Automatic calibration method of electronic APL valve and anaesthesia machine

Abstract

The invention provides an automatic calibration method for an electronic APL valve and an anaesthesia machine. The method comprises the steps that a stepping motor is controlled to rotate towards an extreme point; acquiring position voltage information once every first set time, and judging whether a pointer reaches an extreme point or not according to the slope of a voltage change curve; and identifying and recording the extreme point voltage. The method has the advantages that the zero point and the maximum value point of the electronic APL valve of the anaesthesia machine can be quickly calibrated, the angle error of the pointer is prevented, and the motor is prevented from being damaged.

Description

Technical Field

[0001] The present application belongs to the technical field of anesthesia machines, and specifically relates to an automatic calibration method of an electronic APL valve and an anesthesia machine. Background Art

[0002] The electronic APL valve in the anesthesia machine is used to limit the maximum airway pressure in the manual ventilation mode of the anesthesia machine to prevent high airway pressure from causing harm to the patient. There are two types of APL valves: mechanical and electronically controlled. The mechanical valve requires manual rotation of the knob on the APL valve to the target value according to the scale. When the pressure exceeds the value indicated by the scale, the APL valve will automatically exhaust air outside the circuit and stabilize the pressure near this value. The function of the electronic APL valve is the same as that of the mechanical APL valve, but there is no need to manually rotate the knob on the valve. You only need to set the protection pressure value on the screen. The electronic APL valve will receive the target command and automatically adjust the stepper motor to the target position.

[0003] like Figure 1 The following is the system schematic diagram of the electronic APL. After the target pressure value is set on the screen, it will be transmitted to the main control board. The main control board converts the target pressure value into an angle value and uses the control signal to control the stepper motor to drive the APL valve to rotate. The angle position of the rotation is measured using a potentiometer. When the APL valve rotates, it drives the potentiometer pointer to rotate, thereby changing the voltage output by the potentiometer. After receiving the voltage signal, the main control board 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 a set minimum and maximum position when rotating, which is determined by mechanical limit stops, such as Figure 1 The two mechanical limits A and B can limit the rotation of the APL valve and the potentiometer pointer. Due to mechanical manufacturing and installation errors, there are errors in the position of the limit AB, which will cause the AB limit position on each electronic APL valve to be different. When the AB limits are different, the voltages corresponding to the zero point and maximum point of the potentiometer will be different, and the main control board needs to use the zero point voltage, maximum point voltage, and current voltage to convert the current angle position, so this part of the error will cause two problems:

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

[0006] 2. When the motor needs to rotate to the zero point or the maximum point, it may stop before reaching the target position, or continue to rotate forward when it has reached the target position. At this time, the rotation will be restricted by the mechanical limit, causing the stepper motor to stall and vibrate, resulting in voltage feedback signal jitter (such as Figure 2 Long-term operation will cause the motor to burn out. Summary of the invention

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

[0008] In order to achieve the above objectives, the present application proposes an automatic calibration method for an electronic APL valve, comprising:

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

[0010] Step S2: collecting position voltage information once at a first set time interval, and judging whether the pointer reaches an extreme point according to the slope of the voltage change curve;

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

[0012] As an improvement of the above method, judging whether the pointer reaches the extreme point according to the slope of the voltage change curve includes:

[0013] Each time the position voltage information is collected, the position curve slope k is calculated by first-order linear fitting of the information collected n times before:

[0014]

[0015] Among them, v i represents the voltage information of the ith position in the information collected in the previous n times; t i Indicates the time point of the i-th information among the previous n collected information; and are the average values ​​of the time point and position voltage information collected for the previous n times;

[0016] When the absolute value of k is less than or equal to the set threshold, it is judged that the pointer reaches the extreme point.

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

[0018] The position voltage information is collected once at every second set time interval;

[0019] When the extreme point is a 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 a 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 of the above method, the process of obtaining the voltage minimum point is as follows: the data is first in a continuous decreasing state, and when the data increases, the previous data can be determined to be a local minimum point;

[0022] The process of obtaining the voltage maximum point is as follows: the data is first in a continuous rising state, and when the data drops, the previous data can be determined to be a local maximum point.

[0023] As an improvement to the above method, the value range of n is 8-16.

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

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

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

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

[0028] The present application also provides an anesthesia machine, which uses the above method to calibrate the electronic APL valve.

[0029] Compared with the prior art, the advantages of this application are:

[0030] The method of the present application can quickly calibrate the zero point and the maximum value point of the electronic APL valve of the anesthesia machine, prevent pointer angle errors, and prevent motor damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is the system schematic diagram of the electronic APL;

[0032] Figure 2 Shown is a schematic diagram of voltage feedback signal jitter;

[0033] Figure 3 Shown is a flow chart of the automatic calibration method for the electronic APL valve. DETAILED DESCRIPTION

[0034] The technical solution of the present application is described in detail below with reference to the accompanying drawings.

[0035] like Figure 3 As shown, in response to the above problems of the existing electronic APL valve, the present application provides an automatic calibration method for an electronic APL valve, including calibration of the zero point and 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 reaches the zero point;

[0039] The position voltage information is collected every 100ms, and the position voltage information queue v = {v1, v2, v3…v n}, and its corresponding time point y={t1,t2,t3…t n}; the value range of n is 8-16, preferably 10.

[0040] Each time the position voltage information is collected, the slope k of the position voltage curve is calculated by first-order linear fitting of the queue information:

[0041]

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

[0043] When the APL runs to the zero 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 jitters rapidly, and it is then determined that it has reached the zero point.

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

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

[0046] The method for determining the minimum point is as follows: the data is first in a continuous decline state, and when the data rises, it can be determined that the previous data is a local minimum point.

[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 reaches the maximum point;

[0050] The position voltage information is collected every 100ms, and the position information voltage queue v = {v1, v2, v3…v n}, the corresponding time point t={t1,t2,t3…t n}; the value range of n is 8-16, preferably 10.

[0051] Each time the position voltage information is collected, the slope k of the position voltage curve is calculated by first-order linear fitting of the queue information:

[0052]

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

[0054] When the APL reaches the maximum point and conflicts with the mechanical limit, causing the potentiometer pointer to shake, the slope k of the position voltage information will change. When |k|≤0.2, it is considered that the potentiometer pointer shakes rapidly, and at this time it is determined to have reached the maximum point.

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

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

[0057] The method for determining the maximum point is as follows: the data is first in a continuous rising state, and when the data drops, the previous data can be determined to be a local maximum point.

[0058] When the voltages at the zero point and the maximum point are recorded, the calibration is completed, and the position voltage can be correctly converted into the angular position information after it is obtained subsequently.

[0059] The present application also provides an anesthesia machine, which uses the above method to calibrate the electronic APL valve.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application is described in detail with reference to the embodiments, a person skilled in the art should understand that any modification or equivalent replacement of the technical solution of the present application does not depart from the spirit and scope of the technical solution of the present application and should be included in the scope of the claims of the present application.

Claims

1. An automatic calibration method for an electronic APL valve, comprising: Step S1: Control the stepper motor to rotate toward the extreme point; Step S2: collecting position voltage information once at a first set time interval, and judging whether the pointer reaches an extreme point according to the slope of the voltage change curve; Step S3: Identify and record the extreme point voltage.

2. The automatic calibration method of the electronic APL valve according to claim 1 is characterized in that: The step of judging whether the pointer reaches the extreme value point according to the slope of the voltage change curve includes: Each time the position voltage information is collected, the position curve slope k is calculated by first-order linear fitting of the information collected n times before: Among them, v i represents the voltage information of the ith position in the information collected in the previous n times; t i Indicates the time point of the i-th information among the previous n collected information; and are the average values ​​of the time point and position voltage information collected for the previous n times; When the absolute value of k is less than or equal to the set threshold, it is judged that the pointer reaches the extreme point.

3. The automatic calibration method of the electronic APL valve according to claim 1 is characterized in that: The step S3 comprises: The position voltage information is collected once at every second set time interval; When the extreme point is a 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 a 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.

4. The automatic calibration method of the electronic APL valve according to claim 3 is characterized in that: The process of obtaining the minimum value point of voltage is as follows: the data is first in a continuous decreasing state, and when the data increases, the previous data can be determined to be a local minimum value point; The process of obtaining the voltage maximum point is as follows: the data is first in a continuous rising state, and when the data drops, the previous data can be determined to be a local maximum point.

5. The automatic calibration method of the electronic APL valve according to claim 2 or 3, characterized in that: The value range of n is 8-16.

6. The automatic calibration method of the electronic APL valve according to claim 2 or 3, characterized in that: The value of n is 10.

7. The automatic calibration method of the electronic APL valve according to claim 2, characterized in that: The threshold is set to 0.

2.

8. The automatic calibration method of the electronic APL valve according to claim 2, characterized in that: The first set time is 100ms.

9. The automatic calibration method of the electronic APL valve according to claim 3, characterized in that: The second set time is 1 ms.

10. An anesthesia machine, characterized in that: The anesthesia machine uses the method described in any one of claims 1-9 to calibrate the electronic APL valve.

Images