Human respiration simulation system and human respiration simulation method

Abstract

The invention relates to the technical field of breathing state simulation, in particular to a human body breathing simulation system which is characterized by comprising a thoracic cavity structure model and a thoracic cavity driving assembly, the thoracic cavity driving assembly is provided with three driving shafts which are driven by the same servo motor and output linear motion, and the three driving shafts keep synchronous motion; a first connecting rod and a second connecting rod are arranged on the two sides of the sternum of the thoracic cavity structure model respectively, and the first connecting rod and the second connecting rod are connected with the tail ends of all the rib brackets on the same side; and three driving shafts which are driven by the same servo motor and output linear motion are respectively connected with the first connecting rod, the second connecting rod and the sternum and are used for pushing the sternum and all rib brackets to expand. As a calibration device for non-contact breathing parameter measurement, interference of an external environment is avoided, and the accuracy of a detection result is improved; the single servo motor synchronously drives the sternum and all the rib supports, and strict synchronization of thoracic cavity fluctuation and rib expansion is achieved.

Description

Technical Field

[0001] This application relates to the field of respiratory state simulation technology, and in particular to a human respiratory simulation system and a human respiratory simulation method. Background Technology

[0002] Breathing, as one of the basic vital signs of the human body, is directly related to human health, and some parameters of the respiratory process can serve as important reference indicators for disease diagnosis. For example, respiratory rate can measure the quality of heart function and the normality of gas exchange; respiratory amplitude can predict the movement of upper abdominal tissues, thus ensuring precise tracking and positioning in ultrasound-focused surgery and laser surgery; respiratory intensity is an important reference for airway obstruction and respiratory muscle fatigue. In addition, continuous monitoring of breathing can help to detect and prevent certain sudden diseases, such as sleep apnea. Therefore, the measurement of respiratory parameters is of guiding significance.

[0003] Currently, respiratory parameter measurement methods are mainly divided into contact and non-contact measurements. The more mature and successfully applied multidimensional contact measurement methods in clinical practice include respiratory airflow detection, photoplethysmography (PPG), impedance respiratory monitoring, and transformer detection. However, contact measurements are typically wearable devices, which are invasive and often inconvenient for subjects. Furthermore, contact measurements require high levels of safety and technical expertise, making them unsuitable for casual monitoring in daily life. Non-contact measurement methods, on the other hand, avoid contact with the user and allow for remote measurement; therefore, non-contact measurement represents the future direction of respiratory measurement technology. However, due to deficiencies in robustness and accuracy, they have not been widely adopted in clinical practice or routine health monitoring. Therefore, calibrating the accuracy of non-contact measurements is an essential step towards clinical application.

[0004] Currently, comparing the results of non-contact measurements with those from commercial monitoring instruments or manual counting is a common approach. However, current commercial monitoring instruments mostly detect changes in chest cavity expansion and contraction during human respiration using methods such as radar ranging, optical flow identification, and microwave ranging. These methods are easily affected by the environment and struggle to effectively distinguish interfering movements, impacting measurement accuracy. While manual counting of chest cavity expansion during respiration offers higher accuracy, it is not conducive to automated integration. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a human breathing simulation system and a human breathing simulation method, which solves the technical problems that the manual counting of breathing and chest expansion is not conducive to automated integration and that commercial monitoring instruments are easily affected by environmental interference and have difficulty distinguishing between interfering movement and breathing movement.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted in this application include:

[0009] In a first aspect, embodiments of this application provide a human breathing simulation system, including: a thoracic cavity structure model and a thoracic cavity drive assembly, wherein the thoracic cavity drive assembly has three drive shafts that output linear motion driven by the same servo motor, and the three drive shafts maintain synchronous motion;

[0010] The thoracic cavity structure model has a first link and a second link on both sides of the sternum, and both the first link and the second link are connected to the ends of all the rib supports on the same side.

[0011] The three drive shafts that output linear motion, driven by the same servo motor, are connected to the first link, the second link, and the sternum, respectively, to push the sternum and all the rib supports to expand.

[0012] Optionally, in one specific embodiment, the thoracic cavity drive assembly includes a first transmission structure and a second transmission structure. The servo motor is connected to the first link and the second link via the first transmission structure, and the servo motor is connected to the sternum via the second transmission structure.

[0013] The second transmission structure is a crank-slider mechanism.

[0014] Optionally, in one specific embodiment, the system further includes an abdominal airbag assembly;

[0015] The abdominal airbag assembly includes an airbag, an air pump, an exhaust valve, a proportional solenoid valve, and a pressure sensor; the exhaust valve is disposed on the airbag, the pressure sensor is disposed on the inner wall of the airbag, the air pump is connected to the airbag through an air tube, and the proportional solenoid valve is disposed on the air tube.

[0016] Secondly, embodiments of this application provide a method for simulating human respiration based on the aforementioned human thoracic cavity simulation system, comprising:

[0017] Based on the initial settings input by the user, the controller determines the simulation operation parameters in the breathing simulation and sends a start command to the human breathing simulation system to drive the human breathing simulation system to perform breathing simulation based on the simulation operation parameters; the simulation operation parameters include the length of the breathing cycle;

[0018] During the breathing simulation, the crank angle, the actual thrust at the current moment, and the first running time are acquired in real time. Based on the first running time and the length of the breathing cycle, the breathing stage at the current moment within the breathing cycle is determined.

[0019] Based on the current breathing stage, the actual thrust, the first running time, and the crank angle, the driving torque of the servo motor is obtained and sent to the servo motor so that the servo motor drives the thoracic cavity structure model to perform breathing simulation.

[0020] Optionally, in one specific embodiment, the system further includes: an abdominal airbag assembly; the abdominal airbag assembly includes an airbag, an air pump, an exhaust valve, a proportional solenoid valve, and a pressure sensor;

[0021] The simulated breathing parameters also include: peak thrust, crank radius, and initial air pump flow rate;

[0022] Then, based on the initial settings input by the user, the controller determines the simulation parameters in the respiratory simulation, including:

[0023] The controller determines the length of the respiratory cycle based on the target respiratory rate input by the user; the length of the respiratory cycle is the reciprocal of the respiratory rate.

[0024] The peak thrust is determined based on the maximum thrust and the thrust intensity ratio input by the user; the peak thrust is the product of the maximum thrust and the thrust intensity ratio.

[0025] The crank radius is determined based on the chest cavity amplitude input by the user; the crank radius is half of the chest cavity amplitude.

[0026] The air pump flow rate is determined based on the maximum air pump flow rate and the flow intensity ratio input by the user; the initial air pump flow rate is the product of the maximum air pump flow rate and the flow intensity ratio.

[0027] Optionally, in one specific embodiment, the breathing cycle includes an inhalation phase, an exhalation phase, and a pause phase performed sequentially;

[0028] Then, based on the current breathing stage, the actual thrust, the first running time, and the crank angle, the driving torque of the servo motor is obtained and sent to the servo motor so that the servo motor drives the thoracic cavity structure model to perform breathing simulation, including:

[0029] When the current breathing phase is the inhalation phase, the target thrust required at the current moment is obtained based on the first running time and the peak thrust; and the driving torque of the servo motor is obtained based on the target thrust, the actual thrust, the crank angle and the pre-set PID control algorithm, and the driving torque is sent to the servo motor.

[0030] If the current breathing phase is the exhalation phase, a stop command is sent to the servo motor to stop the servo motor from working.

[0031] If the current breathing phase is a pause phase, a braking command is sent to the servo motor to cause the servo motor to brake.

[0032] Optionally, in one specific embodiment, the inhalation phase includes: initial inhalation, middle inhalation, and final inhalation;

[0033] Then, based on the first running time and peak thrust, the target thrust required at the current moment is obtained, including:

[0034] Based on the first running time and the length of the respiratory cycle, determine the second running time within the inspiratory phase at the current moment;

[0035] Based on the second running time and the peak thrust, and a pre-set formula (Formula 1), the target thrust required at the current moment is obtained; the formula (Formula 1) is:

[0036]

[0037] Among them, F peak Let F(t) be the peak thrust, t be the second running time, F(t) be the actual thrust required at the current moment, and T be the peak thrust. in This represents the length of the inspiratory phase, obtained from the length of the respiratory cycle.

[0038] Optionally, in one specific embodiment, the method further includes:

[0039] During the respiratory simulation, the controller determines the third running time within the respiratory cycle at the current moment based on the first running time and the cycle length.

[0040] The target pressure at the current moment is obtained in real time based on the crank angle, the third running time, and the crank radius;

[0041] Based on the target pressure and the actual pressure collected in advance at the previous moment, a first adjustment command is sent to the abdominal airbag assembly to cause the air pump, the exhaust valve and the proportional solenoid valve to drive the airbag to perform a breathing simulation.

[0042] Optionally, in one specific embodiment, the method further includes:

[0043] The controller generates valve control commands in real time based on the length of the breathing cycle and the crank angle to control the opening / closing of the exhaust valve and the proportional regulating valve.

[0044] Optionally, in one specific embodiment, the method further includes:

[0045] The controller collects the actual pressure value sent by the pressure sensor in real time, and determines whether the error exceeds the preset error threshold based on the actual pressure value and the target pressure.

[0046] When the error exceeds the limit, a second adjustment command is sent to the abdominal airbag assembly based on the error, so that the air pump, the exhaust valve and the proportional solenoid valve drive the airbag to perform a breathing simulation.

[0047] (III) Beneficial Effects

[0048] This application provides a human respiratory simulation system, which serves as a calibration device for non-contact respiratory parameter measurement, avoiding interference from the external environment and improving the accuracy of the test results.

[0049] By using a single servo motor to synchronously drive the sternum and all the rib supports, the rise and fall of the chest cavity and the expansion of the ribs are strictly synchronized, ensuring the accuracy of the respiratory simulation. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the thoracic cavity structure model provided in the embodiments of this application;

[0051] Figure 2 This is a schematic diagram of a crank-slider mechanism provided in an embodiment of this application;

[0052] Figure 3 A flowchart illustrating the human breathing simulation method provided in this application embodiment;

[0053] Figure 4 This is a schematic diagram of the servo motor torque adjustment process provided in an embodiment of this application;

[0054] Figure 5 This is a schematic diagram of the airbag adjustment process provided in an embodiment of this application. Detailed Implementation

[0055] To better explain and facilitate understanding of this application, the following detailed description of the application is provided in conjunction with the accompanying drawings and specific embodiments.

[0056] Respiratory parameter measurement methods are mainly divided into contact and non-contact measurements. Currently, the more mature and successfully applied multidimensional contact measurement methods in clinical practice include respiratory airflow detection, photoplethysmography (PPG), impedance respiration monitoring, and transformer detection. However, contact measurements are typically wearable devices, which are invasive and often inconvenient for subjects. Furthermore, contact measurements require high levels of safety and technical expertise, making them unsuitable for casual monitoring in daily life. Non-contact measurement methods, on the other hand, avoid contact with the user and allow for remote measurement; therefore, non-contact measurement represents the future direction of respiratory measurement technology. However, due to deficiencies in robustness and accuracy, they have not been widely adopted in clinical practice or routine health monitoring. Therefore, calibrating the accuracy of non-contact measurements is an essential step towards clinical application.

[0057] Currently, comparing the results of non-contact measurements with those from commercial monitoring instruments or manual counting is a common practice.

[0058] However, while manual counting of respiratory expansion and contraction is highly accurate, it is not conducive to automated integration. Current commercial monitoring instruments mostly detect changes in chest cavity expansion and contraction during respiration using methods such as radar ranging, optical flow identification, and microwave ranging. These methods are easily affected by the environment and struggle to effectively distinguish interfering movements, impacting measurement accuracy. Furthermore, external environmental factors such as electromagnetic signals, fiber optic changes, and object movement can interfere with the propagation and reception of radar, optical flow, or microwave signals, leading to measurement errors and affecting the accuracy of respiratory status assessment.

[0059] The human respiratory simulation system proposed in this application serves as a calibration device for non-contact respiratory parameter measurement, avoiding interference from the external environment and improving the accuracy of the test results. Furthermore, by synchronously driving the sternum and all rib supports with a single servo motor, strict synchronization between chest cavity rise and fall and rib expansion is achieved, ensuring the accuracy of the respiratory simulation.

[0060] To better understand the above technical solutions, exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application can be understood more clearly and thoroughly, and that the scope of this application can be fully conveyed to those skilled in the art.

[0061] This application provides a human breathing simulation system, including: a thoracic cavity structure model and a thoracic cavity drive assembly. The thoracic cavity drive assembly has three drive shafts that output linear motion driven by the same servo motor, and the three drive shafts maintain synchronous motion.

[0062] The thoracic cavity structure model has a first link and a second link on both sides of the sternum, and both the first link and the second link are connected to the ends of all the rib supports on the same side.

[0063] The three drive shafts that output linear motion, driven by the same servo motor, are connected to the first link, the second link, and the sternum, respectively, to push the sternum and all the rib supports to expand.

[0064] Furthermore, the system also includes an abdominal pneumatic bladder assembly;

[0065] The abdominal airbag assembly includes an airbag, an air pump, an exhaust valve, a proportional solenoid valve, and a pressure sensor; the exhaust valve is located on the airbag, the pressure sensor is located on the inner wall of the airbag, the air pump is connected to the airbag through an air tube, and the proportional solenoid valve is located on the air tube.

[0066] Optionally, in one specific embodiment, the thoracic cavity drive assembly includes a first transmission structure and a second transmission structure. The servo motor is connected to the first connecting rod and the second connecting rod via the first transmission structure, and the servo motor is connected to the sternum via the second transmission structure. The second transmission structure is a crank-slider mechanism.

[0067] Specifically, the thoracic cavity drive assembly includes a servo motor, a crank, a branch connecting rod, and a slider. The crank and the branch connecting rod are both mounted on the main drive shaft of the servo motor, and the crank is locked to the main drive shaft. The branch connecting rods are symmetrically mounted on the main drive shaft. The two ends of the branch connecting rods are respectively provided with a first connecting rod and a second connecting rod. The output shaft end of the crank is provided with a third connecting rod, and the crank is connected to the slider through the third connecting rod. The slider and all the first connecting rods are connected to the sternum of the thoracic cavity structure model.

[0068] The abdominal airbag assembly includes an airbag, an air pump, an exhaust valve, a proportional solenoid valve, and a pressure sensor; the exhaust valve is located on the airbag, the pressure sensor is located on the inner wall of the airbag, the air pump is connected to the airbag through an air tube, and the proportional solenoid valve is located on the air tube; the airbag is placed on the thoracic cavity structure model.

[0069] Thoracic cavity structure model, such as Figure 1 As shown, it includes a thoracic shell, a spinal model and multiple rib supports mounted on the thoracic shell; all rib supports are symmetrically arranged on both sides of the spinal model, and each rib support is connected to the spinal model by a hinge.

[0070] The spine model is mounted on a first connecting rod on both sides, and the ends of all rib supports on the same side are fixedly connected to the first or second connecting rod on the same side by screws; the first and second connecting rods are respectively mounted on the two ends of the branch connecting rod via universal joints; that is, the first transmission structure is realized through the branch connecting rod.

[0071] The crank is securely locked to the main drive shaft by a screw and nut;

[0072] The sternum is fixedly connected to the slider;

[0073] The air bladder is fixed to the outer shell of the thoracic cavity and located below the sternum and rib cage.

[0074] Optionally, in one specific embodiment, a slider interface is provided at the center of the sternum of the thoracic cavity shell, and the slider is rigidly connected to the slider interface; the slider is connected to the second link through a ball joint; the airbag is attached to the thoracic cavity shell by Velcro.

[0075] Specifically, the outer shell of the thoracic cavity is made of silicone material (Shore hardness 20A, thickness 3mm) to simulate the elasticity of soft tissue, and each rib support is a carbon fiber rib support (diameter 8mm, radius of curvature 150mm), which is connected to the polycarbonate spine model through hinges.

[0076] The thoracic drive assembly includes a crank-slider mechanism, the structure of which is as follows: Figure 2 As shown, the crank-slider mechanism is a servo motor-driven adjustable crank that pushes the slider to move linearly (0-50mm) via a connecting rod. The crank is connected to the main drive shaft of the servo motor by a threaded rod and a tightening nut, which can be adjusted and then locked.

[0077] Furthermore, to achieve synchronized movement of the chest cavity's rise and fall with the expansion / contraction of the ribs, the crank-slider mechanism and the rib support need to be connected via connecting rods to ensure coordination between the two sets of movements under a single motor drive. Specifically, branch connecting rods (spring steel, stiffness 500 N / m) are symmetrically installed on both sides of the main drive shaft, with their ends connected to the first connecting rod via universal joints.

[0078] The abdominal airbag assembly requires embedding an airbag (0.5L volume, 5kPa burst pressure) into a stretchable abdominal model made of silicone; it is regulated and monitored by a micro air pump (flow rate 0-10L / min), a proportional solenoid valve (response time <10ms), and a pressure sensor (accuracy ±0.1kPa).

[0079] Furthermore, there are 6 pairs of movable rib supports, with each rib support end connected to a transverse link (i.e., the first link). Each transverse link is made of aluminum alloy with a diameter of 10mm, and the proximal end is connected to the spinal model via a hinge. A slider interface is installed in the center of the sternal region and rigidly connected to the drive mechanism.

[0080] The human breathing simulation system provided in the embodiments of this application achieves strict synchronization of chest cavity rise and fall and rib expansion by driving a crank slider and a branch connecting rod with a single motor (improving mechanism efficiency by 40%); and in conjunction with the abdominal air pressure system, achieves multi-dimensional synchronous motion of chest cavity rise and fall, rib expansion / contraction and abdominal rise and fall.

[0081] Furthermore, the working principle of the human respiratory model system provided in this embodiment is as follows:

[0082] First, the breathing frequency is adjusted by regulating the speed of the servo motor, which controls the motion cycle of the crank-slider mechanism. The relationship between the breathing frequency f (Hz) and the electronic speed n (r / min) is: f = n / 60; the servo motor adopts a vector control mode, supporting continuous adjustment from 0.1-2Hz (the normal breathing frequency of a person is 0.2-0.4Hz).

[0083] Secondly, the rotational motion of the motor is converted into the linear reciprocating motion of the slider through the crank and the second connecting rod. The slider stroke can be directly controlled by adjusting the crank radius r: that is, S = 2r, where r is the crank radius. The stroke directly corresponds to the amplitude of chest cavity movement and supports continuous adjustment from 0-50mm (normal chest cavity displacement is about 1-20mm).

[0084] The rib rotation angle α is determined by the branch link displacement and the first link length L, i.e., α = arcsin(d y / L), d y The vertical displacement of the branch link is proportional to the S-shape formed by the slider. L is the length of the first link, which is preset according to the average spacing between human ribs, usually 150-200mm. By replacing the first link with different lengths, asymmetrical breathing under pathological conditions (such as pneumothorax, rib fractures) can be simulated. In addition, by adjusting the external rotation angle of the ribs and the movement trajectory of the chest cavity, different breathing patterns (such as thoracic breathing and abdominal breathing) can also be simulated.

[0085] Furthermore, during abdominal amplitude regulation, the relationship between the gas expansion volume V and the internal pressure P is approximately: V = k p ×(P target -P ext ), where kp is the airbag elasticity coefficient, P ext The external atmospheric pressure is used. The amplitude of abdominal movement is related to the airbag inflation volume, which can be adjusted by setting P. targe Adjustments can be made, thus the amplitude can be converted into the target pressure P based on the airbag characteristic curve. targe .

[0086] Furthermore, in respiratory intensity regulation, respiratory intensity in clinical medicine usually refers to the mechanical output generated when the respiratory muscles contract, that is, the force that the diaphragm and external intercostal muscles exert to expand the thoracic cavity. To adapt to different testing scenarios (such as calm breathing, deep breathing, and pathological breathing), respiratory intensity needs to be normalized to a percentage parameter. Generally, the average intensity of calm breathing in healthy adults is set to 50%, and the maximum exertional breathing intensity is set to 100%. Respiratory intensity is directly proportional to the mechanical efficiency of thoracic cavity movement per unit time, that is: I = k·F·v = k·F·(2πfS);

[0087] According to the Clinical Guidelines for Respiratory Mechanics (ATS / ERS standards), the diaphragmatic contraction force during quiet breathing in healthy adults is approximately 5–10 N, and the maximum forceful inhalation can reach 30–50 N. This simulator mainly controls the thrust F of the crank-slider mechanism by adjusting the output torque Tmotor of the servo motor, thereby achieving the target thrust in the thoracic cavity: F = Tmotor·μ·sinθ / r. The greater the thrust F, the higher the breathing intensity.

[0088] In the abdominal cuff assembly, breathing intensity is reflected in the rate of pressure change (inflation / deflation rate) and peak pressure. The inflation / deflation rate of the cuff is controlled by adjusting the air pump flow rate Q (in L / min) and the solenoid valve opening.

[0089]

[0090] In this way, pressure changes can be accelerated by increasing Q and the opening of the solenoid valve, thereby simulating high-intensity breathing; a higher P can be directly set. target Peak pressure is adjusted to simulate the strong contraction of abdominal muscles during deep breathing.

[0091] Furthermore, the human breathing simulation system provided in this application embodiment also includes a controller, which is electrically connected to the servo motor, the exhaust valve, the proportional solenoid valve and the pressure sensor respectively; used to control the thoracic cavity drive assembly and the abdominal airbag assembly to drive the thoracic cavity structure model to perform breathing simulation.

[0092] The controller uses the Huichuan Easy302 PLC, which integrates analog input / output modules. Its sensing unit and encoder (17-bit resolution) are used to monitor the crank angle. In addition, the pressure sensor (range 0-50N, accuracy ±0.5%) monitors the internal pressure of the airbag in real time and feeds it back to the controller to form a closed loop.

[0093] The servo motor in the thoracic cavity drive assembly is controlled by torque, specifically:

[0094]

[0095] Among them, F target The real-time output force of the drive motor is determined by the breathing intensity used; μ is the mechanical efficiency.

[0096] The strategy for synchronized and coordinated movement of the airbags is as follows: the PLC receives encoder pulse signals and triggers abdominal air pressure control, that is:

[0097]

[0098] Among them, K qβ is the proportional parameter between the airbag inflation height and pressure, determined by the airbag characteristic curve; β is the proportional factor between the abdominal rise and fall amplitude and the chest cavity amplitude under different breathing modes. The phase difference between chest and abdominal movements (adjustable range 0-90°).

[0099] The human breathing simulation system provided in this embodiment achieves strict synchronization between chest cavity rise and fall and rib expansion by driving a crank slider and a branch connecting rod with a single motor (improving mechanism efficiency by 40%); in conjunction with the abdominal air pressure system, it achieves multi-dimensional synchronous motion of chest cavity rise and fall, rib expansion / contraction and abdominal rise and fall.

[0100] Moreover, it can be used as a calibration device for non-contact respiratory parameter measurement methods, making up for the limitations of electrical impedance thoracic simulators.

[0101] In addition, such as Figure 3 As shown, this application embodiment provides a method for simulating human respiration based on the above-described human respiration simulation system and a human chest cavity simulation system, comprising:

[0102] Based on the initial settings input by the user, the controller determines the simulation parameters in the breathing simulation and sends a start command to the human breathing simulation system to drive the human breathing simulation system to perform breathing simulation based on the simulation parameters; the simulation parameters include the length of the breathing cycle;

[0103] During the breathing simulation process, real-time feedback and adjustment of the servo motor are required. The adjustment process of the servo motor is as follows: Figure 4 As shown, it includes:

[0104] S11. Real-time acquisition of crank angle, actual thrust at the current moment and first running time, and determination of the breathing stage within the breathing cycle at the current moment based on the first running time and breathing cycle length;

[0105] S12. Based on the current breathing stage, actual thrust, first running time, and crank angle, obtain the driving torque of the servo motor and send it to the servo motor so that the servo motor drives the thoracic cavity structure model to perform breathing simulation.

[0106] The human respiratory simulation method provided in this embodiment is used for the accuracy calibration and performance evaluation of respiratory parameter measurement devices, and can provide high output accuracy and a wide adjustment range. This device, through a composite mechanical structure and a multimodal control system, achieves bio-simulation of chest cavity, rib, and abdominal movements, and provides quantifiable and adjustable respiratory parameter benchmarks. By comparing the deviations between the measurement results of non-contact methods and the device's set parameters, accurate calibration of the non-contact measurement method is achieved.

[0107] Optionally, in one specific embodiment, the simulated breathing parameters further include: peak thrust, crank radius, and initial air pump flow rate;

[0108] Then, based on the initial settings input by the user, the controller determines the simulation parameters in the respiratory simulation, including:

[0109] The controller determines the respiratory cycle length based on the target respiratory rate input by the user; the respiratory cycle length is the reciprocal of the respiratory rate.

[0110] The peak thrust is determined based on the user-input maximum thrust and thrust strength ratio; the peak thrust is the product of the maximum thrust and the thrust strength ratio.

[0111] The crank radius is determined based on the user-inputted chest cavity amplitude; the crank radius is half of the chest cavity amplitude.

[0112] The pump flow rate is determined based on the user-input maximum pump flow rate and flow intensity ratio; the initial pump flow rate is the product of the maximum pump flow rate and the flow intensity ratio.

[0113] Specifically, the first step is to set the parameters, which is done by the user through the touchscreen to calibrate the parameters.

[0114] First, set the breathing parameters, specifically the frequency: input the target breathing frequency f (0.2Hz) via the touchscreen, and the PLC automatically calculates the respiratory cycle T and the time allocation for each stage: T = 1 / f, where T is the length of the respiratory cycle. Conventionally, the inspiratory stage T is usually preset. in =0.3T, T during the inhalation phase ex =0.3T, pause phase T stop =0.4T.

[0115] Secondly, the amplitude setting, that is, manually adjusting the length r of the crank radius, which can be based on the chest amplitude S during calm breathing. chest The chest cavity amplitude is typically set to 20mm.

[0116] Furthermore, set the peak thrust, i.e., the thoracic cavity strength setting: input the thrust strength ratio I1 and the maximum thrust F. max Calculate the corresponding target peak thrust F peak :

[0117] F peak =F max ·I1(F max (Generally set to 50N);

[0118] Furthermore, the air pump flow rate is determined by inputting the maximum air pump flow rate and the flow intensity ratio, i.e.: Q = Q max ·I2(Q max(Generally set to 10L / min).

[0119] Additionally, the target abdominal bulge height needs to be calculated based on the pre-set abdominal breathing ratio coefficient γ (default 0.6), i.e., S1 = γ·S chest ;

[0120] Convert the target bulge height into target pressure P1, where P1 = K q ·S1(K q It is generally set to 0.1 kPa / mm.

[0121] This embodiment provides a foundation for the stable operation of the human breathing simulation system by pre-setting the initial parameters, ensuring that subsequent breathing simulations meet real-world requirements.

[0122] Optionally, in one specific embodiment, the respiratory cycle includes an inhalation phase, an exhalation phase, and a pause phase performed sequentially;

[0123] Then, based on the current breathing stage, actual thrust, first running time, and crank angle, the driving torque of the servo motor is obtained and sent to the servo motor so that the servo motor drives the thoracic cavity structure model to perform breathing simulation, including:

[0124] When the current breathing phase is the inhalation phase, the target thrust required at the current moment is obtained based on the first running time and the peak thrust; and the driving torque of the servo motor is obtained based on the target thrust, the actual thrust, the crank angle and the pre-set PID control algorithm, and the driving torque is sent to the servo motor.

[0125] If the current breathing phase is the exhalation phase, a stop command is sent to the servo motor to stop the servo motor from working.

[0126] If the current breathing phase is a pause phase, a braking command is sent to the servo motor to make the servo motor brake.

[0127] Furthermore, the inhalation phase includes: the initial inhalation, the middle inhalation, and the final inhalation.

[0128] Then, based on the first running time and peak thrust, the target thrust required at the current moment is obtained, including:

[0129] Based on the first run time and the length of the respiratory cycle, determine the second run time within the inspiratory phase at the current moment;

[0130] Based on the second running time and peak thrust, and using the pre-set Formula 1, the target thrust required at the current moment is obtained; Formula 1 is:

[0131]

[0132] Among them, F peak Let F(t) be the peak thrust, t be the second running time, F(t) be the actual thrust required at the current moment, and T be the peak thrust. in This represents the length of the inspiratory phase, obtained from the length of the respiratory cycle.

[0133] Specifically, during normal breathing, the thoracic thrust during inhalation is not completely uniform and constant; its mechanical properties are characterized by the following:

[0134] During the initial stage of inspiration (0%–30% inspiration): the diaphragm and external intercostal muscles contract rapidly, the chest cavity expands at a relatively high acceleration, and the thrust rises rapidly to its peak. At this time, it is necessary to overcome the viscous resistance and inertial resistance of the lung tissue, and the thrust exhibits a non-linear growth.

[0135] Mid-inspiratory phase (30%–70% inspiratory phase): The elastic recoil force of the lungs gradually increases, balancing with the contractile force of the respiratory muscles, and the thrust tends to stabilize (approximately a plateau phase).

[0136] Late inspiratory phase (70%–100% inspiratory phase): The lungs approach their maximum volume, elastic resistance increases significantly, and the respiratory muscles need to exert extra force to maintain expansion, causing the thrust to rise again.

[0137] Based on the respiratory muscle compression characteristics under actual breathing conditions, a segmented formula for the thoracic cavity actuation mechanism is constructed:

[0138]

[0139] This embodiment can perform a more realistic breathing simulation by segmenting the inhalation phase and calculating the required target thrust in real time.

[0140] Specifically, in one embodiment, based on the target thrust, actual thrust, crank angle, and a pre-set PID control algorithm, the driving torque of the servo motor is obtained, and the driving torque is sent to the servo motor, including:

[0141] Based on the required thoracic thrust (i.e., the actual thrust required at the current moment as calculated above), the driving torque of the servo motor is precisely controlled, and the driving torque is calculated using the following formula:

[0142]

[0143] Where T1 is the driving torque, K p K i K dThese are the pre-set proportional coefficient, integral coefficient, and differential coefficient, respectively. dM / dt is the change in error between the target thrust and the actual thrust over time, M is the error between the target thrust and the actual thrust, r is the crank radius, μ is the mechanical efficiency, F(t) is the target thrust, and θ is the crank angle.

[0144] This embodiment dynamically changes the thrust required for thoracic cavity expansion during inhalation over time (e.g., gradually increasing from zero thrust to a peak value, then maintaining or decreasing it). Based on the target thrust setting method of "first running time + peak thrust," it accurately matches the physiological and mechanical characteristics of human inhalation (e.g., increasing thrust in the early stage of inhalation and maintaining a stable thrust in the middle stage), avoiding the problems of insufficient thrust leading to inadequate expansion or excessive thrust causing over-simulation. Furthermore, by using a PID algorithm to dynamically adjust the actual thrust (feedback value) and target thrust (set value), as well as the crank angle (position feedback), errors caused by factors such as mechanical transmission clearance and frictional resistance can be compensated in real time. For example, when the actual thrust is less than the target value, the PID algorithm increases the driving torque; when the crank angle deviates from the preset trajectory, the output is adjusted in advance through the differential element to ensure the trajectory accuracy and thrust stability of the thoracic cavity movement. Furthermore, the thrust change during the inhalation phase is controlled gradually over time (rather than abruptly), and the integral element of the PID controller eliminates accumulated errors. This avoids impacts or vibrations to the chest cavity simulation mechanism caused by thrust fluctuations, ensuring the physiological realism of the breathing simulation (the human inhalation process is continuous and smooth) and reducing the risk of wear on mechanical components due to excessive instantaneous force. Finally, when the user adjusts breathing parameters (such as respiratory rate and inhalation time percentage), the target thrust calculation method based on "running time" can quickly adapt to the new time allocation scheme, while the PID algorithm can automatically adapt to the dynamic characteristics under different parameters (such as inertia changes corresponding to different respiratory rates). This eliminates the need for frequent readjustment of the mechanical structure and improves the system's adaptability to diverse breathing simulation scenarios.

[0145] Optionally, in a specific embodiment, to maintain the realism of the breathing simulation, abdominal breathing simulation is introduced during the breathing simulation process. This is achieved by real-time adjustment of the airbag, as described in the real-time airbag adjustment process. Figure 5 As shown, it includes:

[0146] S21. The controller determines the third running time within the respiratory cycle at the current moment based on the first running time and the cycle length;

[0147] S22. Obtain the target pressure at the current moment based on the crank angle, third running time, and crank radius;

[0148] S23. Based on the target pressure and the actual pressure collected in advance at the previous moment, send the first adjustment command to the abdominal airbag assembly so that the air pump, exhaust valve and proportional solenoid valve drive the airbag to perform respiratory simulation.

[0149] Furthermore, the controller generates valve control commands in real time based on the respiratory cycle length T and crank angle θ to control the opening / closing of the exhaust valve and proportional regulating valve.

[0150] Furthermore, the controller collects the actual pressure value sent by the pressure sensor in real time, and determines whether the error exceeds the preset error threshold based on the actual pressure value and the target pressure.

[0151] When the error exceeds the limit, a second adjustment command is sent to the abdominal airbag assembly based on the error, so that the air pump, exhaust valve and proportional solenoid valve drive the airbag to perform a breathing simulation.

[0152] Specifically, the encoder monitors the crank angle in real time and triggers the abdominal airbag assembly when the third running time t1 = 0.05T. When the crank angle is 2πt1 / T (i.e., the lowest point of the slider), the exhaust valve is opened; when the crank angle is π-2πt1 / T (i.e., the highest point of the slider), the proportional adjustment valve and the air pump are opened.

[0153] Phase difference compensation: The trigger angle offset of the charging / discharging valve (range 0-90°) is adjusted by the PLC program to match the delay of chest and abdominal movement.

[0154] During resting respiration, the ratio of real-time abdominal pressure P1 to thoracic displacement is as follows:

[0155]

[0156] Where x1 is the displacement of the thoracic cavity, x1=r(1-cosθ), and θ is the crank angle.

[0157] During human respiration, abdominal and thoracic movements are not independent but are related in terms of timing and amplitude (e.g., the abdomen may bulge while the chest expands during inhalation and contracts simultaneously during exhalation). In this embodiment, the third running time (relative time within the respiratory cycle) is used to determine the current stage. The crank angle and radius directly reflect the real-time displacement of the chest cavity. The target pressure is dynamically calculated based on these parameters, ensuring that the pressure changes in the abdominal air sac match the physiological laws of the human body in terms of timing (e.g., synchronous pressure increase at the beginning of inhalation and synchronous pressure decrease at the beginning of exhalation) and amplitude (the greater the chest expansion, the more significant the increase in abdominal pressure), thus improving the realism of the respiratory simulation. The comparison and feedback between the target pressure and the actual pressure at the previous moment adjusts the air pump, exhaust valve, and proportional solenoid valve in real time. Through this instant feedback adjustment method, pressure deviations caused by factors such as air sac leakage and air pump flow fluctuations can be quickly compensated, avoiding pressure lag or overshoot and ensuring that the abdominal pressure strictly follows the target value.

[0158] This embodiment achieves physiological coordination, precise control, and flexible adaptation between abdominal airbag movement and thoracic cavity movement through multi-parameter linkage and feedback adjustment, which is an important guarantee for the realism and reliability of respiratory simulation.

[0159] Specifically, the human respiratory simulation system provided in this embodiment, as a calibration device for non-contact respiratory parameter measurement, avoids interference from the external environment and improves the accuracy of the test results;

[0160] Among them, a single servo motor drives the crank and the branch connecting rod to achieve strict synchronization between chest cavity rise and fall and rib expansion; while the abdominal airbag assembly is used to coordinate abdominal air pressure to achieve multi-dimensional synchronous movement of chest cavity rise and fall, rib expansion / contraction and abdominal rise and fall.

[0161] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0162] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0163] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0164] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0165] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A human breathing simulation system, characterized in that, include: The thoracic cavity structure model and the thoracic cavity drive assembly have three drive shafts that output linear motion driven by the same servo motor, and the three drive shafts maintain synchronous motion. The thoracic cavity structure model has a first link and a second link on both sides of the sternum, and both the first link and the second link are connected to the ends of all the rib supports on the same side. The three drive shafts that output linear motion, driven by the same servo motor, are connected to the first link, the second link, and the sternum, respectively, to push the sternum and all the rib supports to expand.

2. The human respiratory simulation system according to claim 1, characterized in that, The thoracic drive assembly includes a first transmission structure and a second transmission structure. The servo motor is connected to the first link and the second link through the first transmission structure, and the servo motor is connected to the sternum through the second transmission structure. The second transmission structure is a crank-slider mechanism.

3. The human respiratory simulation system according to claim 1, characterized in that, The system also includes an abdominal airbag assembly; The abdominal airbag assembly includes an airbag, an air pump, an exhaust valve, a proportional solenoid valve, and a pressure sensor; the exhaust valve is disposed on the airbag, the pressure sensor is disposed on the inner wall of the airbag, the air pump is connected to the airbag through an air tube, and the proportional solenoid valve is disposed on the air tube.

4. A method for simulating human respiration based on the human thoracic cavity simulation system according to any one of claims 1 to 3, characterized in that, include: Based on the initial settings input by the user, the controller determines the simulation operation parameters in the breathing simulation and sends a start command to the human breathing simulation system to drive the human breathing simulation system to perform breathing simulation based on the simulation operation parameters; the simulation operation parameters include the length of the breathing cycle; During the breathing simulation, the crank angle, the actual thrust at the current moment, and the first running time are acquired in real time. Based on the first running time and the length of the breathing cycle, the breathing stage at the current moment within the breathing cycle is determined. Based on the current breathing stage, the actual thrust, the first running time, and the crank angle, the driving torque of the servo motor is obtained and sent to the servo motor so that the servo motor drives the thoracic cavity structure model to perform breathing simulation.

5. The human breathing simulation method according to claim 4, characterized in that, The system also includes: an abdominal airbag assembly; the abdominal airbag assembly includes an airbag, an air pump, an exhaust valve, a proportional solenoid valve, and a pressure sensor; The simulated breathing parameters also include: peak thrust, crank radius, and initial air pump flow rate; Then, based on the initial settings input by the user, the controller determines the simulation parameters in the respiratory simulation, including: The controller determines the length of the respiratory cycle based on the target respiratory rate input by the user; the length of the respiratory cycle is the reciprocal of the respiratory rate. The peak thrust is determined based on the maximum thrust and the thrust intensity ratio input by the user; the peak thrust is the product of the maximum thrust and the thrust intensity ratio. The crank radius is determined based on the chest cavity amplitude input by the user; the crank radius is half of the chest cavity amplitude. The air pump flow rate is determined based on the maximum air pump flow rate and the flow intensity ratio input by the user; the initial air pump flow rate is the product of the maximum air pump flow rate and the flow intensity ratio.

6. The human breathing simulation method according to claim 5, characterized in that, The respiratory cycle includes an inhalation phase, an exhalation phase, and a pause phase, which are performed sequentially. Then, based on the current breathing stage, the actual thrust, the first running time, and the crank angle, the driving torque of the servo motor is obtained and sent to the servo motor so that the servo motor drives the thoracic cavity structure model to perform breathing simulation, including: When the current breathing phase is the inhalation phase, the target thrust required at the current moment is obtained based on the first running time and the peak thrust; and the driving torque of the servo motor is obtained based on the target thrust, the actual thrust, the crank angle and the pre-set PID control algorithm, and the driving torque is sent to the servo motor. If the current breathing phase is the exhalation phase, a stop command is sent to the servo motor to stop the servo motor from working. If the current breathing phase is a pause phase, a braking command is sent to the servo motor to cause the servo motor to brake.

7. The human breathing simulation method according to claim 6, characterized in that, The inhalation phase includes: the initial inhalation phase, the middle inhalation phase, and the final inhalation phase; Then, based on the first running time and peak thrust, the target thrust required at the current moment is obtained, including: Based on the first running time and the length of the respiratory cycle, determine the second running time within the inspiratory phase at the current moment; Based on the second running time and the peak thrust, and a pre-set formula (Formula 1), the target thrust required at the current moment is obtained; the formula (Formula 1) is: Among them, F peak Let F(t) be the peak thrust, t be the second running time, F(t) be the actual thrust required at the current moment, and T be the peak thrust. in This represents the length of the inspiratory phase, obtained from the length of the respiratory cycle.

8. The human breathing simulation method according to claim 5, characterized in that, The method further includes: During the respiratory simulation, the controller determines the third running time within the respiratory cycle at the current moment based on the first running time and the cycle length. The target pressure at the current moment is obtained in real time based on the crank angle, the third running time, and the crank radius; Based on the target pressure and the actual pressure collected in advance at the previous moment, a first adjustment command is sent to the abdominal airbag assembly to cause the air pump, the exhaust valve and the proportional solenoid valve to drive the airbag to perform a breathing simulation.

9. The human breathing simulation method according to claim 4, characterized in that, The method further includes: The controller generates valve control commands in real time based on the length of the breathing cycle and the crank angle to control the opening / closing of the exhaust valve and the proportional regulating valve.

10. The human breathing simulation method according to claim 9, characterized in that, The method further includes: The controller collects the actual pressure value sent by the pressure sensor in real time, and determines whether the error exceeds the preset error threshold based on the actual pressure value and the target pressure. When the error exceeds the limit, a second adjustment command is sent to the abdominal airbag assembly based on the error, so that the air pump, the exhaust valve and the proportional solenoid valve drive the airbag to perform a breathing simulation.

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