Research Of Wind Measurement System Based On Hexcopter

With the development of human society,a flexible and relatively low-cost instrument is needed to measure the wind field at high altitudes.This paper proposes a method for direct wind measurement based on a multi-rotor unmanned aerial vehicle(MUAV)platform equipped with a wind measurement instrument.Aiming at the shortcomings of previous studies,this method uses wind tunnel tests,field measurements,data post-processing and other aspects to comprehensively examine accuracy of the wind measurement method,and to analyze its feasibility.(1)The research status of wind measurement based on MUAVs is elaborated in detail.The related theories and research results are summarized,and the deficiencies and limitations in previous studies are also analyzed.According to the wind measurement method based on the MUAVs,the integration and modification of instruments were performed to develop a practical and usable overall drone wind measurement system.(2)An ultrasonic anemometer is attached on a hexacopter using different height brackets,and wind tunnel test is carried out to investigate the influence of rotor rotation on the wind field at different heights above the center of the hexacopter and the influence of different wind direction and tilted fuselage on the measurement accuracy.The test results show that the hexacopter itself has little effect on the incoming wind speed.And when the turbulent intensity of the incoming flow is not large,the rotation of the rotor will not have a great impact on the calculated turbulent intensity;rotor rotation has almost no influence on the measurement of the wind direction angle.(3)In order to further analyze the feasibility of wind measurement based on the MUAV platform,a field measurement study is carried out.The wind speed and direction data measured by MUAV wind measurement system at 40 m height are compared with the data collected by a wind measurement tower,and the results show that the time history of wind direction measured by the two methods is in good agreement except for the error caused by placement directions and some scattered outliers.(4)After the attitude correction of wind speed data,the calibration with wind tower and the wind direction correction,the relative error of average wind speed and component wind speed can be controlled within ± 2%.At the same time,the low-pass filter method and the moving average method are used to process the wind speed data.The results show that the two methods have similar effects and can play a role in smoothing noise and eliminating some abnormal data,but they can also reduce the calculated turbulent intensity in all directions.In comparison,the moving average method is more suitable for the data processing in this paper.This Studies have shown that the method of direct wind measurement by using MUAVs equipped with wind measuring instruments is feasible and can provide a reference for future related researches.