Disclosure of Invention
In order to solve the problems, the disclosure provides a portable emergency ventilator and a control method thereof, which select a centrifugal fan more suitable for CPR, provide a larger gas flow rate under the condition of lower airway pressure, avoid the occurrence of air pressure injury during CPR, provide a new thought for the design of a novel portable emergency ventilator for CPR during OHAC, and have important guiding significance for emergency treatment such as cardiopulmonary resuscitation.
According to some embodiments, a first aspect of the present disclosure provides a portable emergency ventilator, which adopts the following technical scheme:
a portable emergency ventilator, comprising:
The air inlet of the direct current brushless fan is communicated with the air-oxygen mixer, and the air outlet of the direct current brushless fan is communicated with one end of the automatic ball valve;
One end of the first connecting pipeline is communicated with one end of the automatic ball valve far away from the brushless fan side, and the other end of the first connecting pipeline is communicated with the flow sensor;
the second connecting pipeline is communicated with the first connecting pipeline through the flow sensor, and a pressure sensor is arranged on the second connecting pipeline;
and the controller is respectively and electrically connected with the direct-current brushless fan, the automatic ball valve, the flow sensor and the pressure sensor.
As a further technical definition, the portable emergency ventilator further comprises a power supply unit electrically connected to the controller, the direct current brushless fan, the automatic ball valve, the flow sensor and the pressure sensor wires, respectively.
As a further technical limitation, the automatic ball valve comprises a motor, a first bearing, a first valve body, a valve core, a second valve body, a second bearing and an angle sensor, wherein the valve core is fixed in the first valve body and the second valve body through the first bearing and the second bearing, the motor is connected with the valve core through the first bearing, and the angle sensor is connected with the valve core through the second bearing.
Further, the motor is connected with the air outlet of the direct-current brushless fan, and the angle sensor is connected with the first connecting pipeline.
The angle sensor is connected with the valve core, acquires the rotation angle of the valve core in real time, feeds back the acquired valve core angle to the controller, combines the pressure sensor and the flow sensor to form a closed loop control system of the valve core, and adjusts the motor in real time so that the valve core rotates by a proper angle.
Further, in the closed-loop control system, the flow sensor acquires the flow of the first communication pipeline to the second communication pipeline in real time and feeds real-time data back to the controller, the controller combines the real-time data and preset flow data to control the direct-current brushless fan in real time to complete the real-time adjustment of the flow of the portable emergency ventilator, and the motor is adjusted under the action of the controller to control the rotation angle of the automatic ball valve according to the real-time control of the direct-current brushless fan and the real-time monitoring of the flow sensor, so that the opening and closing states of the automatic ball valve are controlled.
According to some embodiments, a second aspect of the present disclosure provides a method for controlling a portable emergency ventilator, which adopts the following technical scheme:
A method of controlling a portable emergency ventilator, comprising:
acquiring real-time data of a pressure sensor and a flow sensor to obtain initial flow and ventilation frequency of the portable emergency breathing machine;
And according to the obtained initial flow and ventilation frequency, the direct-current brushless fan is regulated in real time by combining with a controller, so that the real-time regulation of the portable emergency ventilator is realized.
The method is characterized by comprising the steps of combining a controller to regulate a direct current brushless fan in real time, adopting a wavelet transformation optimization PID control method, namely an MR-PID control algorithm, dividing an input signal into a low-scale signal for eliminating noise, a middle-scale signal for increasing damping and a high-scale signal for eliminating high-frequency distortion under the action of the controller based on the MR-PID control algorithm, combining the three signals to generate a smooth control signal, and realizing real-time regulation of the portable emergency ventilator.
As a further technical definition, the real-time adjustment of the portable emergency ventilator includes respiratory rate adjustment and respiratory flow adjustment;
In the respiratory rate adjusting process, the rotating angle of the valve core is obtained in real time through an angle sensor, the obtained valve core angle is fed back to the controller, a closed-loop control system of the valve core is formed by combining the pressure sensor and the flow sensor, a motor is adjusted in real time, the rotating angle of the automatic ball valve is controlled, the valve core is enabled to rotate by a proper angle, the opening and closing state of the automatic ball valve is controlled, and the respiratory rate of the portable emergency ventilator is adjusted;
In the process of respiratory flow regulation, the flow of the first communication pipeline to the second communication pipeline is obtained in real time through a flow sensor, real-time data are fed back to the controller, the direct-current brushless fan is regulated in real time by combining the real-time monitoring data of the pressure sensor and the flow sensor, the flow of the air inlet of the direct-current brushless fan is regulated, and the regulation of the respiratory flow of the portable emergency ventilator is completed.
As a further technical limitation, in the process of real-time regulation of the portable emergency ventilator, an S-T titration mode is adopted to construct a linear relation between PWM of the direct-current brushless fan and the maximum airway flow of the portable emergency ventilator, so that the initial PWM is predicted, and the titration speed of the portable emergency ventilator is improved.
Compared with the prior art, the beneficial effects of the present disclosure are:
the portable emergency breathing machine based on volume control is simple in structure and small in size, a fan with low airway pressure and high flow is used as a gas pressurizing source, the portable emergency breathing machine is more suitable for emergency treatment during CPR, air pressure injury is avoided, a brushless direct current motor control method is used for realizing accurate control of flow of the portable emergency breathing machine, meanwhile, a novel S-T titration method is used, simplicity and effectiveness are achieved, titration can be achieved through ventilation twice, and titration time is greatly shortened.
Detailed Description
The disclosure is further described below with reference to the drawings and examples.
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments in accordance with the present disclosure. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, are merely relational terms determined for convenience in describing structural relationships of the various components or elements of the present disclosure, and do not denote any one of the components or elements of the present disclosure, and are not to be construed as limiting the present disclosure.
In the present disclosure, terms such as "fixedly coupled," "connected," "coupled," and the like are to be construed broadly and refer to either a fixed connection or an integral or removable connection, or both, as well as directly or indirectly via an intermediary. The specific meaning of the terms in this disclosure may be determined according to circumstances by a person skilled in the relevant art or a person, and is not to be construed as limiting the disclosure.
Embodiments of the present disclosure and features of embodiments may be combined with each other without conflict.
Example 1
The embodiment of the disclosure introduces a breathing machine, designs a novel portable emergency breathing machine, provides required ventilation through a direct-current brushless fan, captures air passage flow through a flow sensor, sends pulse width modulation (Pulse width modulation, PWM) signals to perform feedback adjustment on the rotating speed of the direct-current brushless fan through a microprocessor to complete a constant volume ventilation mode, realizes frequency adjustment of the portable emergency breathing machine through an automatic ball valve, improves response speed of the portable emergency breathing machine, and completes mixing of air and oxygen through a simple air-oxygen mixer to meet the requirement of preset oxygen content.
The portable emergency breathing machine shown in fig. 1 comprises a first connecting pipeline 1, an automatic ball valve 2, an air-oxygen mixer 3, a direct-current brushless fan 4, a controller 5, a power supply unit 6, a flow sensor 7, a pressure sensor 8 and a second connecting pipeline 9, wherein the aerodynamic force of the portable emergency breathing machine is derived from the direct-current brushless fan 4, and the speed of the aerodynamic force is regulated by using PWM signals to control the flow of an air outlet of the direct-current brushless fan 4. The air outlet of the direct current brushless fan 4 is connected with the automatic ball valve 2, and the automatic ball valve 2 is used for completing the opening and closing of the first connecting pipeline 1 and controlling the respiratory rate. The air inlet of the direct current brushless fan 4 is connected with the simple air-oxygen mixer 3, so that the mixing of oxygen and air is realized. The automatic ball valve 2 is connected with the air inlet of the flow sensor 7 through the first connecting pipeline 1, so that the flow sensor 7 monitors the air passage flow in real time, the air outlet of the flow sensor 7 is connected with the second connecting pipeline 9, and the pressure sensor 8 is connected on the second connecting pipeline 9 to capture the pressure in the air passage in real time. The controller 5 is used for receiving data of the flow sensor 7 and the pressure sensor 8, and simultaneously, performs feedback control on the direct-current brushless fan 4 to ensure the provision of constant flow. The power supply unit 6 supplies 24V voltage required for the flow sensor 7, 5V voltage required for the pressure sensor 8 and the controller 5, and 12V voltage required for the automatic ball valve 2.
As shown in fig. 2, the automatic ball valve 2 comprises a first bearing 21, a first valve body 22, a second valve body 23, an angle sensor 24, a second bearing 25, a valve core 26 and a motor 27, wherein the valve core 23 is fixed in the first valve body 22 and the second valve body 23 through the first bearing 21 and the second bearing 25, the motor 27 is connected with the valve core 26 through the first bearing 21, the angle sensor 24 is connected with the valve core 26 through the second bearing 25, the motor 27 is connected with an air outlet of the direct current brushless fan 4, and the angle sensor 24 is connected with the first connecting pipeline 1.
The frequency of the portable emergency breathing machine is cooperatively controlled by an automatic ball valve 2 and a direct current brushless fan 4, a valve body is composed of an upper valve body 2 and a lower valve body 3, a valve core 6 is installed in the valve body, the valve core 6 is fixed in the valve body through a first bearing 1 and a second bearing 5, the bearing ensures free rotation of the valve core, a motor 7 provides power for rotation of the valve core 6, so that the valve core 6 rotates to open and close a pipeline, an angle sensor 4 is connected with the valve core 6 to obtain the rotation angle of the valve core 6, and a closed loop system is formed by the angle sensor 4 and a miniature stepping motor 7 to ensure that the valve core rotates by a correct angle.
In the using process of the portable emergency breathing machine, a motor 27 is connected with a valve core 26 to provide power for rotating the valve core 26, opening and closing of a first communication pipeline 1 are achieved, an angle sensor 24 is connected with the valve core 26 to acquire the rotating angle of the valve core 26 in real time, the acquired angle of the valve core 26 is fed back to a controller 5, a closed-loop control system of the valve core 26 is formed by combining a pressure sensor 8 and a flow sensor 7, the motor 27 is adjusted in real time, the valve core 26 rotates by a proper angle, in the closed-loop control system, the flow sensor 7 acquires the flow of a first communication pipeline 1 to a second communication pipeline 9 in real time and feeds the real-time data back to the controller 5, the controller 5 combines the real-time data and preset flow data to conduct real-time control on a direct-current brushless fan 4, the motor is adjusted under the action of the controller 5 according to the real-time control on the direct-current brushless fan 4, and the rotating angle of the automatic ball valve 2 is controlled, and the automatic ball valve 2 is controlled to realize the control on the opening and closing states of the automatic ball valve 2.
Example two
The second embodiment of the disclosure introduces a control method of the portable emergency ventilator based on the first embodiment, eliminates input signal noise by a multi-resolution proportional-integral-derivative (MR-PID) algorithm, completes real-time control of the airway flow of the portable emergency ventilator, completes precise control of respiratory rate, inspiration time and expiration time by using a direct-current brushless fan and an automatic ball valve, and completes titration process by adopting an S-T titration mode through fewer ventilation times. The optimal initial PWM value can be predicted through the flow parameter and the PWM parameter of the previous two times, so that the initial flow reaches the preset flow, the titration time is reduced, and the titration speed of the portable emergency breathing machine is improved.
The control method of the portable emergency ventilator shown in fig. 3 comprises the steps of controlling the flow and the breathing frequency of a system, acquiring the initial flow and the ventilation frequency by the portable emergency ventilator, acquiring the initial PWM value by S-T titration, driving a direct current brushless fan, and enabling the portable emergency ventilator to enter a gas suction phase after an automatic ball valve is opened. The portable emergency breathing machine records flow and time parameters in real time in the ventilation process, judges whether the inspiration time is reached, judges whether the target flow is reached or not if the expiration time is not reached, adjusts PWM values to control the outlet flow of the direct current brushless fan if the target flow is not reached, jumps out of the inspiration phase into the expiration phase after the expiration time is reached, closes the automatic ball valve, simultaneously receives the expiration PWM to reduce the rotating speed, and enters the expiration phase again when the expiration time reaches the preset expiration time.
As shown in the control structure block diagram of the inspiration flow and the respiration frequency of the portable emergency ventilator shown in fig. 4, the flow of the portable emergency ventilator is read through a flow sensor, meanwhile, the read actual flow Fr is fed back to a controller, and the controller compares the actual flow Fr with the preset flow Fs to complete the real-time control of the PWM value required by the direct-current brushless fan, so that the flow of the portable emergency ventilator is regulated in real time. The breathing frequency of the portable emergency breathing machine is adjusted by controlling the inspiration time and expiration time of the portable emergency breathing machine, the time parameters of actual ventilation, including the air inlet time and expiration time Tr, are read through the direct-current brushless fan, meanwhile, the actual time Tr and the preset time Ts are compared and judged by the controller, the automatic ball valve is opened and closed, and the automatic ball valve is provided with a feedback system of the automatic ball valve to ensure that the valve is completely opened and completely closed.
In the embodiment, the direct-current brushless fan adopts an MR-PID control method, and wavelet transformation is used for optimizing PID control on a PID algorithm, so that accurate control on the pre-reference flow is realized.
The multi-resolution nature of the wavelet transform has good resolution in both the time and frequency domains. He is a hierarchical representation of the signal or function presented in successive approximation on different scales. Each approximation is a smoothed version of the original signal. Error resolution allows detailed information of different frequencies to be captured according to the number of resolution levels. In an MR-PID controller, the error signal is decomposed into a linear combination of basis functions consisting of a mother wavelet and its expansion and translation by utilizing the multi-resolution characteristic of the wavelet, and has good resolution in both the time and frequency domains.
The MR-PID control method shown in fig. 5 uses wavelet transformation to divide the error signal into high, medium and low frequencies. The corresponding increase in gain of the high frequency signal improves the interference rejection of the device. The intermediate frequency signal is damped in the device to improve transient characteristics, the low frequency signal eliminates noise by adjusting the noise to zero, and by combining the three, a smooth control signal can be generated to meet the required characteristics.
In fig. 5, R, Y and e are a reference signal, an output signal, and an error signal, respectively. The error signal e is used as the linear combination of orthogonal functions, is decomposed into various components by wavelet, is transformed and combined to generate a control signal u, and is decomposed into high and low repeated parts at a certain decomposition level.
The error decomposition components of the low frequency are:
the error decomposition component of the intermediate frequency is:
the error decomposition components of the high frequency are:
Where N is a horizontal number and N and k are integer sets.
Filters h [ k ] and g [ k ] are specific illustrations of selected wavelet functions. The MR-PID controller has further sub-gains at different frequencies between the highest frequency and the lowest frequency by three gain parameters KH、KM、KL.KM at high, medium and low frequencies, depending on the resolution level and the desired accuracy. More decomposition levels increase the number of these sub-benefits. But at least two levels of decomposition are required due to the three gains involved. In the patent, two-stage decomposition is used, since the application of the two-stage decomposition brings about good results. However, more levels may be used for higher accuracy, but at the cost of higher computational complexity.
In terms of frequency, the proportional and integral terms are used to capture the low frequency signal, while the derivative term is used to capture the high frequency signal. In an MR-PID controller, the error signal is decomposed into its high, low and medium frequencies, namely:
e(X)=eH(X)+eM1(X)+…+eM(n-1)(X)+eL(X)
scaling each error component according to the respective gain to generate a controller output signal uMP-PID, which is obtained:
uMP-PID＝KHeH+KM1eM1+…+KM(n-1)eM(n-1)+KLeL
The control output of the MR-PID controller is a linear combination of different gains, and these components can be scaled by the corresponding gains to generate the control signal.
The present embodiment uses two-stage decomposition to obtain a controller with three tuning parameters. Some of the disturbances in the control of the motor are low frequency signals and the noise generated in the sensor is high frequency signals. MR-PID controllers perform better than PID controllers. In multi-resolution decomposition, the signal is split into low-scale, mid-scale and high-scale error signals. The high scale signal is used to cancel high frequency distortion and the increase in gain corresponding to the high scale signal improves interference rejection of the device. The mesoscale signal adds damping in the device to improve its transient characteristics, the low scale signal eliminates noise by adjusting the noise to zero, and by combining the three, a smooth control signal can be generated to meet the desired characteristics.
In order to obtain the titration of the fast V-IPPV mode, a new S-T titration method is adopted in the embodiment, and the optimal initial expiration PWM value can be obtained after two complete titration and ventilation. The S-T titration method is shown in fig. 5, the portable emergency breathing machine randomly starts ventilation for the first time by a PWM signal, the portable emergency breathing machine records a PWM value PWM1 and a maximum actual flow Fr1 of the ventilation for the first time, the portable emergency breathing machine also records a PWM value of a centrifugal fan as PWM2 and a maximum actual flow Fr2 in the ventilation for the second time, and the portable emergency breathing machine searches the most suitable initial expiration PWM value Pini through the PWM1, the PWM2, the Fr1 and the Fr2 captured in the previous two times after ventilation for the second time. The PWM value Pini is used for the expiration phase of the portable emergency ventilator with the automatic ball valve closed, and the initial flow in the inspiration phase is ensured to reach the preset requirement quickly.
At a fixed PWM, the maximum airway flow for a single ventilation is proportional to the PWM value after the portable emergency ventilator is connected to the simulated lung. The S-T titration method uses the linear relation of PWM and maximum flow (Pini= (PWM 2-PWM 1)/(Fs 2-Fs 1)/(Fs-Fs 2) +PWM 2), and the optimal initial expiration PWM value Pini can be accurately predicted by using the ventilation parameters of the previous two times.
According to the embodiment, the initial flow and the ventilation frequency of the portable emergency ventilator are obtained by acquiring the real-time data of the pressure sensor and the flow sensor, and the DC brushless fan is regulated in real time by combining a controller according to the obtained initial flow and ventilation frequency, so that the real-time regulation of the portable emergency ventilator is realized, wherein the real-time regulation of the portable emergency ventilator comprises regulation of the breathing frequency and regulation of the breathing flow;
in the process of adjusting the respiratory rate, acquiring the rotating angle of the valve core in real time through an angle sensor, feeding the acquired valve core angle back to the controller, combining a pressure sensor and a flow sensor to form a closed-loop control system of the valve core, adjusting a motor in real time, controlling the rotating angle of an automatic ball valve, enabling the valve core to rotate by a proper angle, controlling the opening and closing state of the automatic ball valve, and realizing the adjustment of the respiratory rate of the portable emergency ventilator;
In the process of respiratory flow regulation, the flow of the first communication pipeline to the second communication pipeline is obtained in real time through the flow sensor, real-time data are fed back to the controller, the direct-current brushless fan is regulated in real time by combining the real-time monitoring data of the pressure sensor and the flow sensor, the flow of the air inlet of the direct-current brushless fan is regulated, and the regulation of the respiratory flow of the portable emergency ventilator is completed.
The foregoing description of the preferred embodiments of the present disclosure is provided only and not intended to limit the disclosure so that various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.
While the specific embodiments of the present disclosure have been described above with reference to the drawings, it should be understood that the present disclosure is not limited to the embodiments, and that various modifications and changes can be made by one skilled in the art without inventive effort on the basis of the technical solutions of the present disclosure while remaining within the scope of the present disclosure.