Design Of An Ultrasonic Wind Velocity Measurement System Based On STM32

With the development of science and technology,more and more fields need accurate information of wind.Due to the importance of wind speed and direction,various wind instruments have been emerged.Ultrasonic anemometer is one of them.The system which uses the characteristics of ultrasonic wave to measure the wind speed and direction has the advantages of high precision,quick current response,anti-interference,etc.,and can meet the requirements of practical application in certain fields.In this paper,after the investigating of various ultrasonic anemometer at home and abroad,the time-difference method has been selected as the main principle of this system.And the embedded platform consisted of STM32 microprocessor is used in the ultrasonic wind velocity measurement system.In this paper,the measurement system is divided into two parts:hardware and software.1.The hardware design is based on the modular manner,and the STM32 microprocessor which controls every peripheral circuit is the core of this embedded system.The transducers send out the ultrasonic signal through the drive circuit.The receiving circuit serves for amplifying and filtering the pulse signal.The system can access the historical data from the memory cell,and communicates externally with the serial communication circuit.2.The software is designed by the method of structured-programming language,and it is based on ?C/OS-?-an embedded real-time operating system,which can take each hardware module under control.In this part,the wind vector is calculated by the propagation time of the ultrasonic signal.The function of data storage and transmission is also included in this part.Finally,the prototype testing and debugging has been carried out in the wind tunnel.After analyzing the measurement data,the results show that the accuracy of wind speed can reach to±0.2m/s(wind speed ? 35m/s)or ±2%(wind speed>35m/s)and wind direction can reach to ±2.5°.So,the measurement system can achieve the requirements of engineering applications.It can also provide all-weather measurement in most conditions,and has an extensive application for the wind measurement.