Next Article in Journal
The AMERIGO Lander and the Automatic Benthic Chamber (CBA): Two New Instruments to Measure Benthic Fluxes of Dissolved Chemical Species
Previous Article in Journal
Monitoring Methods of Human Body Joints: State-of-the-Art and Research Challenges
Open AccessArticle

Design of UAV Downwash Airflow Field Detection System Based on Strain Effect Principle

1
College of Engineering, China Agricultural University, No.17 Qing Hua Dong Lu, Haidian District, Beijing 100083, China
2
Agricultural and Biosystem Engineering Department, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O Box 62000-00200, Kenya
3
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education of PRC, Jiangsu University, Zhenjiang 212300, China
*
Author to whom correspondence should be addressed.
Sensors 2019, 19(11), 2630; https://doi.org/10.3390/s19112630
Received: 30 April 2019 / Revised: 5 June 2019 / Accepted: 6 June 2019 / Published: 10 June 2019
(This article belongs to the Section Physical Sensors)
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·s−1 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·s−1. 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. View Full-Text
Keywords: strain effect principle; flexible polypropylene detection structure; ANSYS simulation; one-way fluid-solid coupling; downwash airflow wind field measurement strain effect principle; flexible polypropylene detection structure; ANSYS simulation; one-way fluid-solid coupling; downwash airflow wind field measurement
Show Figures

Figure 1

MDPI and ACS Style

Wu, Y.; Qi, L.; Zhang, H.; Musiu, E.M.; Yang, Z.; Wang, P. Design of UAV Downwash Airflow Field Detection System Based on Strain Effect Principle. Sensors 2019, 19, 2630.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop