| The level of agricultural development plays an important role in national economy.As a kind of economic crop in China,flue-cured tobacco needs to apply chemical fertilizer to increase the yield of flue-cured tobacco in the same process as many crops.At present,the commonly used chemical fertilizer in China is solid fertilizer,but the effective utilization rate of solid fertilizer is low.The liquid fertilizer can replace the traditional solid fertilizer,which can improve fertilizer efficiency and reduce environmental pollution.The development of liquid fertilizer has promoted the development of liquid fertilizer application machinery.At present,most of the liquid fertilizer applicators on the market are used in ordinary plain areas.and there are few fertilizing machines for flue-cured tobacco in mountainous areas.Therefore,it is of practical significance to carry out research on precise fertilization system of flue-cured tobacco in mountainous terrain.The main research contents of this paper are as follows:(1)Research on the scheme of precise fertilization system for liquid fertilizer.The overall design principle was determined for the fertilization demand of flue-cured tobacco crops in mountain areas,and the whole machine plan of the system was studied.(2)Design and analysis of key components of the fertilization system.Firstly,the loop scheme of the fertilizer supply device was compared and analyzed,and the main road throttle regulation loop was determined,and then the structure was designed.The diameter of the pipeline of the fertilizer pipeline was determined by calculation;the support device of the Tanaka was designed and the hose guide beam was optimized and the size parameters were determined.Finally,the fertilization gun structure design and related component selection were carried out to establish a fertilization gun control model.(3)Research and analysis of fluid characteristics of fertilization channels.Calculating the lift loss and pipeline pressure loss of the calibration system to ensure that the fertilizer fluid could be successfully transported to the fertilization gun inlet;Fluent simulation analysis of the fertilization gun fluid domain,numerically verify that the fertilization gun was designed to meet the export fertilizer demand.(4)Hardware design of precise control system for fertilizing guns.The Altium Designer software tool was used to design the minimum system module,key input module,LCD display module,electric control valve drive module and flow alarm circuit module of the single-chip microcomputer to determine the hardware circuit schematic of the precise fertilization control system.(5)The software of precision control system was designed and implemented,using PID control method and adaptive fuzzy PID control method,taking step signal as input,establishing two control models in MATLAB and simulating could get regular PID control response time is 0.35 s,and the response time of adaptive fuzzy PID control is 0.15 s.Comparison shows that the adaptive fuzzy PID control method is superior.According to this method,the software program of the system is programmed in Keil uVision.(6)Trial production of fertilization gun prototype and precise control test of fertilization gun.It could be concluded that the control error of fertilization rate in fertilization gun fertilization range is 4.7%,the lowest is only 1%,which is lower than the error of 8% required by tobacco industry,and could be verified the hardware and software feasibility of the precision fertilization control system. |
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