Method and device for oxygen mixing control for non-invasive respiratory devices

Abstract

This invention provides a method and device for oxygen mixing control in non-invasive respiratory devices. The method includes: setting a target oxygen concentration in the mixed gas and calculating a target oxygen flow rate; acquiring real-time oxygen flow rate and obtaining an oxygen flow rate deviation signal between the real-time oxygen flow rate and the target oxygen flow rate; outputting an oxygen flow rate control quantity based on the relationship between the oxygen flow rate deviation signal and a preset oxygen flow rate deviation threshold to adjust the real-time oxygen flow rate; and, based on the aforementioned steps, acquiring the actual value of the mixed gas oxygen concentration and obtaining an oxygen concentration deviation signal between the actual mixed gas oxygen concentration and the target mixed gas oxygen concentration; and outputting an oxygen concentration control quantity based on the relationship between the oxygen concentration deviation signal and the preset oxygen concentration deviation threshold to correct the target mixed gas oxygen concentration. This invention improves the real-time performance and accuracy of oxygen mixing control.

Description

Technical Field

[0001] This invention relates to the field of medical ventilation technology, specifically to a method and device for oxygen mixing control in non-invasive breathing equipment. Background Technology

[0002] Oxygen therapy is used clinically to correct hypoxia, improve tissue oxygenation, and reduce the work of breathing. Oxygen therapy requires precise control of oxygen concentration; otherwise, it will not achieve the desired therapeutic effect, may lead to oxygen toxicity, endanger the patient's life, and could even result in medical accidents.

[0003] Existing oxygen concentration control technologies can be roughly divided into two types. One type uses oxygen concentration to calculate oxygen flow rate target for closed-loop flow control. This method does not directly measure oxygen concentration and cannot guarantee accurate control of oxygen concentration. The other type uses oxygen concentration sensors for closed-loop control with oxygen concentration as the control target. Since oxygen concentration sensors generally have slow response speed and poor sensitivity, the control is easily affected by the patient's breathing, especially in the case of a mask, which can easily lead to carbon dioxide retention. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a method and device for oxygen mixing control in non-invasive breathing equipment, thereby improving the real-time performance and accuracy of oxygen mixing control.

[0005] The oxygen mixing control method for non-invasive breathing devices includes the following steps:

[0006] S1: Set the target oxygen concentration for the mixed gas, and calculate the target oxygen flow rate based on the target oxygen concentration for the mixed gas:

[0007]

[0008] In the formula: Target oxygen flow rate; Flow mix The flow rate of the mixed gas is the real-time flow rate; O2% is the target oxygen concentration in the mixed gas; Flow Air Real-time airflow;

[0009] S2: Collect real-time oxygen flow rate and obtain the oxygen flow rate deviation signal between the real-time oxygen flow rate and the target oxygen flow rate:

[0010]

[0011] In the formula: e(k) is the oxygen flow rate deviation signal, and k represents the feedback value of the kth acquisition; The real-time oxygen flow rate;

[0012] S3: Output an oxygen flow control quantity based on the relationship between the oxygen flow deviation signal and the preset oxygen flow deviation threshold, so as to adjust the real-time oxygen flow, wherein:

[0013]

[0014] In the formula: u(k) is the oxygen flow control quantity, and k represents the feedback value collected in the kth time; u min u is the preset minimum output value. max K is the preset maximum output. I is the first integral coefficient, and 'a' is the preset oxygen flow rate deviation threshold;

[0015] S4: Based on the execution of S1-S3, collect the actual value of the oxygen concentration of the mixed gas, and obtain the oxygen concentration deviation signal between the actual value of the oxygen concentration of the mixed gas and the target oxygen concentration of the mixed gas:

[0016] e1(k) = O2% - O2RT%

[0017] In the formula: O1(k) is the oxygen concentration deviation signal, k represents the feedback value of the kth acquisition; O2RT% is the actual value of the oxygen concentration of the mixed gas;

[0018] S5: Output an oxygen concentration control quantity based on the relationship between the oxygen concentration deviation signal and the preset oxygen concentration deviation threshold, in order to correct the oxygen concentration of the target mixed gas, wherein:

[0019]

[0020] In the formula: u1(k) is the oxygen concentration control value, k represents the feedback value of the kth acquisition; K p K is the proportionality coefficient. i K is the second integral coefficient. d is the differential coefficient; b is the preset oxygen concentration deviation threshold and b > 0.

[0021] The oxygen mixing control device for non-invasive breathing equipment is based on the oxygen mixing control method, and the oxygen mixing control device includes:

[0022] A mixing chamber having an air inlet, an oxygen inlet, and a mixed gas outlet;

[0023] An air passage, one end of which supplies air in, and the other end is connected to the air inlet of the mixing chamber;

[0024] An oxygen gas path, one end of which supplies oxygen, and the other end which connects to the oxygen inlet of the mixing chamber; and

[0025] An output gas path is provided, with one end connected to the mixed gas outlet of the mixing chamber and the other end connected to the ventilator to output the air and oxygen mixture.

[0026] The air path includes: a fan for adjusting the flow rate of the air path; and an air flow sensor for monitoring the flow rate of the air path; the oxygen path includes: a proportional valve for adjusting the flow rate of the oxygen path; the output path includes: a mixed flow sensor for monitoring the flow rate of the mixed gas; and an oxygen concentration sensor for monitoring the oxygen concentration of the mixed gas.

[0027] The oxygen mixing control device further includes a control unit connected to the air flow sensor, the mixing flow sensor, the oxygen concentration sensor, and the proportional valve, and capable of adjusting the opening of the proportional valve based on the monitoring results of the air flow sensor, the mixing flow sensor, and the oxygen concentration sensor.

[0028] Preferably, the control device includes an input module, a first control module, and a second control module, wherein:

[0029] The input module is used to set the target oxygen concentration in the mixed gas.

[0030] The first control module includes a selection switch, a start-stop control unit, and an integral control unit, wherein: the selection switch can selectively connect the start-stop control unit or the integral control unit to the proportional valve, and the start-stop control unit or the integral control unit is used to output an oxygen flow control quantity based on the monitoring results of the air flow sensor and the mixed flow sensor and the oxygen concentration of the target mixed gas, so as to adjust the opening of the proportional valve;

[0031] The second control module includes a PID control unit, which is used to output an oxygen concentration control quantity based on the difference between the monitoring result of the oxygen concentration sensor and the oxygen concentration of the target mixed gas, so as to correct the oxygen concentration of the target mixed gas.

[0032] Preferably, the selection switch can selectively connect the start-stop control unit or the integral control unit to the proportional valve based on the monitoring results of the air flow sensor and the mixed flow sensor, as well as the target oxygen flow rate. The difference between the monitoring results of the mixed flow sensor and the air flow sensor is the real-time oxygen flow rate, wherein:

[0033] When the absolute value of the difference between the real-time oxygen flow rate and the target oxygen flow rate does not exceed the preset oxygen flow rate deviation threshold, the selection switch connects the integral control unit and the proportional valve.

[0034] When the absolute value of the difference between the real-time oxygen flow rate and the target oxygen flow rate exceeds a preset oxygen flow rate deviation threshold, the selection switch connects the start-stop control unit and the proportional valve.

[0035] Preferably, the expression for the oxygen flow control quantity is:

[0036]

[0037] In the formula: u(k) is the oxygen flow control quantity, and k represents the feedback value collected in the kth time; u min This is the preset minimum output value; u max K is the preset maximum output. I is the first integral coefficient, a is the preset oxygen flow deviation threshold and a > 0; e(k) is the oxygen flow deviation signal, which is the difference between the target oxygen flow and the real-time oxygen flow, and the target oxygen flow is calculated from the oxygen concentration of the target mixed gas.

[0038] Preferably, the expression for the oxygen concentration control quantity is:

[0039]

[0040] In the formula: u1(k) is the oxygen concentration control value, k represents the feedback value of the kth acquisition; K p K is the proportionality coefficient. i K is the second integral coefficient. d is the differential coefficient; b is the preset oxygen concentration deviation threshold and b > 0; e1(k) is the oxygen concentration deviation signal, which is the difference between the target mixed gas oxygen concentration and the actual value of the mixed gas oxygen concentration.

[0041] This invention improves the real-time performance and accuracy of mixed oxygen control by superimposing oxygen concentration feedback control on top of oxygen flow feedback control to form a dual closed-loop control. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the connection relationship of an oxygen mixing control device according to one embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the control logic of a control device according to one embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the control logic of an oxygen mixing control method according to one embodiment of the present invention. Detailed Implementation

[0045] To improve the real-time performance and accuracy of oxygen mixing control, this invention provides an oxygen mixing control method and device for non-invasive ventilation equipment. The oxygen mixing control method includes the following steps:

[0046] S1: Set the target oxygen concentration for the mixed gas, and calculate the target oxygen flow rate based on the target oxygen concentration for the mixed gas:

[0047]

[0048] In the formula: Target oxygen flow rate; Flow mix The flow rate of the mixed gas is the real-time flow rate; O2% is the target oxygen concentration in the mixed gas; Flow Air Target airflow;

[0049] S2: Collect real-time oxygen flow rate and obtain the oxygen flow rate deviation signal between the real-time oxygen flow rate and the target oxygen flow rate:

[0050]

[0051] In the formula: e(k) is the oxygen flow rate deviation signal, and k represents the feedback value of the kth acquisition; The real-time oxygen flow rate;

[0052] S3: Output an oxygen flow control quantity based on the relationship between the oxygen flow deviation signal and the preset oxygen flow deviation threshold, so as to adjust the real-time oxygen flow, wherein:

[0053]

[0054] In the formula: u(k) is the oxygen flow control quantity, and k represents the feedback value collected in the kth time; u min u is the preset minimum output value. max K is the preset maximum output. I , where is the first integral coefficient, 'a' is the preset oxygen flow deviation threshold and 'a>0', and the minimum output, maximum output, first integral coefficient and oxygen flow deviation threshold can be selected with appropriate values ​​according to the characteristics of the respiratory system. This selection process is an empirical method known to those skilled in the art.

[0055] S4: Based on the execution of S1-S3, collect the actual value of the oxygen concentration of the mixed gas, and obtain the oxygen concentration deviation signal between the actual value of the oxygen concentration of the mixed gas and the target oxygen concentration of the mixed gas:

[0056] e1(k) = O2% - O2RT%

[0057] In the formula: e1(k) is the oxygen concentration deviation signal, k represents the feedback value of the kth acquisition; O2RT% is the actual value of the oxygen concentration of the mixed gas;

[0058] S5: Output an oxygen concentration control quantity based on the relationship between the oxygen concentration deviation signal and the preset oxygen concentration deviation threshold, in order to correct the oxygen concentration of the target mixed gas, wherein:

[0059]

[0060] In the formula: u1(k) is the oxygen concentration control value, k represents the feedback value of the kth acquisition; K p K is the proportionality coefficient. i K is the second integral coefficient. d is the differential coefficient; b is the preset oxygen concentration deviation threshold and b>0. The proportional coefficient, the second integral coefficient, the differential coefficient, and the oxygen concentration deviation threshold can be selected with appropriate values ​​based on the characteristics of the respiratory system; this selection process is an empirical method known to those skilled in the art.

[0061] like Figure 3 As shown, the mixed oxygen control method provided by the present invention improves the real-time performance and accuracy of mixed oxygen control by superimposing oxygen concentration feedback control on oxygen flow feedback control to form a dual closed-loop control.

[0062] Another embodiment of the present invention provides a mixed-oxygen breathing device, which is based on the above-described mixed-oxygen control method. For example... Figure 1 As shown, in a preferred embodiment of the present invention, the oxygen mixing control device specifically includes: a mixing chamber having an air inlet, an oxygen inlet, and a mixed gas outlet;

[0063] An air passage, one end of which supplies air in, and the other end is connected to the air inlet of the mixing chamber;

[0064] An oxygen gas path, one end of which supplies oxygen, and the other end which connects to the oxygen inlet of the mixing chamber; and

[0065] An output gas path is provided, with one end connected to the mixed gas outlet of the mixing chamber and the other end connected to the ventilator to output the air and oxygen mixture.

[0066] The air path includes: a fan for adjusting the flow rate of the air path; and an air flow sensor for monitoring the flow rate of the air path; the oxygen path includes: a proportional valve for adjusting the flow rate of the oxygen path; the output path includes: a mixed flow sensor for monitoring the flow rate of the mixed gas; and an oxygen concentration sensor for monitoring the oxygen concentration of the mixed gas.

[0067] The oxygen mixing control device also includes a control unit connected to the air flow sensor, the mixing flow sensor, the oxygen concentration sensor, and the proportional valve, and capable of adjusting the opening of the proportional valve based on the monitoring results of the air flow sensor, the mixing flow sensor, and the oxygen concentration sensor.

[0068] Specifically, such as Figure 2 As shown, the control device includes an input module, a first control module, and a second control module, wherein:

[0069] The input module is used to set the target oxygen concentration in the mixed gas.

[0070] The first control module includes a selection switch, a start-stop control unit, and an integral control unit, wherein: the selection switch can selectively connect either the start-stop control unit or the integral control unit to the proportional valve; the start-stop control unit or the integral control unit is used to output an oxygen flow control quantity based on the monitoring results of the air flow sensor and the mixed flow sensor and the target mixed gas oxygen concentration, so as to adjust the opening of the proportional valve; wherein the expression for the oxygen flow control quantity is:

[0071]

[0072] In the formula: u(k) is the oxygen flow control quantity, and k represents the feedback value collected in the kth time; u min This is the preset minimum output value; u max K is the preset maximum output. I is the first integral coefficient, a is the preset oxygen flow deviation threshold and a>0; e(k) is the oxygen flow deviation signal, which is the difference between the target oxygen flow and the real-time oxygen flow, and the target oxygen flow is calculated from the oxygen concentration of the target mixed gas.

[0073] The second control module includes a PID control unit, which outputs an oxygen concentration control quantity based on the difference between the monitoring result of the oxygen concentration sensor and the oxygen concentration of the target mixed gas, thereby correcting the oxygen concentration of the target mixed gas. The expression for the oxygen concentration control quantity is:

[0074]

[0075] In the formula: u1(k) is the oxygen concentration control value, k represents the feedback value of the kth acquisition; K p K is the proportionality coefficient. i K is the second integral coefficient. d is the differential coefficient; b is the preset oxygen concentration deviation threshold and b>0; e1(k) is the oxygen concentration deviation signal, which is the difference between the target mixed gas oxygen concentration and the actual value of the mixed gas oxygen concentration.

[0076] Specifically, such as Figure 2 As shown, the selector switch can selectively connect the start-stop control unit or the integral control unit to the proportional valve based on the monitoring results of the air flow sensor and the mixed flow sensor, as well as the target oxygen flow rate. The difference between the monitoring results of the mixed flow sensor and the air flow sensor is the real-time oxygen flow rate, wherein:

[0077] When the absolute value of the difference between the real-time oxygen flow rate and the target oxygen flow rate does not exceed the preset oxygen flow rate deviation threshold, the selection switch connects the integral control unit and the proportional valve.

[0078] When the absolute value of the difference between the real-time oxygen flow rate and the target oxygen flow rate exceeds a preset oxygen flow rate deviation threshold, the selection switch connects the start-stop control unit and the proportional valve.

[0079] The following specific embodiment verifies the beneficial effects of the present invention. The mixed-gas control method provided by the present invention was verified on a breathing device. Three sets of parameters were set, with the target mixed gas oxygen concentration set to 30%, 60%, and 90%, respectively. The actual value of the mixed gas oxygen concentration (O2RT%) monitored by the breathing device and the O2Sebsor% detected by the device were recorded. Both the control accuracy and measurement accuracy were within the error range. In this embodiment, the coefficient of the PID control unit is set as: K p =0.012, K i =0.001, K d =0.00032; the coefficient of the integral control unit is set as: K I =0.24; the oxygen flow rate deviation threshold is set to a = 100; the u min =-50, the u max =50; the oxygen concentration deviation threshold is set to b=4. It is worth noting that this coefficient is only applicable to this system's operating condition; for other system conditions, it needs to be readjusted based on experience. Specific data are shown in the table below:

[0080] <![CDATA[Set value O2%]]> <![CDATA[Respiratory device monitoring value O2RT%]]> <![CDATA[Monitoring value of detection equipment, O2Sensor%]]> 30 30 29 60 60 61 90 90 90

[0081] The results above demonstrate that the control method of this patent exhibits high precision and rapid adjustment. After adjusting the oxygen concentration from 30% to 60% for three respiratory cycles, the monitored oxygen concentration (O2Sensor%) reached 61%. In contrast, traditional oxygen concentration control methods, relying on closed-loop control, require approximately 2 minutes, while flow rate regulation introduces accuracy deviations. The method of this invention, through a dual-closed-loop control approach, accurately achieves the control target within three respiratory cycles.

[0082] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0083] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0084] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0085] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for controlling oxygen mixing in a non-invasive breathing device, characterized in that, Includes the following steps: S1: Set the target oxygen concentration for the mixed gas, and calculate the target oxygen flow rate based on the target oxygen concentration for the mixed gas: In the formula: Target oxygen flow rate; Flow mix The flow rate of the mixed gas is the real-time flow rate; O2% is the target oxygen concentration in the mixed gas; Flow Air Real-time airflow; S2: Collect real-time oxygen flow rate and obtain the oxygen flow rate deviation signal between the real-time oxygen flow rate and the target oxygen flow rate: In the formula: e(k) is the oxygen flow rate deviation signal, and k represents the feedback value of the kth acquisition; The real-time oxygen flow rate is: S3: Output an oxygen flow control quantity based on the relationship between the oxygen flow deviation signal and the preset oxygen flow deviation threshold, so as to adjust the real-time oxygen flow, wherein: In the formula: u(k) is the oxygen flow control quantity, and k represents the feedback value collected in the kth time; u min u is the preset minimum output value. max K is the preset maximum output. I is the first integral coefficient, and a is the preset oxygen flow deviation threshold and a > 0; S4: Based on the execution of S1-S3, collect the actual value of the oxygen concentration of the mixed gas, and obtain the oxygen concentration deviation signal between the actual value of the oxygen concentration of the mixed gas and the target oxygen concentration of the mixed gas: e1(k) = O2% - O2RT% In the formula: e1(k) is the oxygen concentration deviation signal, k represents the feedback value of the kth acquisition; O2RT% is the actual value of the oxygen concentration of the mixed gas; S5: Output an oxygen concentration control quantity based on the relationship between the oxygen concentration deviation signal and the preset oxygen concentration deviation threshold, in order to correct the oxygen concentration of the target mixed gas, wherein: In the formula: u1(k) is the oxygen concentration control value, k represents the feedback value of the kth acquisition; K p K is the proportionality coefficient. i K is the second integral coefficient. d is the differential coefficient; b is the preset oxygen concentration deviation threshold and b > 0.

2. An oxygen mixing control device for a non-invasive breathing device, the oxygen mixing control device being based on the oxygen mixing control method of claim 1, the oxygen mixing control device comprising: A mixing chamber having an air inlet, an oxygen inlet, and a mixed gas outlet; An air passage, one end of which supplies air in, and the other end is connected to the air inlet of the mixing chamber; An oxygen gas path, one end of which supplies oxygen, and the other end of which is connected to the oxygen inlet of the mixing chamber; and An output gas path is provided, with one end connected to the mixed gas outlet of the mixing chamber and the other end connected to the ventilator to output the air and oxygen mixture. The air path includes: a fan for adjusting the flow rate of the air path; and an air flow sensor for monitoring the flow rate of the air path; the oxygen path includes: a proportional valve for adjusting the flow rate of the oxygen path; the output path includes: a mixed flow sensor for monitoring the flow rate of the mixed gas; and an oxygen concentration sensor for monitoring the oxygen concentration of the mixed gas. The feature is that the oxygen mixing control device further includes a control device, which is connected to the air flow sensor, the mixing flow sensor, the oxygen concentration sensor and the proportional valve, and can adjust the opening degree of the proportional valve according to the monitoring results of the air flow sensor, the mixing flow sensor and the oxygen concentration sensor.

3. The oxygen mixing control device for non-invasive breathing equipment according to claim 2, characterized in that, The control device includes an input module, a first control module, and a second control module, wherein: The input module is used to set the target oxygen concentration in the mixed gas. The first control module includes a selection switch, a start-stop control unit, and an integral control unit, wherein: the selection switch can selectively connect the start-stop control unit or the integral control unit to the proportional valve, and the start-stop control unit or the integral control unit is used to output an oxygen flow control quantity based on the monitoring results of the air flow sensor and the mixed flow sensor and the oxygen concentration of the target mixed gas, so as to adjust the opening of the proportional valve; The second control module includes a PID control unit, which is used to output an oxygen concentration control quantity based on the difference between the monitoring result of the oxygen concentration sensor and the oxygen concentration of the target mixed gas, so as to correct the oxygen concentration of the target mixed gas.

4. The oxygen mixing control device for non-invasive breathing equipment according to claim 3, characterized in that, The selector switch can selectively connect the start-stop control unit or the integral control unit to the proportional valve based on the monitoring results of the air flow sensor and the mixed flow sensor, as well as the target oxygen flow rate. The difference between the monitoring results of the mixed flow sensor and the air flow sensor is the real-time oxygen flow rate, wherein: When the absolute value of the difference between the real-time oxygen flow rate and the target oxygen flow rate does not exceed the preset oxygen flow rate deviation threshold, the selection switch connects the integral control unit and the proportional valve. When the absolute value of the difference between the real-time oxygen flow rate and the target oxygen flow rate exceeds a preset oxygen flow rate deviation threshold, the selection switch connects the start-stop control unit and the proportional valve.

5. The oxygen mixing control device for non-invasive breathing equipment according to claim 3, characterized in that, The expression for the oxygen flow control quantity is: In the formula: u(k) is the oxygen flow control quantity, and k represents the feedback value collected in the kth time; u min This is the preset minimum output value; u max K is the preset maximum output. I is the first integral coefficient, a is the preset oxygen flow deviation threshold and a > 0; e(k) is the oxygen flow deviation signal, which is the difference between the target oxygen flow and the real-time oxygen flow, and the target oxygen flow is calculated from the oxygen concentration of the target mixed gas.

6. The oxygen mixing control device for non-invasive breathing equipment according to claim 3, characterized in that, The expression for the oxygen concentration control quantity is: In the formula: u1(k) is the oxygen concentration control value, k represents the feedback value of the kth acquisition; K p K is the proportionality coefficient. i K is the second integral coefficient. d is the differential coefficient; b is the preset oxygen concentration deviation threshold and b > 0; e1(k) is the oxygen concentration deviation signal, which is the difference between the target mixed gas oxygen concentration and the actual value of the mixed gas oxygen concentration.

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