A Pulse Wave Acquisition Pressure Control Method, Device and System

Abstract

The present application relates to a pulse wave acquisition pressure control method, device and system, belonging to the field of pulse measurement technology, and is used for technical problems such as high power consumption and inability to continuously and real-time monitor the pulse in the prior art. The method includes: determining the current pulse acquisition pressure; controlling a pump-valve integrated air pump to inflate the airbag with a first duty cycle; when the air pressure in the airbag reaches the current pulse acquisition pressure, determining a second duty cycle according to a preset mapping relationship, where the preset mapping relationship is the corresponding relationship between the duty cycle and the pulse acquisition pressure; controlling the pump-valve integrated air pump to inflate the airbag with the second duty cycle; and adjusting the current duty cycle in real time based on the second duty cycle to maintain the air pressure in the airbag within the neighborhood of the current pulse acquisition pressure. The technical solution provided by the present application can reduce the power consumption of the device and continuously and real-time monitor the pulse.

Description

[0001] Technical Field

[0002] This application belongs to the technical field of pulse measurement, and particularly relates to a pulse wave acquisition pressure control method, device, and system. Background Art

[0003] Pulse waves contain rich and important physiological information of the human body. Therefore, scientific pulse diagnosis auxiliary equipment has become a research direction in recent years.

[0004] Currently, most devices at home and abroad are mainly large-scale pulse diagnosis devices, which are suitable for traditional Chinese medicine auxiliary detection for doctors. The pressurization method of large-scale pulse diagnosis devices is mainly stagewise pressurization. Through the pump-valve separation scheme, an air pump is driven to achieve pressurization, and a solenoid valve is closed to stabilize the gas in the airbag.

[0005] However, when the same scheme is applied to the airbag of small devices such as smart bracelets, it will cause high power consumption, large volume, inconvenient to carry, and cannot meet the requirements of continuous real-time pulse monitoring, portability, and low power consumption. Summary of the Invention

[0006] In view of the above analysis, this application aims to propose a pulse wave acquisition pressure control method, device, and system to solve at least one of the above technical problems.

[0007] The objectives of this application are mainly achieved through the following technical solutions:

[0008] In a first aspect, this application provides a pulse wave acquisition pressure control method, including:

[0009] Determine the current pulse acquisition pressure;

[0010] Control the pump-valve integrated air pump to inflate the airbag with a first duty cycle;

[0011] When the air pressure in the airbag reaches the current pulse acquisition pressure, determine a second duty cycle according to a preset mapping relationship, where the preset mapping relationship is the corresponding relationship between the duty cycle and the pulse acquisition pressure;

[0012] Control the pump-valve integrated air pump to inflate the airbag with the second duty cycle;

[0013] Real-time adjust the current duty cycle based on the second duty cycle, and maintain the air pressure in the airbag within the neighborhood of the current pulse acquisition pressure.

[0014] Further, the pump-valve integrated air pump includes: an air outlet air path;

[0015] The real-time adjustment of the current duty cycle based on the second duty cycle to maintain the air pressure in the airbag within the neighborhood of the pulse acquisition pressure includes:

[0016] Detect whether the current pulse acquisition pressure is within the neighborhood;

[0017] When the current pulse acquisition pressure is within the neighborhood, determine that the current duty cycle remains unchanged;

[0018] When the current pulse acquisition pressure is not within the neighborhood, update the current duty cycle according to the preset PID parameters;

[0019] When the updated duty cycle is greater than the current duty cycle, the air pressure in the airbag increases;

[0020] When the updated duty cycle is less than the current duty cycle, the air pressure in the airbag decreases.

[0021] Further, the pump-valve integrated air pump includes: an intake air path and an exhaust air path;

[0022] The real-time adjustment of the current duty cycle based on the second duty cycle to maintain the air pressure in the airbag within the neighborhood of the pulse acquisition pressure includes:

[0023] By adjusting the current duty cycle in real time, control the difference between the intake rate of the intake air path and the exhaust rate of the exhaust air path.

[0024] Further, the intake air path and the exhaust air path are connected;

[0025] The control of the difference between the intake rate of the intake air path and the exhaust rate of the exhaust air path by adjusting the current duty cycle in real time includes:

[0026] When increasing the air pressure in the airbag, increase the current duty cycle and control the intake rate of the intake air path to be greater than the exhaust rate of the exhaust air path;

[0027] When reducing the air pressure in the airbag, reduce the current duty cycle and control the intake rate of the intake air path to be less than the exhaust rate of the exhaust air path;

[0028] When maintaining the air pressure in the airbag unchanged, maintain the current duty cycle unchanged and control the intake rate of the intake air path to be equal to the exhaust rate of the exhaust air path.

[0029] Further, an exhaust switch is provided at the exhaust end;

[0030] The control of the difference between the intake rate of the intake air path and the exhaust rate of the exhaust air path further includes:

[0031] When the intake rate of the intake air path increases, increase the switching frequency of the exhaust switch;

[0032] When the intake rate of the intake air path decreases, the switching frequency of the outlet switch is decreased.

[0033] In a second aspect, an embodiment of the present invention provides a pulse wave acquisition pressure control device, including: an acquisition module, a first control module, a data processing module, and a second control module;

[0034] The acquisition module is configured to determine the pulse acquisition pressure;

[0035] The first control module is configured to control the air pressure in the airbag to reach the pulse acquisition pressure with a first duty cycle;

[0036] The data processing module is configured to determine a second duty cycle according to a preset mapping relationship, where the preset mapping relationship is a corresponding relationship between the second duty cycle and the pulse acquisition pressure;

[0037] The second control module is configured to maintain the air pressure in the airbag within a neighborhood of the pulse acquisition pressure by adjusting the second duty cycle in real time.

[0038] In a third aspect, an embodiment of the present invention provides a pulse wave acquisition pressure control system, including: the device described in the second aspect and an integrated pump-valve air pump;

[0039] The device is configured to execute the method described in the first aspect.

[0040] Further, the integrated pump-valve air pump includes a buffer chamber, an intake air path, an outlet air path, and a motor;

[0041] One end of the buffer chamber is connected to the airbag, and the other end is connected to the intake air path and the outlet air path;

[0042] The other end of the intake air path is connected to the motor;

[0043] The other end of the outlet air path is connected to the atmosphere.

[0044] Further, an outlet switch is provided at one end of the outlet air path connected to the atmosphere, and the outlet switch is opened or closed at a preset switching frequency.

[0045] Further, the outlet switch includes: a rotating shaft and a fan blade;

[0046] The fan blade is sleeved on the rotating shaft.

[0047] Compared with the prior art, the present application can at least achieve one of the following technical effects:

[0048] 1. After the air pressure in the airbag reaches the pulse acquisition pressure, based on the pump-valve integrated air pump structure, the duty cycle of the motor is adjusted through the PID algorithm to precisely adjust the gas pressure in the airbag, thereby achieving real-time regulation of the pressure in the airbag.

[0049] 2. Use the air outlet gas path of the pump-valve integrated air pump to make the gas output per unit time and the generated air pressure deviation of the same order of magnitude. Then, use the buffer chamber to further reduce the gas entering or leaving the airbag per unit time, providing technical support for fine-tuning the gas volume in the airbag.

[0050] 3. The pulse wave acquisition pressure control method provided by this application has good accuracy, and the error rate can be controlled below 0.2%.

[0051] 4. Replace the solenoid valve with the air outlet gas path to reduce the power consumption of the device.

[0052] Other features and advantages of this application will be described in the subsequent specification, and some will be obvious from the specification, or understood by implementing this application. The objectives and other advantages of this application can be achieved and obtained through the structures specifically pointed out in the written specification and the accompanying drawings. Brief Description of the Drawings

[0053] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to this application. Throughout the drawings, the same reference signs represent the same components.

[0054] Figure 1 It is a flowchart of a pulse wave acquisition pressure control method provided by an embodiment of this application;

[0055] Figure 2 It is a schematic structural diagram of a bracelet for measuring pulse provided by an embodiment of this application;

[0056] Figure 3 It is a schematic structural diagram of a pump-valve integrated air pump provided by an embodiment of this application;

[0057] Figure 4 It is a schematic structural diagram of another pump-valve integrated air pump provided by an embodiment of this application;

[0058] Figure 5 It is a schematic diagram of the detection result of Embodiment 1 provided by an embodiment of this application;

[0059] Figure 6 It is a schematic diagram of the detection result of Embodiment 2 provided by an embodiment of this application;

[0060] Figure 7 It is a schematic diagram of the detection result of Embodiment 3 provided by an embodiment of this application;

[0061] Figure 8 Schematic diagram of the control result of Embodiment 4 provided by the embodiment of the present application;

[0062] Figure 9 Schematic diagram of the measurement result of Embodiment 4 provided by the embodiment of the present application;

[0063] Figure 10 PID flowchart of Embodiment 4 provided by the embodiment of the present application;

[0064] Figure 11 Flowchart of a pulse acquisition method provided by the embodiment of the present application. Detailed implementation manners

[0065] The preferred embodiments of the present application will be specifically described below with reference to the accompanying drawings. The accompanying drawings form a part of the present application and are used together with the embodiments of the present application to explain the principle of the present application, rather than to limit the scope of the present application.

[0066] The pulse wave contains rich and important physiological information of the human body. These physiological information include but are not limited to pulse position, pulse force, pulse rate, rhythm, tensility, and fluency. If you want to accurately obtain the above measurement parameters, it is necessary to collect the physiological information within a period of time and then calculate its average value.

[0067] When measuring the pulse, usually use an airbag to wrap the human wrist and apply pressure to the wrist through the airbag to obtain the pulse. In the prior art, first, the pressure in the airbag reaches a preset pressure, then the inflation stops, and the pulse measurement starts. However, the above method has the following problems:

[0068] 1. The process of airbag expansion will affect the measurement of the pressure inside the airbag by the sensor. Specifically, the inflation of the airbag is a process. When the airbag stops expanding, the test result of the pressure inside the bag is stable. However, in the prior art, the air pressure is usually measured in the inflated state, and at this time, the airbag has not completed expansion, which will cause deviation in the air pressure measurement value.

[0069] 2. The degree of airbag expansion will affect the measurement of the pressure inside the airbag by the sensor. Specifically, when measuring, the airbag will wrap the wrist. And when the human body feels pain or itching, it will instinctively adjust the posture of the wrist, which will cause the originally stopped expanding airbag to continue to expand or even contract, thus changing the air pressure.

[0070] 3. Once the pressure inside the airbag reaches the preset value range, the inflation will stop. At this time, if the air pressure fluctuates slightly due to Problem 1 and Problem 2, whether to choose inflation or deflation, it is very difficult to ensure that the air pressure reaches the preset value. At this time, adjusting the air pressure will waste a lot of time, and not adjusting will lead to inaccurate measurement results.

[0071] 4. In the prior art, a solenoid valve is only used to release the gas in the airbag. Although it is convenient for automatic control, it increases the power consumption. In actual use, for a bracelet worn on the wrist, the entire bracelet is powered by a battery. As Figure 2 shown, the bracelet mainly includes a display screen, a bracelet switch, an airbag, and a pulse sensor. Obviously, in this scenario, it is very difficult for the battery power to meet the power consumption of the solenoid valve.

[0072] To solve the above technical problems, the present application adopts a pump-valve integrated air pump as shown in Figure 3 shown. The pump-valve integrated air pump includes: a buffer chamber 301, an intake air passage 302, an exhaust air passage 303, and a motor 304. One end of the buffer chamber 301 is connected to the airbag, and the other end is respectively connected to the intake air passage 302 and the exhaust air passage 303. The other end of the intake air passage 302 is connected to the motor 304; the motor inputs the introduced gas into the intake air passage. Specifically, the motor controls the intake rate through the duty cycle. The other end of the exhaust air passage 302 is connected to the atmosphere. During operation, in order to facilitate the control of the air pressure in the airbag, the intake air passage 302 and the exhaust air passage 303 work simultaneously. It can be seen that the above device needs to continuously ventilate, so there is no measurement error generated by Problem 1. Moreover, by adjusting the duty cycle of the motor 304 and cooperating with the buffer chamber 301, the amount of gas entering the airbag can be well controlled, so that the air pressure in the airbag is stabilized near a certain pressure value. Therefore, it provides a prerequisite for solving Problems 2 and 3. When the motor 304 stops working, the gas in the airbag can be automatically discharged from the exhaust air passage 303, solving the problem of large power consumption of the solenoid valve. Optionally, the number of exhaust air passages can be multiple, such as 2. It should be noted that in the prior art, the solenoid valve is designed on the airbag and is independent of the air pump. In the present application, the exhaust air passage 303 functions as a solenoid valve and is provided on the air pump. Therefore, in order to distinguish it from the prior art, the air pump used in the present application is denoted as a pump-valve integrated air pump.

[0073] Preferably, in order to facilitate the control of the air pressure in the airbag, an exhaust switch is provided at the end of the exhaust air passage 303 connected to the atmosphere. When the intake rate of the intake air passage increases, the switching frequency of the exhaust switch is increased to prevent the airbag from expanding too fast; when the intake rate of the intake air passage decreases, the switching frequency of the exhaust switch is decreased to prevent the airbag from contracting too fast.

[0074] Preferably, the exhaust switch includes: a rotating shaft and a fan blade. The fan blade is sleeved on the rotating shaft, and the rotating shaft is arranged at the end of the exhaust air passage 303 connected to the atmosphere. In this way, the airflow flowing out of the airbag can drive the exhaust switch to open or close at a specific frequency to achieve the automatic operation of the exhaust switch without additionally increasing circuits and control components. For example, when the gap between the fan blades is aligned with the air outlet of the exhaust air passage, it is equivalent to the switch being closed and the air passage being closed. When a single fan blade is aligned with the air outlet of the exhaust air passage, it is equivalent to the switch being open and the air passage being open.

[0075] Specifically, the present application provides a pump-valve integrated air pump as Figure 4 shown. O is the mounting hole through which the airbag is connected; M is the drive motor; C is the gas buffer chamber with a side length of approximately 5 mm, which plays a role in gas buffering; S1 and S2 are two continuously rotating valves respectively arranged at two air outlets. Then the pipeline between C and M constitutes the intake air path, and the pipelines between C - S1 and C - S2 constitute the outlet air paths.

[0076] Based on the above pump-valve integrated air pump, an embodiment of the present application provides a method for controlling the pressure for pulse wave acquisition, including the following steps:

[0077] Step 1: Determine the pulse acquisition pressure.

[0078] In the embodiment of the present application, the specific process of Step 1 is as follows: Place the pulse wave sensor and the signal enhancement structure (such as a linear amplifier circuit) at the wrist pulse beating position. After collecting a certain amount of data, release a synchronization signal to start the corresponding algorithm to analyze the physiological parameters based on the collected data. Adjust the pressing force through the pressure control algorithm. After quickly pressurizing the air pressure to 60 mmHg, start slow pressurization to ensure that enough data is collected for analysis. Then, based on the collected data, analyze and obtain the static pressure point where the pulse wave is the clearest, and this pressure point is the pulse acquisition pressure. Preferably, the pulse wave acquisition sensor is a 10 mm × 40 mm single-point type.

[0079] Step 2: Control the pump-valve integrated air pump to inflate the airbag with a first duty cycle.

[0080] In the embodiment of the present application, usually increase the air pressure in the airbag to the pulse acquisition pressure at the maximum power. Therefore, usually use the duty cycle corresponding to the maximum power as the first duty cycle.

[0081] Step 3: When the air pressure in the airbag reaches the pulse acquisition pressure, determine a second duty cycle according to the preset mapping relationship.

[0082] In the embodiment of the present application, the preset mapping relationship is the corresponding relationship between the duty cycle and the pulse acquisition pressure. The process of determining the preset mapping relationship is as follows: Determine a plurality of objects to be measured and a plurality of pulse acquisition pressures to be measured. Then, for each object to be measured, respectively determine the corresponding duty cycle at each pulse acquisition pressure to be measured, and this duty cycle can maintain the pulse acquisition pressure for a period of time. Finally, respectively obtain the average value of the duty cycles corresponding to each pulse acquisition pressure to be measured, and the obtained average value is the duty cycle corresponding to each pulse acquisition pressure to be measured. The corresponding relationship between the plurality of pulse acquisition pressures to be measured and the duty cycle is the preset mapping relationship. According to this preset mapping relationship, determine that the duty cycle corresponding to the pulse acquisition pressure in step 1 is the second duty cycle. It should be noted that when the motor operates at the second duty cycle, the air pressure in the airbag is basically stable.

[0083] Specifically, use 60 mmHg, 70 mmHg, 80 mmHg, 90 mmHg, 100 mmHg, 110 mmHg, 120 mmHg, 130 mmHg, 140 mmHg, and 150 mmHg as the pulse acquisition pressures to be measured, and select 30 objects to be measured. Taking the measurement of the duty cycle of 60 mmHg as an example, for each object to be measured, use the same device to determine the corresponding duty cycle under the condition that the pulse acquisition pressure of 60 mmHg is stable for 30 seconds. Then, take the average value of the 30 duty cycles corresponding to 60 mmHg as the duty cycle corresponding to 60 mmHg. Preferably, for each pulse acquisition pressure to be measured, each object to be measured is measured 3 times. The duty cycles corresponding to other values of the pulse acquisition pressures to be measured are all obtained according to the above method. Then, according to the obtained pulse acquisition pressures and duty cycles, obtain a plurality of data points (pressure, duty cycle), and finally, perform linear fitting according to the plurality of data points to obtain the mapping relationship between the pulse acquisition pressure and the duty cycle.

[0084] Step 4: Control the pump-valve integrated air pump to inflate the airbag at the second duty cycle.

[0085] Step 5: Real-time adjust the current duty cycle based on the second duty cycle. By real-time adjusting the second duty cycle, maintain the air pressure in the airbag within the neighborhood of the pulse acquisition pressure.

[0086] As described above, Problem 1 and Problem 2 lead to measurement deviations, and Problem 3 leads to the inability to correct the deviations. The parameter directly related to the duty cycle is the unit gas output. The larger the duty cycle, the larger the gas output per unit time. And the gas output per unit time determines the pressure change in the airbag. Usually, the larger the gas output per unit time, the greater the pressure increase in the airbag. Therefore, the crux of Problem 3 lies in that the deviations caused by Problem 1 and Problem 2 and the gas output are usually not in the same order of magnitude. For example, the deviations caused by Problem 1 and Problem 2 require increasing or decreasing at most dozens of milliliters of gas, while for practical application considerations, the minimum unit gas output of the motor per unit time is usually several hundred milliliters.

[0087] In the embodiment of the present application, in combination with the pump-valve integrated air pump and the PID algorithm in the above embodiment, by adjusting the second duty cycle in real time, the difference between the intake rate of the intake air path and the exhaust rate of the exhaust air path is controlled to solve Problems 1-3.

[0088] Specifically, it is detected whether the current pulse acquisition pressure is within the neighborhood. When the current pulse acquisition pressure is within the neighborhood, it is determined that the current duty cycle remains unchanged. In the embodiment of the present application, the neighborhood refers to the allowable interval range of the change in the pulse acquisition pressure. When the current pulse acquisition pressure is not within the neighborhood, the current duty cycle is updated according to the preset PID parameters. When the updated duty cycle is greater than the current duty cycle, the air pressure in the airbag increases. When the updated duty cycle is less than the current duty cycle, the air pressure in the airbag decreases.

[0089] It should be noted that in the embodiment of the present application, the control idea of PID is to use the difference between the currently collected air pressure value and the pulse acquisition pressure as the input to adjust the air pressure so that it stabilizes within no more than 3% floating up and down around the optimal air pressure value. After 30 seconds of starting PID, the current PID process ends and all parameters are initialized to before starting.

[0090] Furthermore, when increasing the air pressure in the airbag, the current duty cycle is increased to control the intake rate of the intake air path to be greater than the exhaust rate of the exhaust air path. When reducing the air pressure in the airbag, the current duty cycle is decreased to control the intake rate of the intake air path to be less than the exhaust rate of the exhaust air path. When maintaining the air pressure in the airbag unchanged, the current duty cycle is maintained unchanged to control the intake rate of the intake air path to be equal to the exhaust rate of the exhaust air path.

[0091] It can be seen from this that the present application uses the exhaust air path of the pump-valve integrated air pump to make the unit gas output per unit time and the deviations of Problem 1 and Problem 2 in the same order of magnitude. Then, by using the buffer chamber, the gas entering or flowing out of the airbag per unit time is further reduced, providing technical support for fine-tuning the gas volume in the airbag. Finally, the PID algorithm is used to regulate the duty cycle, thereby realizing fine-tuning of the gas volume in the airbag.

[0092] An embodiment of the present application provides a pulse wave acquisition pressure control device, including: an acquisition module, a first control module, a data processing module, and a second control module;

[0093] The acquisition module is used to determine the pulse acquisition pressure;

[0094] The first control module is used to control the air pressure in the airbag to reach the pulse acquisition pressure with a first duty cycle;

[0095] The data processing module is used to determine a second duty cycle according to a preset mapping relationship, where the preset mapping relationship is the corresponding relationship between the second duty cycle and the pulse acquisition pressure;

[0096] The second control module is used to maintain the air pressure in the airbag within the neighborhood of the pulse acquisition pressure by adjusting the second duty cycle in real time.

[0097] An embodiment of the present application provides a pulse wave acquisition pressure control system, including: a pulse wave acquisition pressure control device and a pump-valve integrated air pump. The pulse wave acquisition pressure control device can execute the pulse wave acquisition pressure control method described in the present application. For the structure of the pump-valve integrated air pump, reference is made to Figure 3 and Figure 4 ; for the functions of each structure, reference is made to Figure 3 and Figure 4 the corresponding embodiments.

[0098] In addition, the system of the embodiment of the present application further includes: a pressure sensor, a data transmission structure, a display structure, and a signal enhancement structure.

[0099] The pressure sensor is arranged in the airbag and is used to collect the air pressure in the airbag.

[0100] The data transmission structure is mainly composed of a serial port and Bluetooth, and is mainly used to transmit the pulse wave electrical signal collected by the pulse wave sensor and the air pressure electrical signal collected by the pressure sensor to the upper computer or mobile phone through the serial port or Bluetooth, so as to facilitate users or doctors to observe the data; at the same time, it will also transmit the physiological data calculated by the algorithm.

[0101] The display structure uses a 1.54-inch ink screen to display physiological information in real time.

[0102] The signal enhancement structure is specifically a linear signal amplification circuit, which is used to amplify and stabilize the collected signal.

[0103] Among them, a bionic silica gel material is placed between the wrist pulse and the pulse wave sensor for collection, so that the collected pulse wave waveform is clearer.

[0104] Preferably, the barometric pressure sensor used in this application has good repeatability and long-term working stability, including but not limited to the MPS20N0040D-S sensor. It has the following characteristics: ① small size of 7mm x 7mm. To meet the portability requirement, the sensor should not occupy too much space; ② operating temperature range of -40°C to 125°C; ③ measurement range of 0 to 40KPa, which can meet the measurement range of blood pressure monitors.

[0105] Preferably, the nRF52810 Bluetooth chip is adopted. Through the design of the transmission protocol, it ensures the characteristics of distortion-free data transmission and retransmission in case of timeout. At the same time, this structure has extremely low power consumption, meeting the low-power requirement of the bracelet system.

[0106] An embodiment of the present invention provides a pulse acquisition method as Figure 11 shown

[0107] Step S1: Initialize the system and peripherals.

[0108] Step S2: Search for the pulse acquisition pressure.

[0109] Step S3: Determine whether the pulse acquisition pressure is found. If yes, execute Step S4; otherwise, execute Step S8.

[0110] Step S4: Analysis stage. Pressurize to the pulse acquisition pressure, stabilize the air pressure for 30s, and determine the physiological information.

[0111] Step S5: Determine whether the air pressure is stable within 30s. If yes, execute Step S6; otherwise, execute Step S7.

[0112] Step S6: Output the physiological information and return Finish.

[0113] Step S7: Use PID regulation to stabilize the air pressure and return to Step S4.

[0114] Step S8: Return Failed, the start button can be activated to re-measure, and return to Step S1.

[0115] Among them, Steps S1 and S8 include: initialization of RTOS (Real Time Operating System), air pump initialization, screen initialization, Bluetooth initialization, ADC (analog to digital converter) initialization, TIM (timer) initialization, serial port initialization, and interrupt initialization. Step S1 specifically is:

[0116] RTOS initialization, that is, the initialization of the operating system used, is used to create each task and the semaphore for controlling task scheduling, and allocate the corresponding memory space for each task and semaphore.

[0117] The air pump motor is initialized, combined with TIM initialization, TIM1 of MCU (Microcontroller Unit) is used as PWM (Pulse Width Modulation) output, and the full duty cycle value is 1000 / 1000. The duty cycle of the pump-valve integrated air pump during the initialization stage is 0 / 1000.

[0118] Initialize the screen, refresh the screen to white (do not display any pattern), prepare the dynamic array of the screen to display the image, then just change the value of the dynamic array and print it on the screen to display the pattern.

[0119] Bluetooth initialization uses but is not limited to the nRF52810 low-power Bluetooth chip, combined with MCU serial port 2 and Bluetooth serial port initialization. The baud rate of MCU serial port 2 and Bluetooth serial port initialization is 115200. The two serial ports on the PCB are connected to realize data transmission between the MCU and the Bluetooth chip. According to the self-defined data transmission protocol stack (the frame header and frame tail are added to the front and back ends of the data to be transmitted each time, and it is determined whether it is this frame header and frame tail during reception. If so, it is valid data) to ensure that data transmission is not distorted.

[0120] After Bluetooth receives the data from the MCU, it divides the data into the corresponding number of packets. The data of a Bluetooth transmission packet is 244 bytes, and the maximum amount of data transmitted per second is 80KB. The number of packets required is determined according to the size of the data received from the serial port. For example, in this system, the data size transmitted from the MCU to Bluetooth per second is 2030 bytes. After Bluetooth receives it, it will be divided into 10 packets, and the frame header, frame tail and location data of each packet will be defined and transmitted to the host computer or mobile phone.

[0121] ADC is initialized and is responsible for data collection. 10-channel ADC collects data and stores the data of the air pressure sensor and pulse wave sensor in the buffer after averaging for future data analysis.

[0122] TIM initialization, in addition to TIM1 mentioned in the air pump motor initialization, TIM2 is also used as a timer. Combined with the semaphore initialized by RTOS, TIM2 sets the interrupt period to 0.04s. The semaphore is released during the interrupt to collect, analyze and display data, so 250 data points can be collected within 1s; TIM3 is used to refresh the gatedog during the interrupt, and TIM4 is used to detect whether the entire system process is completed during the interrupt. After the end signal is received, all variables will be initialized.

[0123] Serial port initialization: The baud rates of MCU serial port 1, serial port 2, and the Bluetooth serial port are all 115,200. MCU serial port 2 and the Bluetooth serial port are as described above. MCU serial port 1 is used to send data to the host computer for display. The data transmitted by serial port 1 and Bluetooth is the same.

[0124] Interrupt initialization: As in the above TIM initialization, it also includes MCU serial port 1 initialization, which is used to detect whether the commands input at the serial port are valid. In addition, it includes the interrupt initialization necessary for the MCU system.

[0125] It should be noted that the above initializations are only the RTOS initialization as the system initialization, and the rest are peripheral initializations.

[0126] Steps S2 - S4 include: ADC acquisition, algorithm analysis, Bluetooth transmission, and screen display. The specific processes of steps S2 - S7 refer to steps 1 - 5.

[0127] To prove the feasibility of the above solution, the following embodiments are given in this application:

[0128] Embodiment 1

[0129] Under the condition that the airbag pressure is 0, the duty cycle corresponding to the maximum power is taken as the first duty cycle, the internal pressure of the airbag is increased to the pulse acquisition voltage of 100 mmHg, and then the duty cycle of 251 / 1000 is taken as the second duty cycle, and the detection result as shown in Figure 5 is obtained. The obtained pulse acquisition voltage is 100.15 mmHg, and the error rate is 0.15%.

[0130] Embodiment 2

[0131] Under the condition that the airbag pressure is 0, the duty cycle corresponding to the maximum power is taken as the first duty cycle, the internal pressure of the airbag is increased to the pulse acquisition voltage of 100 mmHg, and then the duty cycle of 259 / 1000 is taken as the second duty cycle, and the detection result as shown in Figure 6 is obtained. The obtained pulse acquisition voltage is 107.39 mmHg, and the error rate is 7.3%.

[0132] Embodiment 3

[0133] Under the condition that the airbag pressure is 0, the duty cycle corresponding to the maximum power is taken as the first duty cycle, the internal pressure of the airbag is increased to the pulse acquisition voltage of 100 mmHg, and then the duty cycle of 250 / 1000 is taken as the second duty cycle, and the detection result as shown in Figure 7 is obtained. The obtained pulse acquisition voltage is 96.45 mmHg, and the error rate is 3.55%.

[0134] As can be seen from Examples 1-3, the technical solution provided by the present application can stably control the pulse acquisition voltage by controlling the duty cycle, and the error rate can be controlled below 0.2%.

[0135] Example 4

[0136] Assume that the current pulse acquisition voltage is 100 mmHg. Under the condition that the airbag pressure is 0, the duty cycle corresponding to the maximum power is taken as the first duty cycle. The internal pressure of the airbag is increased to the pulse acquisition voltage of 100 mmHg, and then the duty cycle of 251 / 1000 is taken as the second duty cycle. Combining with the PID algorithm, the pulse acquisition voltage is maintained at 100 mmHg within 30 s to collect the pulse wave electrical signal. Among them, the PID algorithm parameters are: the proportional value is 5-15 (for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, preferably 10), the integral value is 0, and the differential value is 1. The specific process of PID is as Figure 10 shown. Among them, the initial drive voltage is the second duty cycle, the data collected by the pressure sensor is the actual airbag pressure at present, and the difference between the actual pressure and the expected output is used as the input of the PID algorithm; in the final output, the input corresponding to the proportional coefficient is the current error, the input corresponding to the integral coefficient is the cumulative error (an array is required to calculate the cumulative error in the code), and the input corresponding to the differential coefficient is the difference between this error and the previous error.

[0137] The control results and measurement results of Example 4 are as Figure 8 and Figure 9 shown, Figure 8 is the change of the pulse acquisition voltage within 30 s, Figure 9 is the change of the pulse wave electrical signal within 30 s. As can be seen from Figure 8 , the pulse acquisition voltage is stable at 100 mmHg within 30 s. As can be seen from Figure 9 , the pulse wave electrical signal is clear and stable within 30 s, without mutation and overlap. In summary, the technical solution provided by the present application can accurately stabilize the pulse acquisition voltage at a certain value, which is the optimal voltage value for collecting the pulse wave electrical signal, so as to achieve clear and stable pulse wave electrical signals.

[0138] The above is only the preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the technical field of the present application within the technical scope disclosed by the present application should be covered by the protection scope of the present application.

Claims

1. A method for controlling the pressure of pulse wave acquisition, characterized in that, Based on a pump-valve integrated air pump, the pump-valve integrated air pump includes a buffer chamber, an intake air passage, an exhaust air passage, and a motor; one end of the buffer chamber is connected to an airbag, and the other end is connected to one end of the intake air passage and one end of the exhaust air passage; the other end of the intake air passage is connected to the motor, and the other end of the exhaust air passage is connected to the atmosphere; the motor inputs the introduced gas into the intake air passage, and the intake air passage and the exhaust air passage work simultaneously; The method includes: Determine the pulse collection pressure; Control the pump-valve integrated air pump to inflate the airbag with a first duty cycle; When the air pressure in the airbag reaches the pulse collection pressure, determine a second duty cycle according to a preset mapping relationship, where the preset mapping relationship is the corresponding relationship between the duty cycle and the pulse collection pressure; Control the pump-valve integrated air pump to inflate the airbag with the second duty cycle; Taking the second duty cycle as a reference, adjust the current duty cycle of the motor in real time, and cooperate with the buffer chamber to control the amount of gas entering the airbag, and maintain the air pressure in the airbag within the neighborhood of the pulse collection pressure.

2. The method according to claim 1, wherein The taking the second duty cycle as a reference, adjusting the current duty cycle of the motor in real time, cooperating with the buffer chamber to control the amount of gas entering the airbag, and maintaining the air pressure in the airbag within the neighborhood of the pulse collection pressure includes: Detect whether the air pressure in the airbag is within the neighborhood; When the air pressure in the airbag is within the neighborhood, determine that the current duty cycle remains unchanged; When the air pressure in the airbag is not within the neighborhood, update the current duty cycle according to the preset PID parameters; When the updated duty cycle is greater than the current duty cycle, the air pressure in the airbag increases; When the updated duty cycle is less than the current duty cycle, the air pressure in the airbag decreases.

3. The method according to claim 1, wherein The taking the second duty cycle as a reference, adjusting the current duty cycle of the motor in real time, cooperating with the buffer chamber to control the amount of gas entering the airbag, and maintaining the air pressure in the airbag within the neighborhood of the pulse collection pressure includes: By adjusting the current duty cycle in real time, control the difference between the intake rate of the intake air passage and the exhaust rate of the exhaust air passage.

4. The method according to claim 3, wherein The intake air passage and the exhaust air passage are connected; The by adjusting the current duty cycle in real time to control the difference between the intake rate of the intake air passage and the exhaust rate of the exhaust air passage includes: When increasing the air pressure in the airbag, increase the current duty cycle and control the intake rate of the intake air passage to be greater than the exhaust rate of the exhaust air passage; When reducing the air pressure in the airbag, reduce the current duty cycle and control the intake rate of the intake air passage to be less than the exhaust rate of the exhaust air passage; When maintaining the air pressure in the airbag unchanged, maintain the current duty cycle unchanged and control the intake rate of the intake air passage to be equal to the exhaust rate of the exhaust air passage.

5. The method according to claim 4, wherein An exhaust switch driven by the airflow flowing out of the airbag is provided at one end of the exhaust air passage connected to the atmosphere; Controlling the difference between the intake rate of the intake air passage and the outlet rate of the outlet air passage further includes: When the intake rate of the intake air passage increases, increasing the switching frequency of the outlet switch; When the intake rate of the intake air passage decreases, decreasing the switching frequency of the outlet switch.

6. A pulse wave acquisition pressure control system, characterized in that, It includes: A pulse wave acquisition pressure control device and an integrated pump-valve air pump; the integrated pump-valve air pump includes a buffer chamber, an intake air passage, an outlet air passage, and a motor; one end of the buffer chamber is connected to the airbag, and the other end is connected to one end of the intake air passage and one end of the outlet air passage; the other end of the intake air passage is connected to the motor, and the other end of the outlet air passage is connected to the atmosphere; the motor inputs the introduced gas into the intake air passage, and the intake air passage and the outlet air passage work simultaneously; The device is used to execute the method according to claims 1-5; it includes: a collection module, a first control module, a data processing module, and a second control module; The collection module is used to determine the pulse collection pressure; The first control module is used to control the air pressure in the airbag to reach the pulse collection pressure at a first duty cycle; The data processing module is used to determine a second duty cycle according to a preset mapping relationship, and the preset mapping relationship is the corresponding relationship between the second duty cycle and the pulse collection pressure; The second control module is used to adjust the current duty cycle of the motor in real time based on the second duty cycle, cooperate with the buffer chamber, control the amount of gas entering the airbag, and maintain the air pressure in the airbag within the neighborhood of the pulse collection pressure.

7. The system according to claim 6, wherein One end of the outlet air passage connected to the atmosphere is provided with an outlet switch driven by the airflow flowing out of the airbag, and the outlet switch is opened or closed at a preset switching frequency.

8. The system according to claim 6, wherein The outlet switch includes: a rotating shaft and a fan blade; The fan blade is sleeved on the rotating shaft.

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