An automatic calibration method for an electronic APL valve and an anesthesia machine

Abstract

This application provides an automatic calibration method for an electronic APL valve and an anesthesia machine. The method includes: controlling a stepper motor to rotate towards an extreme point; acquiring position voltage information at first set time intervals, determining whether the pointer has reached the extreme point based on the slope of the voltage change curve; identifying and recording the extreme point voltage. The advantage of this application is that the method can quickly calibrate the zero and maximum points of the electronic APL valve of the anesthesia machine, preventing pointer angle errors and motor damage.

Description

Technical Field

[0001] This application belongs to the field of anesthesia machine technology, specifically relating to an automatic calibration method for an electronic APL valve and an anesthesia machine. Background Technology

[0002] The electronic APL valve in an anesthesia machine limits the maximum airway pressure in manual ventilation mode, preventing harm to the patient from excessive airway pressure. There are two types of APL valves: mechanical and electronic. Mechanical valves require manual rotation of a knob on the valve according to the scale to reach the target value. When the pressure exceeds the value indicated on the scale, the APL valve automatically releases air from the circuit, stabilizing the pressure to near that value. Electronic APL valves function similarly to mechanical APL valves, but do not require manual rotation of the knob. The protection pressure value is set on the screen, and the electronic APL valve receives the target command and automatically adjusts the stepper motor to the target position.

[0003] like Figure 1 The diagram shows the system schematic of an electronic APL (Automatic Pressure Valve). After the target pressure value is set on the screen, it is transmitted to the main control board. The main control board converts the target pressure value into an angle value and uses a control signal to control a stepper motor to rotate the APL valve. The rotation angle is measured using a potentiometer. When the APL valve rotates, it causes the potentiometer pointer to rotate, thus changing the voltage output of the potentiometer. The main control board receives the voltage signal, converts it into an angle position, and then converts the angle position into pressure information, which is displayed on the screen in real time.

[0004] The APL valve has set minimum and maximum positions for rotation, determined by mechanical limits, such as... Figure 1 The two mechanical limit switches, A and B, restrict the rotation of the APL valve and the potentiometer pointer. Due to manufacturing and installation errors, the positions of limit switches A and B are inaccurate, resulting in different A and B limit positions on each electronic APL valve. When the A and B limits are different, the voltages corresponding to the zero and maximum points of the potentiometer will also be different. The main control board needs to use the zero-point voltage, maximum-point voltage, and current voltage to calculate the current angle position. Therefore, this error leads to two problems:

[0005] 1. The pointer angle position information is inaccurate;

[0006] 2. When rotation to zero or maximum point is required, it may stop before reaching the target position, or continue rotating forward even after reaching the target position. In this case, the rotation will be restricted by the mechanical limit switch, causing the stepper motor to stall and vibrate, resulting in fluctuations in the voltage feedback signal (e.g., Figure 2 As shown in the image, prolonged operation can cause the motor to burn out. Summary of the Invention

[0007] The purpose of this application is to overcome the defect of inaccurate pointer angle position information of the electronic APL valve in existing anesthesia machines, which easily causes damage to the motor.

[0008] To achieve the above objectives, this application proposes an automatic calibration method for electronic APL valves, comprising:

[0009] Step S1: Control the stepper motor to rotate towards the extreme point;

[0010] Step S2: Collect position voltage information once every first set time interval, and determine whether the pointer has reached the extreme point based on the slope of the voltage change curve;

[0011] Step S3: Identify and record the extreme point voltages.

[0012] As an improvement to the above method, the step of determining whether the pointer has reached an extreme point based on the slope of the voltage change curve includes:

[0013] For each acquisition of location voltage information, the slope k of the location curve is calculated by first-order linear fitting of the information acquired in the previous n acquisitions:

[0014]

[0015] Among them, v i This represents the voltage information at the i-th location from the information collected in the previous n data acquisitions; t i This represents the time point of the i-th piece of information collected in the previous n collections. and These represent the average values ​​of the time points and location voltage information from the previous n acquisitions;

[0016] The pointer is considered to have reached an extreme point when the absolute value of k is less than or equal to the set threshold.

[0017] As an improvement to the above method, step S3 includes:

[0018] Location voltage information is collected once every second set time interval;

[0019] When the extreme point is also the minimum point, record the n local minimum points of the voltage during the oscillation process, and take the average value as the extreme point voltage;

[0020] When the extreme point is the maximum point, record the n local maximum points of the voltage during the oscillation process, and take the average value as the extreme point voltage.

[0021] As an improvement to the above method, the process of obtaining the local minimum point of voltage is as follows: the data is initially in a continuous decreasing state, and when the data rises, the previous data can be determined as the local minimum point.

[0022] The process of obtaining the voltage maximum point is as follows: the data is initially in a continuous rising state. When the data decreases, the previous data point can be determined as a local maximum point.

[0023] As an improvement to the above method, the value of n ranges from 8 to 16.

[0024] As an improvement to the above method, the value of n is 10.

[0025] As an improvement to the above method, the set threshold is 0.2.

[0026] As an improvement to the above method, the first set time is 100ms.

[0027] As an improvement to the above method, the second setting time is 1ms.

[0028] This application also provides an anesthesia machine in which the above-described method is used to calibrate the electronic APL valve.

[0029] Compared with existing technologies, the advantages of this application are:

[0030] The method described in this application can quickly calibrate the zero and maximum points of the electronic APL valve of an anesthesia machine, preventing pointer angle errors and motor damage. Attached Figure Description

[0031] Figure 1 The diagram shown is the system schematic of an electronic APL.

[0032] Figure 2 The diagram shown illustrates voltage feedback signal jitter.

[0033] Figure 3 The diagram shows the automatic calibration method for electronic APL valves. Detailed Implementation

[0034] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0035] like Figure 3 As shown, in view of the above-mentioned problems of existing electronic APL valves, this application provides an automatic calibration method for electronic APL valves, including calibration of the zero point and calibration of the maximum point of the electronic APL valve.

[0036] Zero point calibration:

[0037] Step A1: Control the stepper motor to rotate in the direction of closing the valve;

[0038] Step A2: Identify whether the mechanical limit position has reached zero;

[0039] Location voltage information is collected every 100ms, resulting in a location voltage information queue v = {v1, v2, v3…v}. n}, and its corresponding time points y={t1,t2,t3…t n The value of n ranges from 8 to 16, with 10 being preferred.

[0040] For each instance of location voltage information collected, the slope k of the location voltage curve is calculated by first-order linear fitting of the queue information:

[0041]

[0042] in, and These are the average values ​​of the time queue and the location voltage information queue, respectively.

[0043] When the APL reaches zero and conflicts with the mechanical limit, causing the potentiometer pointer to jitter, the slope k of the position voltage information will change. When |k|≤0.2, it is considered that the potentiometer pointer is jittering rapidly, which is then considered as reaching zero.

[0044] Step A3: Record the zero-point voltage information.

[0045] When the mechanical limit position is detected to have reached zero, the voltage will be in an oscillation process. At this time, the data is collected every 1ms, and the n local minimum points V of the voltage during the oscillation process are recorded. min ={V1,V2…V n}, calculate the average value of the voltage at the minimum point. Record this value as the zero-point voltage.

[0046] The method for determining the local minimum is as follows: the data is initially in a continuous decreasing state, and when the data rises, the previous data point can be identified as the local minimum.

[0047] Maximum point calibration:

[0048] Step B1: Control the stepper motor to rotate in the valve opening direction;

[0049] Step B2: Identify whether the mechanical limit position has reached its maximum point;

[0050] Location voltage information is collected every 100ms, resulting in a location voltage queue v = {v1, v2, v3…v}. n}, and its corresponding time point t={t1,t2,t3…t n The value of n ranges from 8 to 16, with 10 being preferred.

[0051] For each instance of location voltage information collected, the slope k of the location voltage curve is calculated by first-order linear fitting of the queue information:

[0052]

[0053] in, and These are the average values ​​of the time queue and the location voltage information queue, respectively.

[0054] When the APL reaches its maximum point and conflicts with the mechanical limit, causing the potentiometer pointer to jitter, the slope k of the position voltage information will change. When |k|≤0.2, it is considered that the potentiometer pointer is jittering rapidly, which is then considered as reaching the maximum point.

[0055] Step B3: Record the maximum point voltage information.

[0056] When the mechanical limit position is detected to reach its maximum point, the voltage will be in an oscillation process. At this time, data is collected every 1ms, and the n local maxima V of the voltage during the oscillation process are recorded. max ={V1,V2…V n}, calculate the average value of the voltage at the maximum point. Record this value as the maximum point voltage.

[0057] The method for determining a local maximum is as follows: if the data is initially in a continuous upward trend, and then a decline occurs, the previous data point can be identified as a local maximum.

[0058] Once the voltages at the zero and maximum points are recorded, the calibration is complete. Subsequently, the position voltages can be correctly converted into angular position information.

[0059] This application also provides an anesthesia machine in which the above-described method is used to calibrate the electronic APL valve.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application, and should all be covered within the scope of the claims of this application.

Claims

1. An automatic calibration method for an electronic APL valve, comprising: Step S1: Control the stepper motor to rotate towards the extreme point; Step S2: Collect position voltage information once every first set time interval, and determine whether the pointer has reached the extreme point based on the slope of the voltage change curve; Step S3: Identify and record the extreme point voltages; The method of determining whether the pointer has reached an extreme point based on the slope of the voltage change curve includes: For each acquisition of location voltage information, the slope k of the location curve is calculated by first-order linear fitting of the information acquired in the previous n acquisitions: Among them, v i This represents the voltage information at the i-th location from the information collected in the previous n data acquisitions; t i This represents the time point of the i-th piece of information collected in the previous n collections. and These represent the average values ​​of the time points and location voltage information from the previous n acquisitions; The pointer is considered to have reached an extreme point when the absolute value of k is less than or equal to the set threshold. Step S3 includes: Location voltage information is collected once every second set time interval; When the extreme point is also the minimum point, record the n local minimum points of the voltage during the oscillation process, and take the average value as the extreme point voltage; When the extreme point is the maximum point, record the n local maximum points of the voltage during the oscillation process, and take the average value as the extreme point voltage.

2. The automatic calibration method for the electronic APL valve according to claim 1, characterized in that, The process of obtaining the local minimum point of voltage is as follows: the data is initially in a continuous decreasing state. When the data rises, the previous data point can be determined as the local minimum point. The process of obtaining the voltage maximum point is as follows: the data is initially in a continuous rising state. When the data decreases, the previous data point can be determined as a local maximum point.

3. The automatic calibration method for the electronic APL valve according to claim 1, characterized in that, The value of n ranges from 8 to 16.

4. The automatic calibration method for the electronic APL valve according to claim 1, characterized in that, The value of n is 10.

5. The automatic calibration method for the electronic APL valve according to claim 1, characterized in that, The set threshold is 0.

2.

6. The automatic calibration method for the electronic APL valve according to claim 1, characterized in that, The first set time is 100ms.

7. The automatic calibration method for the electronic APL valve according to claim 1, characterized in that, The second set time is 1ms.

8. An anesthesia machine, characterized in that, The anesthesia machine calibrates the electronic APL valve using the method described in any one of claims 1-7.

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