| There are many achievements in research on control system of variable rate fertilizer applicator at home and abroad. In spite of good performance, foreign systems cost highly and are based on their own country's conditions such as climate and soil so as to spread in our country inapplicably. While systems developed by domestic researchers have several shortcomings such as machinery complexity, apt to be affected by physical characters of fertilizers and high cost price.In order to overcome these shortcomings of domestic systems, based on the sub- project of "the development of variable rate fertilization control system "which is the technical attack invited public bidding project of national "863" plan, the variable rate fertilizer controller is carried on the research emphatically. By analyzing the primary factor that affect fertilizer and comparing merits and shortcomings of several projects, HMCS (Hydraulic Motor Control System) is selected as controller, which took hydraulic motor as executive outfit. Through controlling rotate speed of hydraulic motor to drive fertilizer sprayer, the purpose of variable rate fertilization can be achieved. When fertilizer sprayer isn't drover by land wheel, the tractor's velocity also affects the quantity of the fertilizer.The design process divides into three parts. the hardware design, the software design and the system test. The hardware is composed of Rate signal gathering part, ARM variable rate controller and executive outfit. Rate signal gathering part, which consists of proximity switch and Radar speed sensor. The signals are transmitted through External interrupt to the CPU, the ARM(Advanced RISC Machine)mainboard includes man-machine interface, memory interface, sensor interface and power source interface, the executive institution comprises several pipeline control parts such as hydraulic motor, driving gear, a tank filled with fertilizers, Spread gear, propeller shaft, Rack, and so on; As to software design, the digital... |
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