CN113012545B

CN113012545B - Device for simulating human body breathing flow

Info

Publication number: CN113012545B
Application number: CN202110165950.XA
Authority: CN
Inventors: 朱振山; 琚亚平; 张楚华
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2022-12-06
Anticipated expiration: 2041-02-05
Also published as: CN113012545A

Abstract

The present disclosure discloses a device for simulating human respiratory flow, comprising: the device comprises a control unit, a driving unit and a breathing simulation unit, wherein the control unit is used for controlling the breathing simulation unit; the control unit is used for controlling the driving force output by the driving unit according to the human body respiratory flow curve; the driving unit is used for driving the respiration simulation unit to simulate the respiration flow of the human body; the respiration simulation unit is used for simulating the respiration flow of the human body and outputting respiration boundary conditions. The method and the device can output the respiratory flow data of different crowds in different states as boundary conditions of experimental measurement.

Description

Device for simulating human body breathing flow

Technical Field

The disclosure belongs to the technical field of biomechanics, and particularly relates to a device for simulating human breath flow.

Background

The human body respiratory flow experiment shows the accurate and visual human body respiratory flow process through high-precision measuring instruments such as PIV and LDV, is an important way for researching the human body respiratory flow, and has important significance for understanding the human body respiratory flow and deeply researching related theories. The device capable of accurately simulating the respiratory flow of the human body is the key of the respiratory flow experiment of the human body.

The existing human respiratory flow device adopts a greatly simplified method to provide sinusoidal experimental boundary conditions for respiratory flow experiments, and human beings cannot breathe the mechanical respiratory flow curves.

The existing device for accurately simulating the human respiratory flow can provide high-precision and various types of experimental boundary conditions of the human respiratory flow for respiratory flow experiments. The device can simulate various breathing movements from infants to adults, such as calm breathing, light movement breathing, heavy movement breathing and the like through PLC programming. Has wide application prospect in the field of human body respiration experiments.

The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Disclosure of Invention

In view of the deficiencies in the prior art, the present disclosure is directed to a device for simulating human respiratory flow, which is capable of providing high-precision and various types of boundary conditions for human respiratory flow experiments.

In order to achieve the above object, the present disclosure provides the following technical solutions:

a device for simulating respiratory flow in a human, comprising: the device comprises a control unit, a driving unit and a breathing simulation unit, wherein the control unit is used for controlling the breathing simulation unit;

the control unit is used for controlling the driving force output by the driving unit according to the human body respiratory flow curve;

the driving unit is used for driving the respiration simulation unit to simulate the respiration flow of the human body;

the breath simulation unit is used for simulating the breath flow of the human body and outputting a breath boundary condition.

Preferably, the control unit comprises a PLC controller for programming the human body respiratory flow curve into a rotational speed curve executable by the driving unit.

Preferably, the driving unit comprises a motor and a connecting mechanism, and the connecting mechanism converts the rotating torque output by the motor into torque for the breathing simulation unit to perform breathing simulation movement.

Preferably, the breathing simulation unit comprises a piston assembly.

Preferably, the connecting mechanism comprises a crankshaft connecting rod.

Preferably, the piston assembly comprises a piston and a sealed piston cylinder, and the piston reciprocates in the piston cylinder under the action of the driving unit to simulate human breathing.

Preferably, the device further comprises a speed reducer, and the speed reducer is connected with the motor to enhance the output torque of the motor.

Preferably, the apparatus further comprises a bubble removal means.

Preferably, the device further comprises a working medium storage.

Preferably, the motor includes a servo motor and a stepping motor.

Compared with the prior art, the beneficial effect that this disclosure brought does:

1. the respiratory tract disease diagnosis and treatment device more conforms to the real respiratory flow condition of a human body, is favorable for deeply knowing the respiratory flow process in the respiratory tract of the human body and knowing the generation and development mechanisms of the respiratory tract diseases, and has important theoretical reference and practical application values for diagnosing and treating the respiratory tract diseases.

2. Similar devices in the past can only provide one working condition and are boundary conditions of sinusoidal respiratory flow experiments. The present disclosure can be programmed to output respiratory flow data for different populations, such as infants, adults and respiratory disease patients, in different states, such as rest, light exercise, moderate exercise and severe exercise, as experimentally measured boundary conditions.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for simulating human respiratory flow according to an embodiment of the present disclosure;

FIG. 2 is a schematic representation of the relationship of crankshaft connecting rod and piston motion provided by another embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating boundary condition curves corresponding to three tidal volumes provided by another embodiment of the present disclosure;

fig. 4 is a schematic diagram of a comparison of a true respiratory flow curve of an adult during quiet breathing and an accurate measurement of the output of the device using a PIV measurement system according to another embodiment of the present disclosure.

Detailed Description

Specific embodiments of the present disclosure will be described in detail below with reference to fig. 1 to 4. While specific embodiments of the disclosure are shown in the drawings, it should be understood that the disclosure can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It should be noted that certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, various names may be used to refer to a component. The description and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description which follows is a preferred embodiment of the invention, but is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present disclosure is to be determined by the terms of the appended claims.

For the purpose of facilitating an understanding of the embodiments of the present disclosure, the following detailed description is to be construed in conjunction with the accompanying drawings, and the various drawings are not intended to limit the embodiments of the present disclosure.

In one embodiment, as shown in fig. 1, the present disclosure provides an apparatus for simulating the respiratory flow of a human, comprising: the device comprises a control unit, a driving unit and a breathing simulation unit, wherein the control unit is used for controlling the breathing simulation unit;

the respiration simulation unit is used for simulating the respiration flow of the human body and outputting respiration boundary conditions.

In this embodiment, the control unit may write a corresponding control program according to a human respiratory flow curve obtained by measurement of the spirometer, and convert the control program into a rotational speed curve executable by the driving unit. The driving unit drives the respiration simulation unit to simulate the human body respiration flow under the control of the control unit, so that accurate respiration experiment boundary conditions in various respiration states can be provided for the human body respiration flow experiment.

In another embodiment, the control unit comprises a PLC controller for programming the human respiratory flow curve into a rotational speed curve executable by the drive unit.

In this embodiment, a certain number of discrete points on the rotation speed cycle curve are extracted, and a corresponding PLC program is programmed according to the discrete points. The drive unit drives the breath simulation unit to simulate the breath flow of the human body under the control of the PLC, thereby providing accurate breath experiment boundary conditions in various breath states for the breath flow experiment of the human body.

The human respiratory flow curve may be a respiratory curve of a human at any age, or may be a respiratory flow curve of the same human in different states (for example, a calm state, a light exercise state, a strenuous exercise state, and the like).

In another embodiment, the driving unit comprises a motor and a connecting mechanism, and the connecting mechanism converts the rotation torque output by the motor into torque for the breathing simulation unit to perform breathing simulation movement.

In this embodiment, the connecting mechanism is usually connected by a crankshaft, and the rotating torque output by the motor can be converted into the reciprocating motion of the piston through a crankshaft connecting rod, and meanwhile, the torque acting on the crankshaft is converted into the torque output by the piston. Wherein, fig. 2 shows the relationship between the motion of the crankshaft connecting rod and the piston, as shown in fig. 2, when the crankshaft with the eccentricity a rotates counterclockwise at the angular velocity of ω, the piston will move downward at the velocity V, and according to the cosine theorem, the following can be obtained:

after time at Δ t, the angle becomes θ + Δ t · ω, the distance b of the piston from the crankshaft becomes b + Δ t · V, and the eccentricity a of the crankshaft and the connecting rod length c are both constant. Multiplying both sides of the above equation by 2ab simultaneously and taking the derivative with respect to time t yields:

2acosθ·V-2ab·sinθ·ω＝2b.V (2)

the relation between the crankshaft angular velocity omega and the piston repeated motion velocity V can be obtained by arranging the above formula:

in the formula (3), the distance b between the piston and the axis of the crankshaft can be obtained by the cosine law:

through the accurate control of the PLC, when the piston does once reciprocating motion, the crankshaft does not need to rotate for a circle like outputting a sine curve, but only needs to rotate downwards from an initial position S to a position R, and boundary conditions of an inspiration phase are provided for a respiratory flow experiment; then the crankshaft rotates reversely to the initial position S, and the boundary condition of the expiration stage is output. When the tidal volume of the subject changes, the location R in fig. 2 moves up the circle in fig. 2 as the tidal volume decreases or moves down the circle in fig. 2 as the tidal volume increases. Illustratively, fig. 3 depicts a graph of the boundary conditions of an adult output by the device over a tidal volume range of 400-600ml (400 ml for an adult in a calm state, 500ml for an adult in a light exercise state, and 600ml for an adult in a heavy exercise state), wherein the upper horizontal axis represents inspiratory motion and the lower horizontal axis represents expiratory motion. When the tidal volume changes along with time, the rotating speed of the crankshaft also changes, so that the piston is driven to reciprocate at different frequencies, and a boundary condition curve shown in fig. 3 is output.

In another embodiment, the piston assembly comprises a piston and a sealed piston cylinder, and the piston reciprocates in the piston cylinder under the action of the driving unit to simulate human respiration.

In this embodiment, as shown in fig. 2, the piston performs a reciprocating motion once under the precise control of the PLC program, and the crankshaft does not need to rotate once as an output sine curve, but only needs to rotate downward from the initial position S to the position R to output the boundary condition of the suction phase; then the crankshaft rotates reversely to the initial position S, and the boundary condition of the expiration stage is output. When the study object is a teenager, the position R in the graph moves upwards along the circle of the graph along with the smaller tidal volume of the teenager; when the research object is changed from a rest state to a motion state, the rotating speed of the crankshaft at each moment is changed according to the change of the respiratory flow curve.

In another embodiment, the device further comprises a speed reducer connected with the motor to enhance the output torque of the motor.

In this embodiment, if the motor is difficult to drive the piston assembly due to the output torque being too small, the rotational speed of the motor needs to be reduced by the speed reducer to increase the output torque of the motor. In the experiment, generally can choose for use planetary reducer, planetary reducer is the mechanism that utilizes the gear to carry out power transmission, and the gear wheel that the number of teeth is many is engaged through the little pinion that the number of teeth is few to reach the mesh that slows down and increase the moment of torsion. Illustratively, if the output rated power of the motor is 1kW, but the rated output torque is only 4N · m, the reduction ratio of the speed reducer is 1: 50, and the transmission efficiency is about 75%, so that the rated torque finally output by the motor through the speed reducer can reach 4 × 50 × 0.75=150n · m.

In another embodiment, the apparatus further comprises bubble removal means.

In this embodiment, the bubble removing device is provided with an upper valve and a lower valve, and a transparent cavity which is transparent and has a certain space is arranged in the middle of the bubble removing device. In the process of removing bubbles, firstly, closing a lower valve, opening an upper valve, and injecting an experimental working medium (a common working medium is a mixture of glycerol and water or a mixture of glycerol, water and sodium iodide) from the upper part; secondly, after injecting an experimental working medium with half of the volume of the cavity into the cavity, closing the upper valve and opening the lower valve; and finally, starting the power system, and along with the operation of the power system, the bubbles attached to the wall surface of the pipeline and the inner wall surface of the experimental model can fall off from the wall surface in the process that the power system simulates one inhalation and one exhalation of a human body. The air that reserves in this device top cavity this moment also can take place the inflation or be compressed along with the change of pipeline internal pressure to working medium and the interior working medium interaction of pipeline below in the increase cavity greatly strengthen the interior bubble of pipeline below and pass through the possibility that vertical pipeline got into the top cavity. A large amount of bubbles enter the cavity under the influence of buoyancy and then do not return to a pipeline below the cavity, and the bubbles in the experimental working medium can be completely removed after about ten or more breathing cycles. The air bubbles in the model and the pipeline are removed completely, so that a good measuring environment can be provided for later experimental measurement.

In another embodiment, the device further comprises a working fluid storage device.

In this embodiment, the working medium storage device mainly includes a measuring cylinder, in which an experimental working medium (specific components have been given in the foregoing embodiments) is stored, and can detect and verify an experimental boundary condition output by the experiment platform power system. By continuously recording the time and location of the occurrence of the highest and lowest levels in the graduated cylinder, the inspiratory time, expiratory time, total respiratory cycle time and tidal volume output by the device of the present disclosure can be determined.

In another embodiment, the motor includes a servo motor and a stepper motor.

Fig. 4 is a schematic diagram comparing the real respiratory flow curve of an adult in quiet breathing with the result of accurately measuring the output of the device by using a PIV measuring system. As shown in fig. 4, after multiple measurements by the PIV measurement system, it is confirmed that the uncertainty of the actual output experimental boundary condition of the power system is about 2% (uncertainty analysis is a study and estimation of measurement uncertainty, which means that unavoidable measurement errors caused by various factors during measurement, and uncertainty accompanying the experimental measurement cannot be eliminated unlike errors occurring during the experimental measurement).

Claims

1. A device for simulating respiratory flow in a human, comprising: the device comprises a control unit, a driving unit and a breathing simulation unit, wherein the control unit is used for controlling the breathing simulation unit;

the control unit is used for controlling the driving force output by the driving unit according to the human body respiratory flow curve, and comprises a PLC (programmable logic controller) used for programming the human body respiratory flow curve into a PLC program executable by the driving unit;

the drive unit is used for driving the respiration simulation unit to simulate the respiration flow of a human body, and comprises a motor and a connecting mechanism, wherein the connecting mechanism converts a rotation torque output by the motor into a torque which can be used for the respiration simulation unit to carry out respiration simulation motion;

the respiration simulation unit comprises a piston assembly, the piston assembly reciprocates under the control of a PLC program to simulate the respiration flow of a human body and output respiration boundary conditions.

2. The apparatus of claim 1, wherein the piston assembly comprises a piston and a sealed piston cylinder, the piston reciprocating within the piston cylinder under the action of the drive unit simulating human breathing.

3. The device of claim 1, further comprising a speed reducer coupled to the motor to increase an output torque of the motor.

4. The device of claim 1, wherein the device further comprises a bubble removal device.

5. The device of claim 1, wherein the device further comprises a working fluid reservoir.

6. The apparatus of claim 1, wherein the motor comprises a servo motor and a stepper motor.