Flow control method, system and apparatus for gas conveying system, and storage medium

Abstract

The present invention relates to a flow control method, system and apparatus for a gas conveying system, and a storage medium. The method comprises: acquiring an actual pressure value at a gas outlet of a gas conveying system in real time; on the basis of the actual pressure value and a preset pressure value, adjusting in real time a preset upper limit flow of a gas conveyed by the gas conveying system, so as to obtain a target upper limit flow; acquiring an actual flow value at the gas outlet of the gas conveying system in real time; and by means of using a PID control method and on the basis of the target upper limit flow and the actual flow value, controlling a switch proportional valve of the gas conveying system in real time, so as to complete flow control of the gas conveying system. The present invention can achieve dynamic flow control, and involves a rapid and precise dynamic control process and high robustness, thus truly ensuring the safety of surgical operating spaces of medical apparatuses.

Description

Flow control method, system, device and storage medium for gas delivery system Technical Field

[0001] The present invention relates to the field of medical equipment, and in particular to a flow control method, system, device and storage medium for a gas delivery system. Background Art

[0002] Gas delivery systems are used to deliver gases (such as carbon dioxide) to the human body (such as the abdominal cavity, intestinal tract, and uterine cavity) during surgery, thereby creating a surgical space. Therefore, when using medical equipment such as laparoscopes and hysteroscopes, a gas delivery system is required.

[0003] In order to provide a good field of view and sufficient surgical operating space, and to ensure the safety of the gas delivered by the gas delivery system after entering the human body, the flow rate of the delivered gas needs to be controlled in real time to avoid insufficient field of view and surgical operating space when the flow rate is too small, and to avoid harm to the human body when the flow rate is too large.

[0004] However, in the current flow control technology of the gas delivery system of medical equipment, flow control is usually based on flow fluctuations. Flow fluctuations are closely related to pressure fluctuations. Therefore, this flow control method based on flow fluctuations cannot achieve truly smooth and stable regulation, which is not conducive to the operating environment of medical equipment. Technical issues

[0005] The technical problem to be solved by the present invention is how to more smoothly and stably adjust the flow rate of the gas delivery system of medical equipment to provide a safer surgical operation space. Technical Solutions

[0006] To solve the above technical problems, the present invention provides a flow control method for a gas delivery system, wherein the gas delivery system is provided with a switch proportional valve, and the method comprises:

[0007] Obtaining in real time the actual pressure value at the gas outlet of the gas delivery system;

[0008] According to the actual pressure value and the preset pressure value, the preset upper limit flow rate of the gas delivered by the gas delivery system is adjusted in real time to obtain a target upper limit flow rate;

[0009] Obtaining the actual flow value at the gas outlet of the gas delivery system in real time;

[0010] The PID control method is used to control the on-off proportional valve of the gas delivery system in real time according to the target upper limit flow rate and the actual flow rate value, thereby completing the flow control of the gas delivery system.

[0011] Optionally, adjusting a preset upper limit flow rate of gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate includes:

[0012] Obtaining a difference between the actual pressure value and the preset pressure value;

[0013] When the actual pressure value is less than the preset pressure value and the absolute value of the difference is greater than a first preset threshold, determining the preset upper limit flow rate as the target upper limit flow rate;

[0014] When the actual pressure value is less than the preset pressure value and the absolute value of the difference is less than or equal to the first preset threshold, obtaining a flow regulation function with the absolute value of the difference as an input variable, and calculating the target upper limit flow rate according to the flow regulation function;

[0015] When the actual pressure value is greater than or equal to the preset pressure value, the target upper limit flow rate is determined to be zero;

[0016] Wherein, the first preset threshold is greater than 0.

[0017] Optionally, the flow regulation function is formulated as follows:

[0018] Wherein, L2 is the target upper limit flow rate, f(·) is the flow rate adjustment function, L1 is the preset upper limit flow rate, P2 and P1 are the actual pressure value and the preset pressure value respectively, and C is the preset coefficient.

[0019] Optionally, when, within a preset time after the target upper limit flow rate is determined to be zero, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than or equal to a fourth preset threshold and less than or equal to a second preset threshold;

[0020] The step of adjusting the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate further includes:

[0021] Recalculate the target upper limit flow rate according to the flow adjustment function;

[0022] Wherein, the second preset threshold is less than or equal to the first preset threshold, and the fourth preset threshold is less than the second preset threshold;

[0023] and / or when, within a preset time after the target upper limit flow rate is determined to be zero, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than the second preset threshold;

[0024] The step of adjusting the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate further includes:

[0025] The preset upper limit flow rate is determined as the target upper limit flow rate.

[0026] Optionally, the PID control method is used to control the on / off proportional valve of the gas delivery system in real time according to the target upper limit flow rate and the actual flow rate value to complete the flow control of the gas delivery system, including:

[0027] Calculating a flow error based on the target upper limit flow and the actual flow value;

[0028] The flow error is used as the input variable of the position PID controller, and the opening of the switch proportional valve is used as the output variable of the position PID controller. The position PID controller is used to control the opening of the switch proportional valve in real time to complete the flow control of the gas delivery system.

[0029] Optionally, a flow sensor is provided at the gas outlet of the gas delivery system. Before acquiring the actual flow value at the gas outlet of the gas delivery system in real time, the method further includes:

[0030] The flow sensor is calibrated.

[0031] Optionally, calibrating the flow sensor includes:

[0032] Obtaining a maximum allowable flow rate of gas delivered by the gas delivery system, and obtaining a plurality of continuous allowable flow rate ranges of the gas delivery system based on the maximum allowable flow rate;

[0033] Within each of the allowable flow rates, using the gas delivery system to deliver gas to the gas outlet at a plurality of fitted flow rates, and using the flow sensor to obtain a flow acquisition signal at each of the fitted flow rates;

[0034] In each of the allowable flow ranges, curve fitting is performed based on all the fitting flow rates and the flow acquisition signals under all the fitting flow rates to obtain flow conversion equations of the flow sensor in each of the allowable flow ranges, thereby completing the calibration of the flow sensor.

[0035] In addition, the present invention also proposes a flow control system for a gas delivery system, wherein the gas delivery system is provided with an on-off proportional valve and is applied to the flow control method of the aforementioned gas delivery system, the system comprising:

[0036] A real-time pressure acquisition module, used to obtain the actual pressure value at the gas outlet of the gas delivery system in real time;

[0037] An upper limit flow rate adjustment module is used to adjust the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate;

[0038] A real-time flow acquisition module, used to acquire the actual flow value at the gas outlet of the gas delivery system in real time;

[0039] The flow feedback control module is used to use the PID control method to perform real-time control on the on-off proportional valve of the gas delivery system according to the target upper limit flow and the actual flow value, thereby completing the flow control of the gas delivery system.

[0040] In addition, the present invention also proposes a flow control device for a gas delivery system, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the method steps in the aforementioned flow control method for the gas delivery system when executed.

[0041] In addition, the present invention also provides a computer storage medium, which includes: at least one instruction, and when the instruction is executed, the method steps in the flow control method of the gas delivery system are implemented. Beneficial effects

[0042] In the flow control method, system, device and storage medium of the gas delivery system provided by the present invention, the preset upper limit flow rate refers to the upper limit value of the target flow rate of the gas delivered by the gas delivery system, which is set in advance. After the preset upper limit flow rate is set, the gas delivery system will deliver gas within the range limited by the preset upper limit flow rate; because when the medical equipment starts to deliver gas through the gas delivery system, the actual flow rate in the gas circuit will increase, and the actual pressure in the hand operation space will also increase accordingly. When the actual pressure reaches the expected pressure value and stabilizes, the actual flow rate in the gas circuit may not reach the target flow rate, that is, the actual flow rate in the gas circuit is not necessarily delivered according to the preset upper limit flow rate; therefore, the preset pressure value and the real-time pressure at the gas outlet of the gas delivery system are combined to determine the actual flow rate of the gas delivery system. The preset upper limit flow rate is adjusted based on the actual pressure value. Based on the target upper limit flow rate obtained after adjustment, it can not only realize the flow control in the real gas path environment, but also fully consider the mutual influence between the pressure and flow in the gas path, and realize the regulation function of the pressure in the gas path, so that the flow control of the gas delivery system of the medical equipment is smoother and more stable. After obtaining the target upper limit flow rate value, it is also combined with the actual flow value obtained in real time, and the PID control method is used to control the switch proportional valve in real time. It can quickly respond to the deviation between the target upper limit flow rate value and the actual flow value and correct it, so as to realize dynamic control of the flow rate. The dynamic control process is fast, accurate and robust, which can truly ensure the safety of the surgical operation space of the medical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] FIG1 shows a structural diagram of a gas delivery system in a first embodiment of the present invention;

[0045] FIG2 shows a flow chart of a method for controlling flow of a gas delivery system according to a first embodiment of the present invention;

[0046] FIG3 shows a complete flow chart of adjusting the preset upper limit flow rate in step S2 in the first embodiment of the present invention;

[0047] FIG4 shows a flow chart of controlling the on-off proportional valve according to the target upper limit flow rate and the actual flow rate value in the first embodiment of the present invention;

[0048] FIG5 shows a structural diagram of a flow control system of a gas delivery system in a second embodiment of the present invention. Modes for Carrying Out the Invention

[0049] The technical solutions of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments of the present invention and the features therein may be combined with each other unless there is a conflict.

[0050] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0051] Example 1

[0052] The gas delivery system consists of a gas source and a proportional on / off valve at the inlet, as well as a pressure sensor and flow sensor at the outlet. The inlet and outlet are connected by a gas pipeline. When the proportional on / off valve is open, gas is delivered from the inlet to the outlet through the gas pipeline. When the proportional on / off valve is closed, gas delivery stops. Controlling the opening of the proportional on / off valve controls the flow rate of the delivered gas. The pressure sensor detects the pressure signal (in digital format, without units) at the outlet, and the flow sensor detects the flow signal (in digital format, without units) at the outlet. In practice, the gas delivery system also utilizes a microcontroller (MCU, electrically connected to both the pressure and flow sensors) to convert the pressure signal from the pressure sensor to the actual pressure value, and the flow signal from the flow sensor to the actual flow value.

[0053] As shown in FIG2 , this embodiment provides a flow control method for a gas delivery system, the method comprising:

[0054] S1: obtaining the actual pressure value at the gas outlet of the gas delivery system in real time;

[0055] S2: adjusting a preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate;

[0056] S3: obtaining the actual flow value at the gas outlet of the gas delivery system in real time;

[0057] S4: Using a PID control method, the on-off proportional valve of the gas delivery system is controlled in real time according to the target upper limit flow rate and the actual flow rate value to complete the flow control of the gas delivery system.

[0058] In the flow control method of the present embodiment, the preset upper limit flow rate refers to the upper limit value of the target flow rate of the gas delivered by the gas delivery system, which is set in advance. After the preset upper limit flow rate is set, the gas delivery system will deliver gas within the range limited by the preset upper limit flow rate; because when the medical equipment starts to deliver gas through the gas delivery system, the actual flow rate in the gas circuit will increase, and the actual pressure in the hand operation space will also increase accordingly. When the actual pressure reaches the expected pressure value and stabilizes, the actual flow rate in the gas circuit may not reach the target flow rate, that is, the actual flow rate in the gas circuit is not necessarily delivered according to the preset upper limit flow rate; therefore, the preset upper limit flow rate is determined by the preset pressure value and the actual pressure value at the gas outlet of the gas delivery system obtained in real time. Adjustments are made, and based on the target upper limit flow obtained after the adjustment, it can not only realize the flow control in the real gas path environment, but also fully consider the mutual influence between the pressure and flow in the gas path, and realize the regulation function of the pressure in the gas path, thereby making the flow control of the gas delivery system of the medical equipment smoother and more stable, with smaller fluctuations; after obtaining the target upper limit flow value, it is also combined with the actual flow value obtained in real time, and the PID control method is used to control the switch proportional valve in real time, which can quickly respond to the deviation between the target upper limit flow value and the actual flow value and correct the deviation, thereby realizing dynamic feedback and dynamic control of the flow, and the dynamic control process is fast, accurate, and robust, thereby truly ensuring the safety of the surgical operation space of the medical equipment.

[0059] Each step of the flow control method of the gas delivery system of this embodiment is described in detail below.

[0060] In this embodiment, S1 includes: using a pressure sensor to obtain the actual pressure value at the gas outlet of the gas delivery system in real time.

[0061] Since the pressure sensor detects the pressure acquisition signal at the air outlet, which is a unitless digital signal, there is a certain conversion relationship between the pressure acquisition signal and the actual pressure value at the air outlet. Therefore, before S1, the conversion relationship between the pressure acquisition signal and the actual pressure value can be obtained. Then, in S1, the pressure sensor is used to obtain the pressure acquisition signal at the air outlet, and then the obtained pressure conversion relationship is used to convert the pressure acquisition signal to obtain the actual pressure value.

[0062] Furthermore, before S1, the pressure sensor can be calibrated so that the actual pressure value obtained from the pressure acquisition signal in S1 based on the conversion relationship is more accurate. The pressure sensor calibration method can adopt the existing calibration method, and the specific details are not repeated here.

[0063] Preferably, S1 includes:

[0064] When the switch proportional valve is in an open state, the switch proportional valve is intermittently closed at a preset frequency, and when the switch proportional valve is in a closed state, the actual pressure value at the gas outlet of the gas delivery system is collected by using the pressure sensor;

[0065] The off state of the switch proportional valve is maintained for a time in the order of seconds or milliseconds.

[0066] Since the gas is flowing when the gas delivery system is delivering gas, the pressure values ​​at various locations in the gas circuit are not the same, and thus the actual pressure value corresponding to the pressure acquisition signal detected by the pressure sensor at the gas outlet is not the same as the pressure value delivered to the surgical operation space. This embodiment intermittently shuts off the switch proportional valve. Since the gas in the gas circuit is in a stationary state when the switch proportional valve is in the off state, the actual pressure value corresponding to the pressure acquisition signal of the pressure sensor when the switch proportional valve is in the off state can be read to avoid the influence of the unequal pressure caused by the flowing gas, effectively improve the accuracy of the actual pressure value, and thus ensure the accuracy of subsequent flow control. The off state of the switch proportional valve is maintained for a time of seconds or milliseconds, which can make the off state of the switch proportional valve extremely short, avoid the influence of its off process on the delivered gas, and ensure the reliability of the entire flow control process while ensuring the accuracy of the actual pressure value.

[0067] Preferably, S2 includes:

[0068] S21: Obtaining the difference between the actual pressure value and the preset pressure value;

[0069] S22A: When the actual pressure value is less than the preset pressure value and the absolute value of the difference is greater than a first preset threshold, determining the preset upper limit flow rate as the target upper limit flow rate;

[0070] S22B: When the actual pressure value is less than the preset pressure value and the absolute value of the difference is less than or equal to the first preset threshold, obtaining a flow regulation function with the absolute value of the difference as an input variable, and calculating the target upper limit flow rate according to the flow regulation function;

[0071] S22C: When the actual pressure value is greater than or equal to the preset pressure value, setting the target upper limit flow rate to zero;

[0072] Wherein, the first preset threshold is greater than 0.

[0073] In the above-mentioned flow adjustment process, the preset upper limit flow is the upper limit value of the flow of the conveying gas set by the user at the beginning, which can be displayed and viewed on the user interface; the preset pressure value is also the pressure value in the gas circuit set by the user at the beginning, which can also be displayed and viewed on the user interface; the first preset threshold is a pre-set pressure threshold; the preset upper limit flow is adjusted through the above steps, and the target upper limit flow obtained is the upper limit value of the flow of the gas actually conveyed by the gas delivery system. This value cannot be displayed and viewed through the user interface, and is only dynamically adjusted within the entire system.

[0074] This embodiment uses the above-mentioned flow adjustment method to, on the one hand, achieve flow regulation based on pressure fluctuations, which is more in line with the actual gas path environment of the medical equipment gas delivery system and realizes flow control in the actual gas path environment; on the other hand, it fully considers the mutual influence between pressure and flow in the gas path, and can also achieve a certain degree of regulation function on the pressure in the gas path, thereby making the flow control of the gas delivery system of the medical equipment smoother and more stable, with smaller fluctuations, which is conducive to providing a safer surgical operation space.

[0075] Among them, in the above-mentioned flow adjustment process, by comparing the actual pressure value with the preset pressure value, it can be determined whether the gas delivery system needs to continue to deliver gas, that is, whether the target upper limit flow is set to zero, and then the switch control state of the switch proportional valve can be determined, and the flow control is achieved through the switch control state of the switch proportional valve; when the actual pressure value is less than the preset pressure value, it means that the gas delivered by the gas delivery system does not meet the requirements, and the target upper limit flow needs to be set to a state greater than zero, that is, it is necessary to control and maintain the open state of the switch proportional valve to ensure continued gas delivery; and when the actual pressure value is greater than or equal to the preset pressure value, it means that the gas delivered by the gas delivery system meets the requirements, and the target upper limit flow needs to be set to zero, that is, the control changes the open state of the switch proportional valve (that is, close the switch proportional valve) to stop gas delivery.

[0076] When the on-off proportional valve remains in the open state, that is, when the actual pressure value is less than the preset pressure value, the absolute value of the difference is further compared with the first preset threshold. When the absolute value of the difference is greater than the first preset threshold, it indicates that the actual pressure value differs significantly from the preset pressure value and is still far from the desired pressure value. In this case, the preset upper limit flow rate is set as the target upper limit flow rate, and gas can be delivered at a higher flow rate, that is, the gas pressure and flow rate can be achieved at a faster rate. When the absolute value of the difference is less than or equal to the first preset threshold, it indicates that the actual pressure value differs slightly from the preset pressure value and is closer to the desired pressure value. In this case, the target upper limit flow rate is calculated according to the flow adjustment function, and gas can be delivered at a lower flow rate. Because the flow adjustment function uses the absolute value of the difference as an input variable, it can achieve a smoother adjustment of the actual pressure and flow rate to the required level. It can also achieve real-time flow adjustment, reducing the fluctuation of flow control in the gas circuit, making the entire gas delivery process safer and truly ensuring the safety of the surgical operating space.

[0077] It should be understood that since the entire flow control process is a real-time control process and there is air leakage in the air circuit (such as opening the air release valve, etc.), further, when the actual pressure value is greater than or equal to the preset pressure value and the absolute value of the difference between the actual pressure value and the preset pressure value is less than the third preset threshold value, the target upper limit flow rate is not immediately set to zero, but the target upper limit flow rate is maintained at the original calculation method, that is, the target upper limit flow rate is calculated according to the flow adjustment function, and air is delivered at a smaller and slower flow rate, which can avoid the phenomenon that the actual pressure value does not reach the preset pressure value due to air leakage in the medical equipment; and when the actual pressure value is greater than the preset pressure value and the absolute value of the difference between the actual pressure value and the preset pressure value is greater than or equal to the third preset threshold value, it is determined that the actual pressure value is truly greater than the preset pressure value, and the target upper limit flow rate is set to zero to achieve the control of stopping air delivery.

[0078] The third preset threshold value can be equal to the first preset threshold value, or can be greater than or equal to the first preset threshold value, depending on the specific circumstances. For example, when the value of the first preset threshold value is 2, the value of the third preset threshold value can be 1, that is, when the actual pressure value exceeds the preset pressure value by 1 mmHg or more, the target upper limit flow rate is determined to be zero; for another example, when the value of the first preset threshold value is 2, the value of the third preset threshold value can be 3, that is, when the actual pressure value exceeds the preset pressure value by 3 mmHg or more, the target upper limit flow rate is determined to be zero; for another example, when the value of the first preset threshold value is 2, the value of the third preset threshold value can be 2, that is, when the actual pressure value exceeds the preset pressure value by 2 mmHg or more, the target upper limit flow rate is determined to be zero.

[0079] Preferably, the flow regulation function is formulated as follows:

[0080] Wherein, L2 is the target upper limit flow rate, f(·) is the flow rate adjustment function, L1 is the preset upper limit flow rate, P2 and P1 are the actual pressure value and the preset pressure value respectively, and C is the preset coefficient.

[0081] By using the flow control function with the absolute value of the difference between the actual pressure value and the preset pressure value as the input variable, real-time adjustment of the flow rate is achieved, reducing the volatility of the flow rate in the gas path, and making the entire gas delivery process safer.

[0082] In actual design, the first preset threshold can be set and adjusted according to actual conditions. For example, the first preset threshold is set to 2 mmHg, and the actual pressure value is P2 and the preset pressure value is P1; then:

[0083] (1) When P2 < P1 (P2-P1 is a negative value) and |P2-P1| > 2 mmHg, the preset upper limit flow rate is determined as the target upper limit flow rate;

[0084] (2) When P2 < P1 (P2-P1 is still a negative value) and 0 < |P2-P1| ≤ 2 mmHg, the target upper limit flow rate is calculated according to the flow adjustment function f(|P2-P1|);

[0085] (3) When P2=P1 (P2-P1 is 0), or when P2>P1 (P2-P1 is a positive value), the target upper limit flow rate is set to 0 (equivalent to closing the switch proportional valve).

[0086] Other settings of the first preset threshold and the corresponding process of determining the target upper limit flow rate are similar to the above case and are not listed here.

[0087] In an optional embodiment, the preset coefficient C in the flow regulation function is a positive value, such as 2, 3, 4, etc., or 2.5, 3.6, 4.8, etc.

[0088] In another optional embodiment, the preset coefficient C in the flow regulation function is a function value, such as C=(P2-P1) 2 +b.

[0089] The above preset coefficients C are selected according to specific circumstances and are not limited here.

[0090] Preferably, when, within a preset time after the target upper limit flow rate is determined to be zero, the actual pressure value is less than the preset pressure value and the absolute value of the difference is greater than or equal to a fourth preset threshold and less than or equal to the second preset threshold;

[0091] S2 also includes:

[0092] Recalculate the target upper limit flow rate according to the flow adjustment function;

[0093] The second preset threshold is smaller than or equal to the first preset threshold, and the fourth preset threshold is smaller than the second preset threshold.

[0094] Preferably, when, within a preset time after the target upper limit flow rate is determined to be zero, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than the second preset threshold;

[0095] S2 also includes:

[0096] The preset upper limit flow rate is determined as the target upper limit flow rate.

[0097] In the actual use of medical equipment, such as a pneumoperitoneum machine, the pneumoperitoneum needle in the pneumoperitoneum machine is inserted into the patient's belly through a minimally invasive surgical incision. When the pneumoperitoneum machine stops delivering gas, so that the target upper limit flow rate in the gas circuit and the flow rate of gas delivered by the gas output system are both 0, the medical equipment is equipped with a valve, and there will be air leakage during the opening and closing process of the valve. For example, the air release valve in the internal air circuit of the pneumoperitoneum machine is activated to exhaust the gas in the surgical operation space; if the air release valve is not opened to exhaust, there will also be air leakage at the minimally invasive incision. These situations are all normal leaks, and the leakage flow rate is relatively small (or the leakage speed is relatively slow). When medical staff remove medical equipment such as the pneumoperitoneum needle, or add a new surgical incision, or press the patient's belly, the pressure in the surgical cavity will suddenly decrease, that is, the leakage flow rate is relatively large (or the leakage speed is relatively fast).

[0098] Therefore, there is a situation of gas leakage in the actual gas path environment of the medical device, and because the flow control process is a real-time control process, within the preset time after the target upper limit flow rate is determined to be zero, the actual pressure value will not maintain a fixed value due to the gas leakage, but will slowly approach the preset pressure value and slowly fall below the preset pressure value. If, within the preset time after the target upper limit flow rate is determined to be zero, the gas leakage reaches the standard requiring gas replenishment, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than or equal to the fourth preset threshold, and the target upper limit flow rate needs to be reset to replenish gas; if, when gas replenishment is required, the gas leakage is slow and the difference from the actual required pressure value is small, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is less than or equal to the second preset threshold (the threshold is less than or equal to the first preset threshold); at this time, the actual pressure value is not much different from the expected pressure value, and a new target upper limit flow rate is obtained again through the flow adjustment function, and gas is replenished at a smaller and slower flow rate to achieve new flow control, so that the actual pressure and flow in the gas path are stable at the expected values, providing a smooth and safe surgical operation space. However, within the preset time after the target upper limit flow rate is determined to be zero, if the air leakage is fast and differs greatly from the actual required pressure value when air supplementation is needed, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than the second preset threshold value; at this time, the actual pressure value is significantly different from the expected pressure value, so the target upper limit flow rate is determined based on the preset upper limit flow rate, and air is supplemented at a larger and faster flow rate to achieve new flow control, so that the actual pressure and flow in the air circuit are stable at the expected value, providing a smooth and safe surgical operation space.

[0099] Similar to the first preset threshold, the second preset threshold and the fourth preset threshold are also preset pressure thresholds, which are pre-set and adjusted according to actual conditions. For example, if the preset time t is 5s, the second preset threshold is 1mmHg, and the fourth preset threshold is 0.5mmHg, then:

[0100] (4) When the target upper limit flow rate is set to 0 5 s later, P2 gradually decreases due to leakage, resulting in P2 < P1 (P2-P1 is a negative value at this time) and 0.5 mmHg ≤ |P2-P1| ≤ 1 mmHg, the target upper limit flow rate is calculated according to the flow adjustment function f(|P2-P1|);

[0101] (5) When 5 seconds after the target upper limit flow rate is set to 0, P2 gradually decreases due to leakage, resulting in P2 < P1 (P2-P1 is a negative value at this time) and |P2-P1| > 1 mmHg, the preset upper limit flow rate is determined as the target upper limit flow rate.

[0102] In this embodiment, the flow regulation function f(|P2-P1|) has the same structure as the flow regulation function in the aforementioned S22B, and the preset coefficient C therein may be the same as or different from the preset coefficient in the flow regulation function in the aforementioned S22B.

[0103] It should be understood that during the actual flow control process, within the preset time after the target upper limit flow is set to 0, when the actual pressure value is less than the preset pressure value but the absolute value of the difference is less than the fourth preset threshold, the fourth preset threshold is less than the second preset threshold. For example, when the fourth preset threshold is 0.5 mmHg and the second preset threshold is 1 mmHg, then when P2 < P1 and |P2-P1| < 0.5 mmHg, the target upper limit flow is not immediately calculated according to the flow adjustment function f(|P2-P1|); that is, at this time, it is considered that the leakage in the gas circuit has not affected the actual pressure and flow, and the actual pressure and flow in the gas circuit are still balanced at the expected value. The target upper limit flow is still maintained at 0, and the target upper limit flow is not reset. When the actual pressure value is less than the preset pressure value and the absolute value of the difference is greater than the fourth preset threshold, that is, when P2 < P1 and |P2-P1| ≥ 0.5 mmHg, the target upper limit flow is reset according to the method described in (4) (5) above.

[0104] The following example illustrates the entire process of adjusting the preset upper limit flow rate to obtain the target upper limit flow rate:

[0105] Before starting the gas delivery system, the preset pressure value P1 = 35 mmHg, the preset upper limit flow rate L1 = 20 L / min, the first preset threshold value is 2 mmHg, the fourth preset threshold value is 0.5 mmHg, and the second preset threshold value is 1 mmHg;

[0106] When the gas delivery system starts to supply gas, the gas circuit supplies gas to the surgical operation space (such as the abdominal cavity) at a preset upper limit flow rate L1 = 20L / min; when the actual pressure value P2 in the surgical operation space reaches 33mmHg, the gas circuit supplies gas to the surgical operation space at a target upper limit flow rate L2 = 10L / min [the preset coefficient C is 4, calculated by the flow adjustment function L2 = f(|P2-P1|) = (35-33)*20 / 4L / min = 10L / min]. When the actual pressure value P2 in the surgical operation space reaches 34mmHg, the gas circuit supplies gas to the surgical operation space at the refreshed target upper limit flow rate L2 = 5L / min [the flow regulation function L2 = f(|P2-P1|) = (35-34)*20 / 4L / min = 5L / min] is used to supply air into the surgical operation space (here we only take the two integers 33mmHg and 34mmHg as examples. In fact, 33.1mmHg, 33.2mmHg, 33.3mmHg, 33.4mmHg, ... all correspond to different target upper limit flow rates. The actual pressure value is within the range of 33-35mmHg, and the calculated target upper limit flow rate is constantly being refreshed, and its value is getting smaller and smaller, that is, the air supply flow rate is getting smaller and smaller, and the air supply speed is getting slower and slower).

[0107] The actual pressure value P2 in the surgical operating space is generally unlikely to reach exactly 35 mmHg in an actual gas circuit environment. For example, if the actual pressure value P2 in the surgical operating space reaches 36 mmHg, the gas delivery system stops supplying gas, causing the target upper limit flow rate in the gas circuit and the flow rate of gas delivered by the gas delivery system to both be 0. The vent valve in the gas circuit within the gas delivery system is activated to exhaust the gas in the surgical operating space. The exhaust flow rate is small, and the actual pressure value in the surgical operating space after exhaust may be exactly 35 mmHg or may be lower than 35 mmHg, such as 34.5 mmHg. At this time, the absolute value of the difference between the actual pressure value P2 and the preset pressure value P1 is greater than or equal to the fourth preset threshold and less than the second preset threshold. Gas delivery is then restarted, and the target upper limit flow rate L2 of the gas circuit is now 2.5 L / min [given by the flow adjustment function L2 = f(|P2-P1|) = (35-34.5)*20 / 4 L / min]. This cycle is repeated until the gas pressure in the surgical operating space tends to balance, and the gas flow also tends to balance. If the target upper limit flow rate in the gas circuit and the flow rate of gas delivered by the gas output system are both 0, a large air leakage flow rate occurs, and the actual pressure value P2 in the surgical operation space decreases rapidly, for example, it decreases to 30 mmHg. At this time, the absolute value of the difference between the actual pressure value P2 and the preset pressure value P1 is greater than the second preset threshold value, and the gas supply is started again. The target upper limit flow rate L2 is 20 L / min (equal to the preset upper limit flow rate L2), that is, the pneumoperitoneum machine quickly replenishes air into the manual operation space at a maximum flow rate of 20 L / min. When the actual pressure value P2 in the surgical operation space reaches 33 mmHg, gas is supplied at 10 mmHg.

[0108] In the above example, when the gas pressure in the surgical operating space is low (i.e., there is less gas), the insufflator inflates at a high flow rate, allowing for rapid inflating. When the insufflator approaches the preset pressure value set by the user, it inflates at a low flow rate. This low flow rate is adjusted in real time based on a comparison between the actual pressure value and the preset pressure value. The closer the actual pressure value is to the preset pressure value, the lower the inflation flow rate. This flow control method of this embodiment can quickly achieve a balance between the pressure and flow rate in the surgical operating space, making the entire inflation process safer and truly providing a safer surgical operating space.

[0109] In this embodiment, it is assumed that the first preset threshold, the second preset threshold, the third preset threshold and the fourth preset threshold are m1, m2, m3 and m4 respectively. The complete process of the above S2 is shown in FIG3 .

[0110] This embodiment S3 includes:

[0111] The flow sensor is used to obtain the actual flow value at the gas outlet of the gas delivery system in real time.

[0112] Since the flow sensor detects the flow collection signal at the air outlet, which is a unitless digital signal, there is a certain conversion relationship between the flow collection signal and the actual flow value at the air outlet. Therefore, before S3, the conversion relationship between the flow collection signal and the actual flow value can be obtained. Then, in S3, the flow sensor is used to obtain the flow collection signal at the air outlet, and then the obtained flow conversion relationship is used to convert the flow collection signal to obtain the actual flow value.

[0113] Furthermore, before S3, the method further includes:

[0114] The flow sensor is calibrated.

[0115] In a gas path environment, it is usually closed. The greater the flow rate, the greater the gas pressure will be, causing gas compression, which in turn further affects the gas flow rate. In addition, the gas path is easily disturbed by factors such as external temperature. Therefore, the flow conversion relationship corresponding to the flow sensor is not a simple linear relationship, and it cannot even be fitted once by a nonlinear formula. In this embodiment, a more accurate flow conversion relationship can be obtained through the calibration of the flow sensor, and then an accurate actual flow value can be obtained, effectively improving the flow control accuracy.

[0116] Specifically, calibrating the flow sensor includes:

[0117] Obtaining a maximum allowable flow rate of gas delivered by the gas delivery system, and obtaining a plurality of continuous allowable flow rate ranges of the gas delivery system based on the maximum allowable flow rate;

[0118] Within each of the allowable flow rates, using the gas delivery system to deliver gas to the gas outlet at a plurality of fitted flow rates, and using the flow sensor to obtain a flow acquisition signal at each of the fitted flow rates;

[0119] In each of the allowable flow ranges, curve fitting is performed based on all the fitting flow rates and the flow acquisition signals under all the fitting flow rates to obtain flow conversion equations of the flow sensor in each of the allowable flow ranges, thereby completing the calibration of the flow sensor.

[0120] The flow conversion relationship within each allowable flow range is obtained through the above-mentioned segmented fitting, which can optimize the flow conversion relationship of the entire flow sensor, so that the conversion of the flow acquisition signal within each segmented interval (that is, each allowable flow range) is accurate, thereby improving the accuracy of the actual flow value.

[0121] Assuming that the upper limit of the flow rate of the gas transported by the gas delivery system (i.e., the maximum allowable flow rate) is 50L / min, the flow rate range of the gas transported is 0~50L / min. This range is sliced ​​into several segments and divided into multiple continuous allowable flow rate ranges: [0-5], [5-10], [10-15], ..., [45-50], all in L / min.

[0122] For each flow rate range, there is a corresponding conversion relationship between the actual flow value x and the flow acquisition signal y. In each flow rate range, gas is delivered to the outlet according to multiple fitting flow rates, and the flow sensor is used to obtain the flow acquisition signal at each fitting flow rate, obtaining multiple groups of (x, y). These (x, y) are used to perform curve fitting to form a segmented fitting curve for each flow rate range:

[0123] When x∈[0,5], y=g1(x);

[0124] When x∈[5,10], y=g2(x);

[0125] When x∈[10,15], y=g3(x);

[0126] …

[0127] When x∈[45,50], y=g n (x).

[0128] The above segmented fitting curve is the flow conversion equation under each flow allowable range.

[0129] It should be understood that when fitting the curve, all (x, y) values ​​within each flow rate range not only indicate the range of x (i.e., the actual flow rate value), but also indirectly indicate the range of y (i.e., the flow rate acquisition signal). During the acquisition of the actual flow rate value in S3, the flow rate acquisition signal y from the flow sensor is read and the corresponding flow rate conversion equation is determined based on this signal. Substituting this into the corresponding flow rate conversion equation yields the corresponding actual flow rate value x.

[0130] Preferably, as shown in FIG4 , S4 includes:

[0131] S41: Calculating a flow error according to the target upper limit flow rate and the actual flow rate value;

[0132] S42: Using the flow error as the input variable of the position PID controller and the opening of the switch proportional valve as the output variable of the position PID controller, the position PID controller is used to perform real-time control on the opening of the switch proportional valve to complete the flow control of the gas delivery system.

[0133] Taking the flow error between the target upper limit flow and the actual flow value as the input variable, the flow feedback adjustment can be realized. Based on the position PID control method, the opening of the switch proportional valve is controlled by the flow deviation to realize flow control with high control accuracy and good stability.

[0134] In S41, the flow error at the kth sampling moment is: e k =L 2k -l k ;

[0135] Among them, e k , L 2k and l k are the flow error, target upper limit flow and actual flow value at the kth sampling moment, respectively, and k is a positive integer.

[0136] In S42, the expression of the position PID controller is:

[0137] Among them, u k is the output value of the position PID controller at the kth sampling moment, that is, the opening of the switch proportional valve at the kth sampling moment; e k-1 is the input value of the position PID controller at the k-1th sampling moment, that is, the flow error at the k-1th sampling moment; e j is the input value of the position PID controller at the jth sampling moment, that is, the flow error at the jth sampling moment; K p , K i and K d They are the proportional adjustment coefficient, integral adjustment coefficient and differential adjustment coefficient of the position PID controller respectively.

[0138] Based on the above position PID controller, the real-time target upper limit flow and actual flow value are input into the position PID controller, and the opening of the switch proportional valve is output in real time to achieve real-time control of the flow.

[0139] Example 2

[0140] This embodiment provides a flow control system for a gas delivery system. The gas delivery system is provided with an on-off proportional valve and is applied to the flow control method for the gas delivery system of the first embodiment. As shown in FIG5 , the system includes:

[0141] A real-time pressure acquisition module, used to obtain the actual pressure value at the gas outlet of the gas delivery system in real time;

[0142] An upper limit flow rate adjustment module is used to adjust the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate;

[0143] A real-time flow acquisition module, used to acquire the actual flow value at the gas outlet of the gas delivery system in real time;

[0144] The flow feedback control module is used to use the PID control method to perform real-time control on the on-off proportional valve of the gas delivery system according to the target upper limit flow and the actual flow value, thereby completing the flow control of the gas delivery system.

[0145] The flow control system provided in this embodiment obtains the actual pressure value at the outlet of the gas delivery system through a real-time pressure acquisition module, and uses an upper limit flow adjustment module to adjust the preset upper limit flow in combination with a preset pressure value. Based on the target upper limit flow obtained after adjustment, it can not only realize flow control in a real gas path environment, but also fully consider the mutual influence between pressure and flow in the gas path, and realize the regulation function of the pressure in the gas path, so that the flow control of the gas delivery system of the medical equipment is smoother and more stable; after obtaining the target upper limit flow value, it is also combined with the actual flow value obtained in real time by the real-time flow acquisition module, and the PID control method is used to control the switch proportional valve in real time through the flow feedback control module, which can quickly respond to the deviation between the target upper limit flow value and the actual flow value and correct the deviation, thereby realizing dynamic control of the flow. The dynamic control process is fast, accurate, and robust, and can truly ensure the safety of the surgical operation space of the medical equipment.

[0146] The functions of each module of the flow control system of the gas delivery system described in this embodiment correspond to the steps of the flow control method of the gas delivery system in Example 1. Therefore, for the details not fully described in this embodiment, please refer to the specific description of Example 1 and Figures 1 to 4, and will not be repeated here.

[0147] Example 3

[0148] This embodiment also provides a flow control device for a gas delivery system, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed, the method steps in the flow control method for the gas delivery system of the first embodiment are implemented.

[0149] Through a computer program stored in the memory and running on the processor, the target upper limit flow rate is adjusted based on pressure fluctuations, and the PID control method is combined to achieve dynamic control of the flow rate. The dynamic control process is fast, accurate, and robust, which can truly ensure the safety of the surgical operation space of medical equipment.

[0150] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor. The processor is the control center of a computer device, connecting all parts of the entire computer device using various interfaces and lines.

[0151] The memory can be used to store computer programs and / or models. The processor implements various functions of the computer device by running or executing the computer programs and / or models stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system and at least one application required for a function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created based on the use of the mobile phone (such as audio data, video data, etc.). In addition, the memory can include high-speed random access memory and can also include non-volatile memory, such as a hard disk, internal memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0152] It should be understood that each process and / or box in the flowchart and / or block diagram, as well as a combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by a computer program. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0153] These computer programs may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0154] These computer programs can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0155] This embodiment further provides a computer storage medium, which includes: at least one instruction, which implements the method steps of the flow control method of the gas delivery system of embodiment 1 when the instruction is executed.

[0156] By executing a computer storage medium containing at least one instruction, the target upper limit flow rate is adjusted based on pressure fluctuations, and the PID control method is combined to achieve dynamic control of the flow rate. The dynamic control process is fast, accurate, and robust, thereby truly ensuring the safety of the surgical operation space of medical equipment.

[0157] Similarly, for details not yet provided in this embodiment, please refer to the specific descriptions of Embodiment 1, Embodiment 2 and Figures 1 to 5, and will not be repeated here.

[0158] Obviously, the embodiments described above are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, those skilled in the art may make other different forms of changes or modifications without making any creative work, and all of these should fall within the scope of protection of the present invention.

Claims

1. A flow control method for a gas delivery system, wherein the gas delivery system is provided with a switch proportional valve; characterized in that: The method comprises: Acquire the actual pressure value at the gas outlet of the gas delivery system in real time; According to the actual pressure value and the preset pressure value, the preset upper limit flow rate of the gas delivered by the gas delivery system is adjusted in real time to obtain a target upper limit flow rate; Acquire the actual flow value at the gas outlet of the gas delivery system in real time; The PID control method is used to control the switch proportional valve of the gas delivery system in real time according to the target upper limit flow rate and the actual flow rate value, thereby completing the flow control of the gas delivery system.

2. The method according to claim 1, characterized in that The step of adjusting the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate includes: Obtaining a difference between the actual pressure value and the preset pressure value; When the actual pressure value is less than the preset pressure value and the absolute value of the difference is greater than a first preset threshold, determining the preset upper limit flow rate as the target upper limit flow rate; When the actual pressure value is less than the preset pressure value and the absolute value of the difference is less than or equal to the first preset threshold, obtaining a flow regulation function with the absolute value of the difference as an input variable, and calculating the target upper limit flow according to the flow regulation function; When the actual pressure value is greater than or equal to the preset pressure value, the target upper limit flow rate is determined to be zero; Wherein, the first preset threshold is greater than 0.

3. The method according to claim 2, characterized in that The formula of the flow regulation function is: Wherein, L2 is the target upper limit flow rate, f(·) is the flow rate adjustment function, L1 is the preset upper limit flow rate, P2 and P1 are the actual pressure value and the preset pressure value respectively, and C is the preset coefficient.

4. The method according to claim 2, characterized in that: When, within a preset time after the target upper limit flow rate is determined to be zero, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than or equal to a fourth preset threshold value and less than or equal to a second preset threshold value; The step of adjusting the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate also includes: Recalculate the target upper limit flow rate according to the flow adjustment function; Wherein, the second preset threshold is less than or equal to the first preset threshold, and the fourth preset threshold is less than the second preset threshold; and / or, when, within a preset time after the target upper limit flow rate is determined to be zero, the actual pressure value is less than the preset pressure value, and the absolute value of the difference is greater than the second preset threshold value; The step of adjusting the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate also includes: The preset upper limit flow rate is determined as the target upper limit flow rate.

5. The method according to claim 1, characterized in that The PID control method is used to control the switch proportional valve of the gas delivery system in real time according to the target upper limit flow rate and the actual flow rate value to complete the flow control of the gas delivery system, including: Calculating a flow error according to the target upper limit flow and the actual flow value; The flow error is used as the input variable of the position PID controller, and the opening of the switch proportional valve is used as the output variable of the position PID controller. The position PID controller is used to control the opening of the switch proportional valve in real time to complete the flow control of the gas delivery system.

6. The method according to any one of claims 1 to 5, characterized in that: A flow sensor is provided at the gas outlet of the gas delivery system. Before obtaining the actual flow value at the gas outlet of the gas delivery system in real time, the method further includes: The flow sensor is calibrated.

7. The method according to claim 6, characterized in that The calibrating the flow sensor comprises: Obtain the maximum allowable flow rate of the gas delivered by the gas delivery system, and The allowable flow rate is used to obtain a plurality of continuous allowable flow ranges of the gas delivery system; In each of the flow allowable ranges, using the gas delivery system, delivering gas to the gas outlet according to a plurality of fitting flow rates, and using the flow sensor, respectively acquiring a flow acquisition signal at each of the fitting flow rates; In each of the allowable flow ranges, curve fitting is performed based on all the fitting flow rates and the flow acquisition signals under all the fitting flow rates, and flow conversion equations of the flow sensor in each of the allowable flow ranges are obtained to complete the calibration of the flow sensor.

8. A flow control system for a gas delivery system, wherein the gas delivery system is provided with a switch proportional valve; characterized in that: A flow control method for a gas delivery system according to any one of claims 1 to 7, the system comprising: A real-time pressure acquisition module, used to acquire the actual pressure value at the gas outlet of the gas delivery system in real time; An upper limit flow rate adjustment module is used to adjust the preset upper limit flow rate of the gas delivered by the gas delivery system in real time according to the actual pressure value and the preset pressure value to obtain a target upper limit flow rate; A real-time flow acquisition module, used to acquire the actual flow value at the gas outlet of the gas delivery system in real time; The flow feedback control module is used to use the PID control method to perform real-time control on the switch proportional valve of the gas delivery system according to the target upper limit flow and the actual flow value, so as to complete the flow control of the gas delivery system.

9. A flow control device for a gas delivery system, characterized in that: The method comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein the computer program implements the method steps as claimed in any one of claims 1 to 7 when executed.

10. A computer storage medium, characterized in that: The computer storage medium comprises: at least one instruction, which implements the method steps according to any one of claims 1 to 7 when the instruction is executed.

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