Objective  Flight quality of plant protection UAV is an important factor affecting the effectiveness of aerial spraying. The objective of this research is to explore flight qualities and operation effects of plant protection UAVs of different types and control models, which can provide data support and guidance for selecting the models and improving the spraying technologies.

Method  Flight paths and parameters of single-rotor oil-powered plant protection UAV(Se-UAV), single-rotor electric plant protection UAV(Se-UAV), semi-automatic-quad-rotor electric plant protection UAV(Saqe-UAV) and full-automatic-quad-rotor electric plant protection UAV(Faqe-UAV) were obtained by micro-light Beidou navigation satellite system, and flight qualities (including path accuracy, variation uniformity of flight parameter and path length) were analyzed and evaluated.

Result  Flight qualities of quad-rotor plant protection UAVs were better than those of single-rotor plant protection UAVs, and flight quality of Faqe-UAVwas better than that of Saqe-UAV. Faqe-UAV had the best uniformity of flight parameters throughout the operating area, and the uniformities of flight speed and flight height were 3.66% and 4.67%, respectively. The average route deviation of Faqe-UAV was the minimum, which was 0.172 m. In addition, the effects of flight direction on flight parameters of plant protection UAVs under full-autonomous and semi-autonomous control modes were insignificant and significant respectively. The effect of route length on flight parameters of plant protection UAV under semi-autonomous control mode was not significant, but route length had a significant effect on flight speed of plant protection UAV under full-autonomous control mode.

Conclusion  In the aerial spraying process, quad-rotor plant protection UAV under full-autonomous control mode has the best flight quality, and gives spraying quality more security.