The Development Of Household Noninvasive Ventilator Based On Fractional Order PID Controller

The household ventilator is a portable ventilator that can be used in the daily life.It provides noninvasive positive pressure mechanical ventilation through a mask.When the patient's respiratory tract collapses or blocks during sleep,it can provide suitable pressure to open the airway and ensure that the patient breathe smoothly.So it has good therapeutic effect on OSAHS.Domestic research on household ventilator started relatively late,lacking core technology,and the high-end ventilator market is monopolized by foreign brands.Therefore,this paper researches the core algorithm of household ventilator according to relevant standards and technical indicators,and combines fractional order PID control technology and the Internet of Things technology to design a household ventilator based on fractional order PID controller.This paper introduces the development history and research status of household ventilator,analyzes the basic principle,ventilation mode and composition of ventilator,and determines the main technical parameters and technical indicators of household ventilator referring to the relevant standards of ventilator,then develops the overall design of the household ventilator and the functional requirements of each module.The household ventilator studied in this paper uses the microcontroller STM32F407 with Cortex-M4 kernel and the ?C/OS-? real-time operating system.This paper designs the ventilator control system and intelligent alarm system,and realizes respiratory recognition and processing,data storage and communication,human-machine interaction,intelligent alarm and other functions.This paper innovatively uses a fractional order PID controller for ventilator airway pressure control.The ventilator uses a brushless DC motor as a fan to drive the surrounding air into the airway of the ventilator to achieve positive pressure ventilation treatment.The fractional order PID controller is used to control the brushless DC motor speed to adjust the pressure.Then the ventilator can provide pressure stably and reduce pressure overshoot and oscillation to improve system ventilation safety and patient comfort.At the same time,this paper studies the core algorithm of household ventilator,and adopts the respiratory process identification technology based on flow-trigger.It measures the ventilator airway flow through the sensor to identify and process the respiratory process,including mask detachment detection,leakage calculation,respiratory trigger recognition,respiratory state transition,tidal volume calculation.apnea detection,hypopnea detection,etc.The ventilator can adjust the treatment pressure according to the breathing state of the patient,so it can achieve good human-machine synchronization effect.In this paper,combined with the Internet of Things technology,the ventilator can communicate with the mobile client through bluetooth and Wi-Fi.The user can use the mobile client to monitor the ventilator,and the mobile client uploads the respiratory data to the remote medical server to achieve telemedicine monitoring and diagnosis functions.This paper designs a good human-machine interaction interface,using a LCD based on dual-core CPU,and using the configuration software for page beautification and layout,which makes it more friendly and convenient for operation.At the same time,this paper implements the ventilator intelligent alarm function based on the priority queue,which can prompt the most urgent alarm event in time,so that the patient can get safe and effective treatment.Finally,this paper tests the control effect,remote monitoring function and intelligent alarm function of the ventilator.The test results show that the household ventilator designed in this paper can meet the initial design requirements,the relevant standards and technical indicators.It can output pressure stably,with good human-machine synchronization effect,and its remote monitoring and intelligent alarm function is complete.After clinical testing,the household ventilator can be used in daily life.