Design Of An Intelligent Monitoring System For Medical Infusion Heating Based On STM32

Medical devices are transforming and upgrading to digital and intelligent,and "medical + artificial intelligence" has become a research hotspot in the medical field today and in the future.In clinical infusion,in order to improve the comfort and safety of patients,the infusion device needs to be intelligently designed.It can meet the needs of heating the liquid in the infusion tube under different flow rates and tube diameters,the precise control of the infusion speed,and the effective detection of bubbles in the infusion tube.However,the current transfusion heating system cannot fully meet the needs of these functions,and the traditional methods cannot achieve the intelligence of transfusion heating monitoring system.Combined with the development of intelligent monitoring system for infusion heating at home and abroad,this paper studies and designs an intelligent monitoring system for infusion heating,which integrates infusion heating monitoring,infusion speed monitoring and bubble detection in infusion pipe.It also provides a good man-machine interaction and alarm function.The main research contents are summarized as follows:(1)Aiming at the needs of ordinary intravenous infusion with small flow and rapid infusion with large flow,according to the theory of infusion heating and heat transfer,the fluid solid coupling research of infusion heating temperature field is carried out,and the intelligent monitoring system architecture for infusion heating based on STM32 and two heating schemes with different infusion needs are proposed: for low-flow and low-speed intravenous infusion,the method of wrapping a long-distance silica gel heating hose at the bottom of the infusion tube is adopted;for high-flow and high-speed infusion,the method of rapid heating of the upper infusion tube and long-distance heat preservation of the lower infusion tube is adopted.The mechanism of the peristaltic infusion pump alternately extruding and releasing the elastic infusion tube to complete the liquid transportation is studied.At the same time,the ultrasonic V-shaped time difference method is proposed to detect the infusion speed.In view of the situation that small flow intravenous infusion is easy to produce bubbles,the ultrasonic bubble detection method is used to accurately detect the bubble size in the infusion tube.(2)With the STM32 microprocessor as the core module,the hardware design of temperature monitoring module,infusion speed monitoring module,bubble detection module in infusion tube,man-machine interaction module,alarm module and power module of infusion monitoring system is completed.A spiral groove fast heating device and a bidirectional thyristor constant temperature control circuit are designed for fast heating of large flow infusion.A flexible silicone heating tube heating device and a PWM signal driven MOS tube on-off temperature control circuit are designed for precise heating of small flow infusion.The heating efficiency under different infusion conditions is improved.Using tdc-gp21 chip,the speed detection circuit of infusion is designed,which can accurately measure the time difference between two ultrasonic transducers.Using the structure of ultrasonic transducer relative placement,the ultrasonic detection circuit of bubbles in the infusion tube is designed to complete the detection of bubble size in the infusion tube.(3)Based on Keil software development environment,the design process of infusion monitoring system software is studied.According to the principle of bidirectional thyristor voltage regulation,the fuzzy PID infusion constant temperature control algorithm is studied.By adjusting the output voltage to control the output power of heating,the infusion heating accuracy is ensured.In order to detect the infusion speed,the SPI port clock of the speed detection unit is configured to communicate with stm32F407,and the downstream time and countercurrent time of ultrasonic time difference method are obtained.The accurate calculation of the actual infusion speed is completed by formula conversion.In order to ensure the safety of infusion,the bubble detection module is designed to detect whether there are bubbles in the infusion tube every 0.5s,and make alarm and stop infusion according to the accumulation of bubbles.The man-machine interface of the infusion heating monitoring system is designed by using visual TFT software.The correctness of the system program is tested through the on-line debugging and simulation debugging of the industrial serial port screen and Keil software.(4)The experimental platform of infusion heating monitoring system was constructed,and the measurement accuracy of infrared temperature sensor,the accuracy of infusion temperature and infusion speed detection and control,and the effect of bubble detection in infusion tube were verified respectively.The experimental results show that the measurement accuracy of the temperature sensor is ±0.1℃,the liquid temperature input into the patient’s body is in the range of 35℃～41℃,and the infusion temperature control accuracy is ±0.5℃,which meets the comfort requirements;At the same time,it can realize the output flow of 0～200ml/min in different grades,with an accuracy of 5%;it can effectively detect bubbles larger than 0.1ml in the infusion tube;at the same time,it provides a good man-machine interface,audible alarm and other functions,which are safe,stable and reliable.