Design Of Control System For Portable Air Permeability Instrument

With the rapid growth of the economy and the improvement of people’s living standards,the national awareness of healthy living is also strengthening,and the comfort of the fabric has also put forward higher requirements.The comfort of fabrics mainly includes breathability,moisture permeability,and thermal conductivity,and the excellent breathability of fabrics will directly affect the comfort of people wearing them.At present,most of the fabric permeability instruments on the market are large desktop styles,which are generally large in size and heavy in mass,not easy to carry and carry,and the test can only be completed offline.In response to these problems,this study is interested in reducing the cost of portable air permeability instruments,simplifying program development,designing microprocessor-based Micro Python program development,and developing a small,lightweight,portable air permeability instrument to achieve mobile measurement of fabrics both online and offline.This design mainly implements the following.Firstly,design the overall structure,control scheme,and testing method of the portable air permeability instrument according to the testing principle,objectives,and requirements of textile fabric breathability,and design the whole testing process scheme according to the overall structure and testing method of the air permeability instrument.Secondly,according to the overall structure and control scheme,design the hardware system of the control system of the portable air permeability instrument,select the sensor data acquisition module and the PWM control module of the extractor fan and the display module,and the power supply module according to the characteristics and performance of the main control chip STM32F405,and design in detail the communication connection between each module and the main control as well as the circuit implementation.Thirdly,design the Micro Python software control program based on the STM32F405 development board based on the measurement method and testing principle of the portable air permeability instrument.Design the sensor differential pressure acquisition,PID program control output PWM extractor fan speed control,program results display,by running the Python language on the microprocessor,using an object-oriented approach to design the program architecture,the program is highly readable,easy to expand,easy to debug.Fourth,debugging operation of the whole control system.According to the national standard GB/T 5453-1997 "textile fabric air permeability determination" for six test samples,the actual test results are compared with the fixed YG461 E air permeability,and the average error value accuracy is less than ±2%mm/s by calculating the specimens,which meets the requirements of the national standard.It shows that this portable air permeability instrument control system has good stability.The portable air permeability instrument designed in this paper improves the accuracy of testing air permeability by using a magnetic suction structure to fix the test fabric.There are fewer portable instruments at home and abroad,so this breaks the monopoly of domestic and foreign markets,and at the same time realizes mobile testing,increases the efficiency of textile testing,and improves product quality.