{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,31]],"date-time":"2026-01-31T05:25:07Z","timestamp":1769837107064,"version":"3.49.0"},"reference-count":35,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2019,6,10]],"date-time":"2019-06-10T00:00:00Z","timestamp":1560124800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Modern orchard intelligent fine production management technology research and development","award":["2017YFD0701400"],"award-info":[{"award-number":["2017YFD0701400"]}]},{"name":"Ground and aviation efficient engineering technology and intelligent equipment","award":["2016YFD0200700"],"award-info":[{"award-number":["2016YFD0200700"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Accurate measurement of the downwash flow field of plant protection unmanned aerial vehicles (UAVs) is essential for analyzing the spatial distribution of droplets. To realize on-line rapid detection of the downwash flow field of a multi-rotor UAV, a flexible polypropylene detection device based on the principle of full bridge strain effect was proposed. Its performance principle was based on the physical deformation caused by wind pressure. The Fluid Flow and Static Structural modules of ANSYS 16.0 finite element software were used to simulate one-way fluid-solid coupling interaction. The surface of the resistive strain gauge embedded in the flexible detecting structure responded well to wind speed variation, hence it was suitable for downwash airflow wind field detection. By solving the strain force on the surface of the flexible detection structure, the length and layout of the grating wire of the strain gauge on the surface of the flexible detection structure were optimized. Meanwhile at 4 m\u00b7s\u22121 wind speed, the output voltage at varied bridge flexible acquisition systems in the acquisition card was measured. Results indicated coefficient of variation of 3.67%, 1.63% and 1.5%, respectively, which proved the good data acquisition consistency of the system. Through calibration test, the regression equation for the relationship between output voltage and wind speed for three unique sensor signal measuring circuits was established. The determination coefficients R2 for single bridge, half bridge and full bridge circuits were 0.9885, 0.9866 and 0.9959, respectively. In conclusion, by applying the multi-rotor plant protection UAV test platform, the results indicated the maximum relative error of the wind speed at each sampling point of the system at 1.0 m altitude was below 5.61%. Simulated and measured value had an RMSE maximum error of 0.1246 m\u00b7s\u22121. Moreover, downwash airflow detection not only has high accuracy but also has high sensitivity. Thus, there is convenience and practicability in the plant protection offered by this approach. The rapid measurement of UAV wind field and the established two-dimensional wind field model can provide a basis for precise application of agricultural aviation.<\/jats:p>","DOI":"10.3390\/s19112630","type":"journal-article","created":{"date-parts":[[2019,6,10]],"date-time":"2019-06-10T11:39:47Z","timestamp":1560166787000},"page":"2630","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":30,"title":["Design of UAV Downwash Airflow Field Detection System Based on Strain Effect Principle"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2837-2319","authenticated-orcid":false,"given":"Yalei","family":"Wu","sequence":"first","affiliation":[{"name":"College of Engineering, China Agricultural University, No.17 Qing Hua Dong Lu, Haidian District, Beijing 100083, China"}]},{"given":"Lijun","family":"Qi","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, No.17 Qing Hua Dong Lu, Haidian District, Beijing 100083, China"}]},{"given":"Hao","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, No.17 Qing Hua Dong Lu, Haidian District, Beijing 100083, China"}]},{"given":"Elizabeth M.","family":"Musiu","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, No.17 Qing Hua Dong Lu, Haidian District, Beijing 100083, China"},{"name":"Agricultural and Biosystem Engineering Department, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O Box 62000-00200, Kenya"}]},{"given":"Zepeng","family":"Yang","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, No.17 Qing Hua Dong Lu, Haidian District, Beijing 100083, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4825-1875","authenticated-orcid":false,"given":"Pei","family":"Wang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education of PRC, Jiangsu University, Zhenjiang 212300, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,6,10]]},"reference":[{"key":"ref_1","first-page":"18","article-title":"Recent development of unmanned aerial vehicle for plant protection in East Asia","volume":"10","author":"He","year":"2017","journal-title":"Int. J. Agric. Biol. Eng."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.cropro.2016.03.018","article-title":"Droplet deposition and control effect of insecticides sprayed with an unmanned aerial vehicle against plant hoppers","volume":"85","author":"Qin","year":"2016","journal-title":"Crop Prot."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.biosystemseng.2016.02.014","article-title":"Numerical simulation of wake vortices of crop spraying aircraft close to the ground","volume":"145","author":"Zhang","year":"2016","journal-title":"Biosyst. Eng."},{"key":"ref_4","first-page":"15","article-title":"Design of variable spraying system and Influencing factors on droplets deposition of small UAV","volume":"47","author":"Wang","year":"2016","journal-title":"Trans. CSAM"},{"key":"ref_5","first-page":"32","article-title":"Distribution law of rice pollen in the wind field of small UAV","volume":"10","author":"Li","year":"2017","journal-title":"Int. J. Agric. Biol. Eng."},{"key":"ref_6","first-page":"116","article-title":"Influence of UAV rotor downwash airflow on spray width","volume":"49","author":"Yang","year":"2018","journal-title":"Trans. CSAM"},{"key":"ref_7","first-page":"47","article-title":"Droplets movement and deposition of an eight-rotor agricultural UAV in downwash flow field","volume":"10","author":"Tang","year":"2017","journal-title":"Int. J. Agric. Biol. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.cropro.2018.10.019","article-title":"Spray deposition and distribution on the targets and losses to the ground as affected by application volume rate, airflow rate and target position","volume":"116","author":"Musiu","year":"2019","journal-title":"Crop Prot."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.compag.2016.07.022","article-title":"Develop an unmanned aerial vehicle based automatic aerial spraying system","volume":"128","author":"Xue","year":"2016","journal-title":"Comput. Electron. Agric."},{"key":"ref_10","first-page":"1","article-title":"Current status and future trends of precision agricultural aviation technologies","volume":"10","author":"Lan","year":"2017","journal-title":"Int. J. Agric. Biol. Eng."},{"key":"ref_11","unstructured":"Jian, L., Xin, X., Li, Z., Xian, X., Zhu, S., Song, Z., Ping, W., Yan, G., Tao, Z., and Su, D. (2010). Mobile Drone Agricultural Spraying Operation Wind Field Testing Equipment and Testing Method. (CN101718615 A[P]), China Patent."},{"key":"ref_12","first-page":"99","article-title":"Wind Speed Sensor Based on principle of pitot tube","volume":"49","author":"Zhou","year":"2018","journal-title":"Saf. Coal Mines"},{"key":"ref_13","first-page":"99","article-title":"Wireless Hot-film Wind Speed Profiler","volume":"43","author":"Chen","year":"2012","journal-title":"Trans. CSAM"},{"key":"ref_14","first-page":"68","article-title":"Investigation on near-surface wireless wind speed profiler based on thermistors","volume":"48","author":"Liu","year":"2017","journal-title":"Trans. CSAM"},{"key":"ref_15","first-page":"1988","article-title":"Improved design of ultrasonic transducer array for wind measurement","volume":"38","author":"Xing","year":"2017","journal-title":"Chin. J. Sci. Instrum."},{"key":"ref_16","first-page":"89","article-title":"Distribution characteristics of pesticide application droplets deposition of unmanned aerial vehicle based on testing method of spatial quality balance","volume":"32","author":"Wang","year":"2016","journal-title":"Trans. CSAE"},{"key":"ref_17","first-page":"105","article-title":"Design and experiment of a wind speed detection equipment with wind pressure conversion near ground","volume":"39","author":"Huang","year":"2018","journal-title":"J. South China Agric. Univ."},{"key":"ref_18","first-page":"1201","article-title":"The shadow effect compensation for ultrasonic anemometer based on CFD and BP Neural Network","volume":"31","author":"Zhang","year":"2018","journal-title":"Chin. J. Sens. Actuators"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"342","DOI":"10.1016\/0924-4247(94)00918-8","article-title":"Potential for a smart sensor based on an integrated silicon anemometer","volume":"47","author":"Mullins","year":"1995","journal-title":"Sens. Actuators A Phys."},{"key":"ref_20","first-page":"221","article-title":"Development and experiment of a wireless wind speed sensor network measurement system for unmanned helicopter","volume":"45","author":"Hu","year":"2014","journal-title":"Trans. CSAM"},{"key":"ref_21","first-page":"54","article-title":"Wind field measurement for supplementary pollination in hybrid rice breeding using unmanned gasoline engine single-rotor helicopter","volume":"29","author":"Wang","year":"2013","journal-title":"Trans. CSAE"},{"key":"ref_22","first-page":"77","article-title":"Distribution of canopy wind field produced by rotor unmanned aerial vehicle pollination operation","volume":"31","author":"Li","year":"2015","journal-title":"Trans. CSAE"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Wang, P., Yu, W., Ou, M., Gong, C., and Jia, W. (2019). Monitoring of the pesticide droplet deposition with a novel capacitance sensor. Sensors, 19.","DOI":"10.3390\/s19030537"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/j.compag.2012.05.012","article-title":"Computational fluid dynamics applications to improve crop production systems","volume":"93","author":"Bartzanas","year":"2013","journal-title":"Comput. Electron. Agric."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.measurement.2016.01.031","article-title":"Measurement of existing prestressing force in concrete structures through an embedded vibrating beam strain gauge","volume":"83","author":"Biswal","year":"2016","journal-title":"Meas. J. Int. Meas. Confed."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.compag.2008.11.002","article-title":"Modelling airflow within model plant canopies using an integrated approach","volume":"66","author":"Endalew","year":"2009","journal-title":"Comput. Electron. Agric."},{"key":"ref_27","first-page":"112","article-title":"Spatio-temporal distribution of down-wash airflow for multi-rotor plant protection UAV based on porous model","volume":"50","author":"Zhang","year":"2019","journal-title":"Trans. CSAM"},{"key":"ref_28","first-page":"41","article-title":"Numerical simulation and experimental verification on downwash air flow of six-rotor agricultural unmanned aerial vehicle in hover","volume":"10","author":"Yang","year":"2017","journal-title":"Int. J. Agric. Biol. Eng."},{"key":"ref_29","first-page":"35","article-title":"Measuring performance analysis on metal strain plate resisitive senor","volume":"4","author":"Hu","year":"2018","journal-title":"J. Mudanjiang Norm. Univ."},{"key":"ref_30","first-page":"4","article-title":"Design of flexible sensor array based on strain gauge piezoresistive effect","volume":"7","author":"Xiao","year":"2017","journal-title":"Instrum. Tech. Sens."},{"key":"ref_31","first-page":"129","article-title":"Optimization of strain gauge structure parameters based on orthogonal test","volume":"44","author":"Xu","year":"2018","journal-title":"China Meas. Test"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1016\/j.biosystemseng.2004.12.011","article-title":"Remote-sensing technology for vegetation monitoring using an unmanned helicopter","volume":"90","author":"Sugiura","year":"2005","journal-title":"Biosyst. Eng."},{"key":"ref_33","first-page":"64","article-title":"Design and experiment of pesticide droplet deposition detection system based on principle of standing wave ratio","volume":"33","author":"Wu","year":"2017","journal-title":"Trans. CSAE"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/j.compag.2013.02.001","article-title":"Fusion of remotely sensed data from airborne and ground-based sensors to enhance detection of cotton plants","volume":"93","author":"Zhang","year":"2013","journal-title":"Comput. Electron. Agric."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.compag.2018.10.040","article-title":"Spraying strategy optimization with genetic algorithm for autonomous air-assisted sprayer in Chinese heliogreenhouses","volume":"156","author":"Li","year":"2019","journal-title":"Comput. Electron. Agric."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/11\/2630\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:57:18Z","timestamp":1760187438000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/11\/2630"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,6,10]]},"references-count":35,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2019,6]]}},"alternative-id":["s19112630"],"URL":"https:\/\/doi.org\/10.3390\/s19112630","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,6,10]]}}}