multi-pump collaboration to achieve a comprehensive improvement in flow control accuracy, response speed and system reliability while maintaining a simple structure.

[0051] For details, please refer to Figure 2 The three-way high-frequency solenoid valve 114 has an air supply outlet 14, and the air supply outlet 14 is connected to the air outlet pipe 16 through a three-way interface.

[0052] A control method for a small animal ventilator, characterized in that it comprises the following steps:

[0053] S1. Turn on the ventilator, and the ventilator controller 3 and each air pump unit 11 perform a system self-check. Upload the maximum air flow parameter to the ventilator controller 3 for parameter confirmation, and wait for the touch screen display 4 to display success.

[0054] S2. Air flow configuration: tidal volume, respiratory rate, respiratory ratio and maximum airway pressure parameters are set through the touch screen display 4. The ventilator controller 3 receives the parameters set on the touch screen display 4 to calculate and allocate the tidal volume and air supply duration to each air pump unit 11. After receiving the signal, the APU controller 116 in each air pump unit 11 needs to adjust the air pump speed so that the specified tidal volume can be output within one air supply cycle. This is achieved by adjusting the PWM duty cycle using the classic PID algorithm so that the tidal volume of the air pump unit 11 within the air supply duration is locked to the target value, thereby controlling the motor speed. The data is then uploaded to the ventilator controller 3 and finally confirmed through the touch screen display 4.

[0055] S3. The ventilator is running, the touch screen display 4 turns on the system, the ventilator controller 3 outputs a start signal, and each air pump unit 11 starts working and locks the speed to deliver gas. During the inhalation and exhalation process of the small animal, each air pump unit 11 continuously delivers air and cuts off the air. The APU controller 116 updates the PWM in real time according to the air output of the air delivery cycle to ensure the stability of the speed of the multi-cavity air pump 111. During the air delivery process of each air pump unit 11, if overpressure occurs, the air pump unit 11 cuts off the air, adjusts the air pressure to normal pressure, and then delivers gas. If overpressure occurs again, the cycle continues.

[0056] Specifically, in step S2, the method for calculating the tidal volume of each air pump unit 11 includes:

[0057] S21, select air pump unit 11:

[0058] T in =n / ((m+n)f); s=(1+m / n)fv;

[0059] Where: f is the set respiratory frequency, m:n is the set respiratory ratio, v is the set total tidal volume, T in is the inspiratory time, s is the overall air flow requirement of the ventilator, and according to the rated air flow of each air pump unit 11, find an integer K such that That is, the sum of the rated air flow of the air pump units 11 from No. 1 to K is greater than the overall tidal volume requirement s of the ventilator, where is the rated air flow of the Kth air pump unit 11;

[0060] S22, calculate the air flow of each air pump unit 11:

[0061]

[0062] Where: s i is the air flow rate of the i-th air pump unit 11, is the minimum air flow of the Kth air pump unit 11, is the rated air flow of the i-th air pump unit 11;

[0063] S23, Tidal Volume Distribution:

[0064] Pump units 2 to K, 11, tidal volume

[0065]

[0066] Where: is the tidal volume corresponding to each pulse of the i-th air pump unit 11;

[0067] The remaining tidal volume is allocated to pump unit 11:

[0068]

[0069] Where: v 1 is the tidal volume of pump unit 11, v k is the tidal volume of air pump unit 11, No. K.

[0070] At this point, the ventilator controller has calculated the tidal volume of each air pump unit 11 in one air supply cycle. The tidal volume enables each air pump unit 11 to operate at a flow rate greater than its minimum flow rate and is an integer multiple of its accuracy.

[0071] Specifically, after the air pump unit 11 receives the tidal volume demand from the ventilator controller 3, it needs to adjust the air pump speed so that the specified tidal volume can be output within one air supply cycle. This is achieved by adjusting the PWM duty cycle to control the motor speed. In step S2, the PID algorithm is used to adjust the PWM duty cycle based on the speed feedback as follows:

[0072] a. Cumulative error of initial tidal volume e acc =0, tidal volume error e in the previous measurement cycle last =0, waiting for the gas supply process of the gas supply cycle to end;

[0073] b. Measure the number of pulses p output by the encoder during the air supply process;

[0074] c. According to the encoder output pulse number p and the average pressure of the air pump unit 11 air outlet 14 during the air delivery process Calculate actual tidal volume in is the tidal volume attenuation coefficient of the air pump under pressure;

[0075] d. Calculate the tidal volume deviation e = v target -v actual ;

[0076] e. Update the cumulative error e acc =e acc +e;

[0077] Update duty cycle r = K p e+K i e acc +K d (ee last );

[0078] Update last =e;

[0079] Jump to a and continue waiting for the gas supply process to end;

[0080] Where: v actualis the actual tidal volume, r is the PWM duty cycle, p is the number of encoder output pulses of the air pump unit 11 during the air supply time, v target To set the tidal volume, K p is the proportional gain, K i is the integral gain, K d is the differential gain.

[0081] To sum up, the present invention adopts multiple air pump units 11 in parallel, and can freely combine air pump units 11 with different flow rates according to the requirements of different animals and tidal volume, and the ventilator controller 2 automatically coordinates the operation of each air pump unit 11, accurately distributes the air flow of each air pump unit 11, and meets the high precision and large flow requirements of the ventilator at the same time. The present invention sets a breathing control valve 2 and a three-way high-frequency solenoid valve 114, so that the air pump unit 11 can operate continuously without frequent start and stop, which significantly extends the life of the air pump unit 11 and improves the response speed.

[0082] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A small animal ventilator, characterized in that: include: An air pump assembly (1) comprises a plurality of air pump units (11) and a silicone pipe (12) arranged in parallel, wherein the plurality of air pump units (11) have an air supply inlet (13) and an air delivery outlet (14), and the silicone pipe (12) comprises an air inlet pipe (15) and an air outlet pipe (16), wherein the air supply inlet (13) is connected to the air inlet pipe (15) via a three-way joint (5), and the air delivery outlet (14) is connected to the air outlet pipe (16) via the three-way joint (5); A breathing control valve (2) is provided with an alveolar connection end (21) and a waste collection end (22) at one end, wherein the breathing control valve (2) has a three-way pipe and a valve core inside, wherein the alveolar connection end (21), the three-way pipe and the air outlet pipe (16) form an air intake path; wherein the alveolar connection end (21), the three-way pipe and the waste collection end (22) form an air exhaust path, and the valve core is used to switch the internal air path direction of the three-way pipe; A ventilator controller (3) is electrically connected to the air pump unit (11) and the valve core, and is used to configure the tidal volume of each air pump unit (11) within an air supply cycle according to the rated air flow rate, minimum air flow rate, and tidal volume accuracy parameters of each air pump unit (11); the valve core switches the air path direction under the instruction of the ventilator controller (3); The touch screen display (4) is electrically connected to the ventilator controller (3) and is used for the user to set the tidal volume, respiratory rate and respiratory ratio and transmit signals to the ventilator controller (3) and confirm the air flow parameters of each air pump unit (11) configured by the ventilator controller (3).

2. A small animal ventilator according to claim 1, characterized in that: The touch screen display (4) is also used for the user to set the airway pressure parameter. An airway pressure sensor (6) is installed on the silicone tube (12). The airway pressure sensor (6) is connected to the ventilator controller (3) via an electrical signal. The ventilator controller (3) receives data transmitted by the airway pressure sensor (6) and controls the valve core to switch the airway direction inside the three-way tube according to the comparison result between the pressure signal detected by the airway pressure sensor (6) and the set airway pressure parameter.

3. A small animal ventilator according to claim 1, characterized in that: It also includes a pressure relief valve (7), one end of which is connected to the silicone pipe (12) at the front end of the breathing control valve (2), and one end of which is connected to the air intake pipe (15) at the front end of the air pump group (1).

4. A small animal ventilator according to claim 1, characterized in that: An air filter (8) is installed at the port of the air intake pipe (15).

5. A small animal ventilator according to claim 1, characterized in that: The air pump unit (11) comprises: A multi-cavity air pump (111) has an air inlet (112) and an air outlet (113), wherein the air inlet (112) is connected to the air supply inlet (13), and the multi-cavity air pump (111) has a PWM speed regulation function and a speed signal feedback output; A three-way high-frequency solenoid valve (114), one end of which is connected to the air inlet (112) and the air outlet (113) of the multi-cavity air pump (111) through a three-way interface. The three-way high-frequency solenoid valve (114) is connected to the air path of the air pump unit (11) and has a closed state and an open state. The closed state is used to form a circulation loop with the air outlet (113) and the air inlet (112), thereby blocking the gas output of the air delivery outlet (14); the open state is used to connect the air outlet (113) with the air delivery outlet (14) and simultaneously open the air inlet (112) for gas intake; An air pressure sensor (115) is installed at the air outlet (113) of the multi-cavity air pump (111) through a three-way interface; The APU controller (116) is electrically connected to the multi-cavity air pump (111), the three-way high-frequency solenoid valve (114) and the air pressure sensor (115). The APU controller (116) receives the air flow parameter assigned by the ventilator controller (3) and the real-time pressure parameter transmitted by the air pressure sensor (115), calculates and outputs a PWM speed regulation signal to drive the multi-cavity air pump (111) to rotate.

6. A method for controlling a small animal ventilator according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Turn on the ventilator, and the ventilator controller (3) and each air pump unit (11) perform a system self-check, and upload the rated air flow, minimum air flow, and tidal volume accuracy parameters to the ventilator controller (3) for parameter confirmation; S2, air flow configuration, setting the tidal volume, respiratory rate, respiratory ratio and maximum airway pressure parameters through the touch screen display (4), the ventilator controller (3) receives the parameters set by the touch screen display (4), calculates and allocates the tidal volume and air supply duration of each air pump unit (11), and the APU controller (116) in each air pump unit (11) needs to adjust the air pump speed after receiving the signal so that the specified tidal volume can be output within an air supply cycle. This is achieved by adjusting the PWM duty cycle using a classic PID algorithm so that the tidal volume of the air pump unit (11) within the air supply duration is locked to the target value, thereby controlling the motor speed, and then uploading it to the ventilator controller (3), and finally confirming it through the touch screen display (4); S3, the ventilator is running, the touch screen display (4) turns on the system, the ventilator controller (3) outputs a start signal, each air pump unit (11) starts working and locks the speed to carry out gas delivery. During the inhalation and exhalation process of the small animal, each air pump unit (11) continuously delivers air and cuts off the air, and at the same time, the PWM is updated in real time according to the air output of the delivery cycle to ensure the stability of the speed of multiple air pump units (11); during the delivery process of each air pump unit (11), if overpressure occurs, the air pump unit (11) cuts off the air, adjusts the air pressure to normal pressure, and then carries out gas delivery. If overpressure occurs again, the cycle continues.

7. The control method of a small animal ventilator according to claim 6, characterized in that: In step S2, the method for calculating the tidal volume of each air pump unit (11) includes: S21. Select the air pump unit (11): T in =n / ((m+n)f);s=(1+m / n)fv; Where: f is the set respiratory frequency, m:n is the set respiratory ratio, v is the set total tidal volume, T in is the inspiratory time, s is the overall air flow requirement of the ventilator, and according to the rated air flow of each air pump unit (11), find an integer K such that That is, the sum of the rated air flow of the air pump units 1 to K (11) is greater than the overall tidal volume requirement s of the ventilator, where is the rated gas flow of the Kth air pump unit; S22, calculate the air flow rate of each air pump unit (11): Where: s i is the air flow rate of the i-th air pump unit (11), is the minimum air flow of the Kth air pump unit (11), is the rated air flow rate of the i-th air pump unit (11); S23, Tidal Volume Distribution: Air pump units 2 to K (11), tidal volume Where: is the tidal volume corresponding to each pulse of the i-th air pump unit (11); The remaining tidal volume is allocated to the first pump unit (11): Where: v 1 is the tidal volume of the first air pump unit (11), v k is the tidal volume of the Kth air pump unit (11).

8. The control method of a small animal ventilator according to claim 6, characterized in that: The process of adjusting the PWM duty cycle using the PID algorithm according to the speed feedback in step S2 is as follows: a. Cumulative error of initial tidal volume e acc =0, tidal volume error e in the previous measurement cycle last =0, waiting for the gas supply process of the gas supply cycle to end; b. Measure the number of pulses p output by the encoder during the air supply process; c. According to the encoder output pulse number p and the average pressure of the air delivery outlet (14) of the air pump unit (11) during the air delivery process Calculate actual tidal volume in is the tidal volume attenuation coefficient of the air pump unit (11) under pressure; d. Calculate the tidal volume deviation e = v target -v actual ; e. Update the cumulative error e acc =e acc +e; Update duty cycle r = K p e+K i e acc +K d (ee last ); Update last =e; Jump to a and continue waiting for the gas supply process to end; Where: v actual is the actual tidal volume, r is the PWM duty cycle, p is the number of encoder output pulses of the air pump unit (11) during the air supply time, v target To set the tidal volume, K p is the proportional gain, K i is the integral gain, K d is the differential gain.

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