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題 名 | GPS速度控制器應用於變率施噴系統之基礎研究=Basic Study of a GPS-guided Speed Controller Used in the Variable-Rate Spraying System |
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作 者 | 洪景祥; 葉仲基; | 書刊名 | 中華農學會報 |
卷 期 | 7:6 民95.12 |
頁 次 | 頁595-613 |
分類號 | 434.251 |
關鍵詞 | 精準農業; 變率施噴; 全球定位系統; Precision agriculture; Variable-rate spraying; Global positioning system; GPS; |
語 文 | 中文(Chinese) |
中文摘要 | 本文係在精準農業考量的前是下,嘗試設計一新型變率施噴系統,使施噴作業不會因為人為操作行進速度的差異而產生施噴不穩定的情況,以達到更精準的撒佈效果。研究中選用與噴藥車上相同機型的噴藥機,利用全球定位系統內建的速度模揓功能,模擬噴藥車行進時的速度,透過自行研製的GPS速度控制器將信號傳送至一電動比例閥,藉由電壓信號值來控制電動比例閥的開度,以達到變量施噴的目標。 因此,本研究乃結合了噴藥作業系統、全球定位系統以及電子導航系統,整個實驗共分為三個階段:第一階段進行GPS全球定位系統實測及比例閥流量實測作業,第二階段進行比例閥與GPS速度控制器連結的實測作業,而第三階段則是進行GPS速度控制器連結比例閥之流量實測作業。實驗結果顯示,當GPS衛星設定系統的PDOP值小於4.9時,其最大偏移量小於2.2公尺,該定位精度大致已符合精準農業的要求。另外,實驗中亦加裝了自行設計的穩流器,改變GPS速度控制器的電壓源值,能夠解決比例閥無法定位重的視的問題,可以使比例閥作動更能達到變率施噴的需求。最後,經由改變幫浦出水壓力(九種設定),以及利用速度(8km/h與速度15km/h)改變比例閥開度的方式,共可獲得18種變率施噴的結果。 |
英文摘要 | In this study a speed controller is developed for the variable-rate spraying system in precision agriculture. This controller is combined with the variable-rate spraying system of a self-propelled boom sprayer. The spraying flow rate can adjusted and is dependent on the vehicle travel speed with the help of GPS (Global Positioning System). The travel speed of boom sprayer can be simulated in the laboratory, by means of the function for speed simulation in a GPS receiver (GARMIN 12XL). The signals of GPS receiver will be transmitted to the speed controller. Through the preset values of a memory card in this controller, the different electric voltages will be produced according to the corresponding speed levels. The openings of the proportional flow control valve will be changed dependent on these different voltages. The spraying flow rate will then be matched with the travel speed of the vehicle, and as a result variable-rate spraying can be achieved more precisely. The experiment is divided into three steps. At first, the function of GPS system and the proportional flow control valve control system were tested separately. Then, the control valve and GPS-guided speed controller were combined together, and the communication between them was tested. Finally, the actual flow measurement, under the control of the GPS-guided speed controller, was tested. The flow rate Qa was read using a flow meter and the flow rate Qb was measured using a measuring cup & a stop watch respectively. The relationships between the flow rates and the travel speeds by different pump pressures are concluded as flows: When the pump pressure is fg/c□, the tendency equations are: Qa: Y=-0.0307□+1.4917X-0.3669 □=0.9835 (X: travel speed; Y: flow rate Qa) Qb: Y=-0.0315□+1.488X-0.3394 □=0.9825 (X: travel speed; Y: flow rate Qa) When the pump pressure is 10 kgf/c□, the tendency equations are: Qa: Y=-0.0403□+1.9528X-0.53 □=0.9798 (X: travel speed; Y: flow rate Qa) Qb: Y=-0.0315□+1.488X-0.3394 □=0.9825 (X: travel speed; Y: flow rate Qa) When the pump pressure is 15 kgf/c□, the tendency equations are: Qa: Y=-0.0486□+2.2445X-0.4923 □=0.9842 (X: travel speed; Y: flow rate Qa) Qb: Y=-0.0315□+1.488X-0.3394 □=0.9825 (X: travel speed; Y: flow rate Qa) From the above equations it is obvious that travel speed and flow rate are highly correlated. The experiment showed that several variable-rate spraying outputs can be obtained through the different openings of the proportional flow control valve, corresponding to the travel speeds of vehicle and various pressure settings of the pump. By introducing this newly developed GPS-guided speed controller to a self-propelled boom sprayer the performance of the variable-rate spraying system will improve significantly. |
本系統中英文摘要資訊取自各篇刊載內容。