Study On Structure And Hydraulic Step-less Speed Control Of The Variable Rate Fertilizer Applicator

Precision agriculture is a new trend of modern agriculture development all over the world, which is quantitative timing to modernize farming operation technology and management according to the spatial variation based on information technology and intelligent agricultural system is its core system. To overcome these shortcomings, such as Poor real-time, uniformity of low, fertilizer damp easily blocked and large transmission delay, the Mechanical transmission system, equipment structure and control system of agricultural system were analyzed and improved designed.(1) Aiming at these shortcomings of single variable fertilizing application, such as Small adjustably range, volatile in low speed and less uniformity, design meth based on manual adjustment was provided, the bi-variable fertilizing application was designed, which can be adjust the fertilizer feeder speed and fertilizer feeder opening at the same time. In order to automatically control the ratio of fertilizer application, three-feedbox was designed in the bi-variable fertilizing application.(2) In order to enhance the high transmission accuracy of hydraulic system achieves precise fertilizing. With particular emphasis on the stability of the hydraulic circuit and the actuation control method, mathematical model and simulation model for hydraulic sleepless speed system were established. More specifically, hydraulic sleepless speed system with stab oil circuit and oil pressure sensor was designed to ensure hydraulic system stability, while PID control algorithm was employed to compensate transmission error according to the mathematical model and hydraulic sleepless speed system was simulated in different PID control parameters.(3) The five-factor model control system with industrial PC as upper computer and PLC as lower computer was designed, which is fertilizer consumption of N, P, K and fertilizer feeder speed and fertilizer feeder opening. The digital signal form the data acquisition system were received by the upper computer PC and the upper computer have formulas for these present fertilization ratio parameters. The lower computer receives the fertilization ratio parameters to control hydraulic motor velocity achieves precise fertilizing.(4) Digital PID and fuzzy PID control experiment were done, through which can validate respective control capability of the Digital PID and fuzzy PID control model. Through analysis and comparison the last test data, some conclusions are obtained. The first conclusion is system stability of fuzzy PID control model more than the Digital PID model, the last is the control model received the anticipative effect.(5) Delay test method was designed based on error amplifier delay time at most method, the experimental results of delay time is0.852s and its result is satisfying. Through commissioning tests to know the coordination and homogeneity parameters of the bi-variable fertilizing application soft and hardware system structure. Through analysis and comparison the last test data, some conclusions are obtained, the fist is the relative homogeneity when the tractor speed keep the in10km/h, the fertilizer quantity undulate greatly when the tractor speed low the5km/h, the last collusion is the results are reasonable and applicable.