| Foliar fertilizer can improve drought resistance and soil environment of soybean,increase soybean yield and improve product shape.Currently.Soybean is one of the crops with a wider planting area and is the main crop in rural areas.Due to long-term irrational farming,the deterioration of rural ecological environment,unbalance of soil p H and destruction of water resources make it difficult to obtain adequate nutrients in the growing process of soybean,affecting the yield and quality of soybean.In view of these phenomena,a real-time variable control system of soybean leaf fertilizer,which is different from the prescription chart technology,is studied in this paper.The spraying amount of the spray system can be adjusted in real time according to the soybean growth,so as to improve the spraying accuracy and reduce the waste of fertilizer.In this paper,the mathematical model of soybean variable spraying control system is established,simulation analysis is carried out with Matlab,and indoor and outdoor tests are carried out to analyze and optimize the parameters of variable control system and improve the spraying accuracy.Specific research contents and conclusions are as follows:(1)Analyze the research objectives and requirements of the variable spraying control system,and study the hardware equipment and software programming of the variable spraying control system combined with the actual working conditions and the requirements of soybean leaf fertilizer spraying.The spray characteristics of the variable spray control system were studied,and the pressure regulation range of the spray control system was determined to be 0.2-0.4MPa,and the flow range was 0.95—1.83L/min.(2)The mathematical model of variable control system of soybean leaf flour fertilizer was established,the transfer function of pressure regulating proportional valve was deduced,and the dynamic characteristics of the system were analyzed.Variable spraying control system adopts incremental PID control algorithm,and simulink toolbox in Matlab is used to build the control system model and carry out simulation analysis to determine the feasibility of variable spraying control system.(3)The variable spraying control system test platform was built and the indoor bench test was carried out.It was determined that the pressure and flow detection errors of the variable spraying control system were 2.5% and 2.04%,respectively,which were within the controllable range and met the design requirements.It is verified that the transient response time of the variable spraying control system is between 0.7—1.2S,and the response time is less than 1.5S to meet the test requirements.Outdoor multi-factor tests were conducted,and the results showed that the influence degree of each factor on spray distribution was in the following order:sprinkler spacing > sprinkler height > sprinkler pressure.Design-Espert8.0.6 software was used to analyze and optimize the data.The results showed that when the spacing of sprinkler heads was 500 mm,the height of sprinkler heads was 400 mm,the pressure of sprinkler heads was0.3MPa,and the variation coefficient of spray distribution was 2.23%,each index was the optimal parameter. |
