Development Of Variable Spraying System For Plant Protection Unmanned Aerial Vehicle

Chemical pesticides plays an irreplaceable role in the aspect of control plant diseases and insect pests effectively,improve the level of agricultural production and solve human food problems,the use of pesticide cannot do without the development of plant protection machinery.Backward plant protection machinery and technology,and improper use of pesticides,will not only reduce the work efficiency,increase the cost of labor,but also inspire crop resistance to diseases and insect pests,reduce the quality of agricultural products,and even cause the waste of pesticide residues,causing environmental pollution,harm to human body.Therefore,in order to reduce the pesticide damage on the human body,save labor,improve work efficiency,this paper completed the research and performance test of Variable spraying system for plant protection unmanned aerial vehicle(UAV),achieved “on-demand spraying".The main research work and innovations are as follows:(1)The paper determined the overall scheme of variable spraying system for UAV(Unmanned Aerial Vehicle)of plant protection in rice blast.The system was consisted of rice disease detection system,hardware and software control section of variable spraying control system for UAV of plant protection and field experiment.The rice disease detection system includes the collection and processing of rice field information and disease diagnosis.Hardware design of variable spraying control system for UAV of plant protection includes five parts,which are design of variable spraying controller,variable actuator and it’s driving circuit,nozzle and determination of its working voltage,remote control module and power distribution system.The software control part comprises initialization module,flow regulating module and wireless remote control module.Field experiments were carried out to analyze the effects of different flight speed and operating height on the distribution of droplet deposition,and determine the best operating height and operating speed.(2)A rice blast detection algorithm was proposed.The video information is collected by the aerial UAV on a predetermined route and the effective frame image is extracted as the rice information image.Rice blast detection and recognition algorithm was designed by the software of Microsoft Visual Studio 2010.Firstly,the multi-scale Retinex algorithm(MSRCR)with color restoration factor C is used to enhance the processing of the obtained valid rice information image,so as to eliminate the influence of different illumination conditions.Then the rice blast area was divided by two values and the ratio of the pixel area to the total area of single image was calculated.According to the ratio results,the grade of rice blast in each image was determined,finally disease rating prescription map was generated.(3)A variable spraying control system for UAV of plant protection was developed.Based on the analysis of variable spraying method of variable spraying control system,variable spraying method of Peristaltic pump flow regulation method is determined,and the calculation of flow rate is explained.The working principle of centrifugal atomizer is studied,and the droplet size and spray pattern under different working voltages are analyzed,then the best operating voltage is determined to be 10 V.And the power system configuration and other hardware configuration were completed.The software control program was programmed based on the hardware configuration of the system.(4)Field Experiment.This paper analyzes the influence of different flight speed and operating height on the distribution of droplet deposition in the variable rate spraying control system of the UAV of plant protection under four different traffic levels.The results of experimental data show that the flying height and flight speed of the UAV of plant protection have significant influence on the droplet density under the control of this system.It also shows that the flying height has a significant effect on the uniform distribution of droplet deposition.And it determines that the optimal operating altitude of the plant protection UAV is 2m,and the optimal operating speed is 1m/s.