Abstract: A coaxial tilt-rotor unmanned aerial vehicle (CTRUAV) and a control method thereof. The CTRUAV includes three rotor modules, five rotors with motors and a control system. The three rotor modules are in an inverted triangle layout. The left and right coaxial tiltable rotor modules in the front of the CTRUAV can rotate around the plane of a fuselage. A rear rotor is installed on the rear fixed-axis rotor module. Two pairs of coaxial rotors are respectively installed on the left and right coaxial tiltable rotor modules. The left and right coaxial tiltable rotor modules include an upper rotor and a lower rotor respectively; the upper rotor and the lower rotor have opposite rotation directions and the same rotation speed during the flight. In the two pairs of coaxial rotors, the rotors on the same layers have opposite rotation directions, and the rotors on different layers have the same rotation directions.

Abstract: The invention relates to a diagnostic method and system for drip irrigation cotton with nitrogen nutrient deficit. First, the sensitive leaf layer of cotton is determined according to the growth stage of cotton, and the spectral reflectance and biomass of each functional leaf in the sensitive leaf layer are collected to calculate average spectral reflectance of the sensitive leaf layer and the maximum leaf biomass. Then, the critical nitrogen concentration was calculated according to the maximum leaf biomass. Finally, the nitrogen nutrition index of cotton is calculated according to the nitrogen concentration and the critical nitrogen concentration. The nitrogen nutrition index is used to characterize the abundance and deficiency of nitrogen nutrition in cotton, so as to determine the abundance and deficiency of nitrogen nutrition in cotton, which can reduce the calculation amount of nitrogen nutrition index, diagnose the abundance and deficiency of nitrogen nutrition in drip irrigation cotton.