1、4150 英文单词，英文单词，2.1 万英文字符万英文字符，中文中文 6300 字字 文献出处：文献出处：Kamgar S, Noei-Khodabadi F, Shafaei S M. Design, development and field assessment of a controlled seed metering unit to be used in grain drills for direct seeding of wheatJ. Information Processing in Agriculture, 2015, 2(3-4): 169-176 Design, deve
2、lopment and field assessment of a controlled seed metering unit to be used in grain drills for direct seeding of wheat S. Kamgar, F. Noei-Khodabadi, S.M. Shafaei Abstract A new controlled seed metering unit was designed and mounted on a common grain drill for direct seeding of wheat (DSW). It compri
3、sed the following main parts: (a) a variable-rate con- trolled direct current motor (DCM) as seed metering shaft driver, (b) two digital encoders for sensing the rotational speed of supplemental ground wheel (SGW) and seed metering shaft and (c) a control box to handle and process the data of the un
4、it. According to the considered closed-loop control system, the designed control box regularly checked the revolution per minute (RPM) of seed metering shaft, as operation feedback, using its digital encoder output. The seeding ratewas determined based on the calculated error signal and output signal of the digital encoder of the SGW. A field with four different levels of wheat stubble coverage (10%, 30%, 40% and 50%) was selected for evaluation of the fabricated seed metering unit (FSMU). Th
