Study On The Control System Of Rice Leaf Fertilizer Spraying By UAV

The precise application of foliar fertilizer plays a crucial role in the growth and development of rice in various periods.UAV operation has the characteristics of high work efficiency,low production cost and resource saving,and it has been widely used in rice foliar fertilizer spraying operation.The problems of low precision and system instability of the UAV leaf fertilizer spraying flow control system are presented.The main research work is conducted as follows:(1)According to the flight parameter setting and agronomic requirements of rice foliar fertilizer spraying operation,the main components meeting the research requirements were selected,the hardware circuit of spraying control system was designed,the spraying platform of rice foliar fertilizer was built,and the hardware foundation of spraying test was established.(2)The mathematical model of electromagnetic flow regulating valve is established,the fuzzy PID controller is designed,and the simulation model is established in Matlab software for the step signal of the system input under different parameters and the sinusoidal signal at different frequencies.The simulation results show that when the proportional coefficient is 1,the integral coefficient is 0.1 and the differential coefficient is 0.5,the proportional coefficient is0.08,the integral coefficient is corrected to 0.0005,and the differential coefficient is 0.002,the fuzzy PID control effect is the best,the time when the system step response reaches the steady state is 0.526 s;as the sinusoidal signal increases,the system steady state error increases,and the following accuracy of the response curve and the target curve decreases.(3)The simulation model was built in Matlab / Simulink and the programming of sliding mode control and fuzzy sliding mode control were written in Keil 5 environment.Simulation and analysis of the dynamic response of the system under different input signals,The simulation results show that the minimum time for the step response to reach steady state is 0.142 s,The minimum time for the fuzzy sliding mode controlling the step response to reach a steady state is0.095 s,Note that with the increasing parameters of the scale switching function,Fuzzy sliding mode control step response has a shorter adjustment time than the sliding mode control system,With a smaller steady-state error,Shorter rise time;Compared with the input of 0.5 Hz and 1 Hz sinusoidal signals respectively:the fuzzy sliding mode control response curve is more consistent with the target amount,which is more fit to the target curve,the system error is smaller,and there is no delay phenomenon;Compared with the control performance of fuzzy sliding mode and sliding mode and fuzzy PID,the performance indexes of fuzzy sliding mode algorithm are better than fuzzy PID and sliding mode algorithm.(4)The spray flow accuracy test shows that the maximum average flow error of the actual spray flow and the theoretical spray flow is 2.26%,which is less than 3.34% of the fuzzy PID control and 9.12% under the sliding mode control.The spray deposition test shows that the system has a good effective amplitude at different flight speeds,and the spray coefficient of variation at each sampling position is less than 10%,and the closer to the central sampling point,the system has strong stability and robustness.