喜樹枝葉採收機構之基礎研究

Abstract

喜樹之嫩葉富含喜樹鹼，此為抗癌藥物的原料之一，所以對其需求量會愈來愈多，然而現今種植樹的農民並沒有一台合適的收割機械能大量且快速的採收其葉片，本研究目的為參考現今的採收機械構造，設計出合適採收喜樹枝葉之切割機構並利用繪圖軟體設計喜樹枝葉採收機之雛型。 經過調查現今農業上最常使用之切割機構，本文決定以往復切割機構做為主要測試切割機構，同時利用市面最常見的聯合收穫機用割刀組和採茶機用切割機構來進行測試；前者刀具為水平型式，刀片為鋸斷狀，後者之刀具為一弧型式，刀片為光滑狀。 為了準確地了解實際切割情形，本實驗於室內利用整組切割機構來切割多束喜樹，一開始以二種不同的台車前進速度(0.52 m/s和0.63 m/s)和二種割刀速度(聯合收穫機割刀轉速為230 rpm和330rpm，採茶機收穫機割刀轉速為750 rpm和850 rpm)進行測試，實驗中紀錄切割時扭力的變化及切割後之撕裂率以判斷切割性能之好壞。 切割實驗結果以聯合收穫機切割機構在二種割刀轉速和台車速度下之切割撕裂率在5%以下，優於採茶機切割機構只有在台車速度0.52 m/s下切割撕裂率在5%以下；接著增加二組聯合收穫機割刀轉速200 rpm和420 rpm和一台車速度0.84 m/s加以測試，總合切割結果發現聯合收穫機割刀轉速330 rpm和420 rpm在三種台車速度下皆有好的切割性，而割刀轉速200 rpm和230 rpm只有在台車速度1~2 km/hr下有好的切割性。 切割扭力實驗結果顯示，聯合收穫機最大切割空轉扭力和割刀迴轉速有線性關係；而切割扭力與切割動力和切割速度比(k值)有指數函數關係，切割所需扭力與動力隨k值增加而增加。 最後本研究認為聯合收穫機用割刀機構比採茶機用割刀機構合適於喜樹枝葉採收上。

The highest level of camptothecin is found in the leaves of camptotheca (happy tree). This is a potent anti-cancer material, and in trying to harvest the leaves, farmers have so far lacked a suitable machine to pluck happy tree’s baby leaves effectively. The purpose of this study was to find the best device for plucking leaves from happy trees, and then use software to design a prototype of the leaf-plucking machine. In this study, the reciprocating knife mechanism was chosen. Two types of reciprocating cutting devices were used. One is a reciprocating cutterbar from a rice combine. It has a horizontal pattern and a serrated blade. The other is a cutterbar from a tea plucking machine that has an arc pattern and a smooth blade. In order for the cutting simulation to be realistic, this experiment tested the whole cutting mechanism at two different forward speeds (0.52 m/s and 0.63 m/s) and various knife velocities (0.38 m/s and 0.55 m/s for the reciprocating cutterbar from a rice combine, 0.88 m/s and 0.99 m/s for the cutterbar from a tea plucking machine) and recorded the torque and ratio of broken branches to determine which one is the best cutting mechanism. The result showed the ratio of broken branches for the reciprocating cutterbar from a rice combine at two different forward speeds and knife velocities is less than 5%. At 0.52 m/s forward speed for the reciprocating cutterbar, the ratio of broken branches for the tea plucking machine was less than 5%. Two additional knife velocities (0.33 m/s and 0.70 m/s) and one additional forward speed (0.84 m/s) for the reciprocating cutterbar from a rice combine were tested. The results showed that the knife velocities of the reciprocating cutterbar from a rice combine at 0.55 m/s and 0.70 m/s on the three above mentioned forward speeds had an excellent cutting property. But the knife velocities of the reciprocating cutterbar from a rice combine at 0.33 m/s and 0.38 m/s only on the forward speeds 0.52 m/s had an excellent cutting property. Another result showed that the max net torque requirement of the reciprocating cutterbar from a rice combine during the cutting operation had a linear relation with the knife velocities. Torque and power requirements during the cutting operation had an exponential relation with the ratio of velocity. If the velocity ratio increased, the torque and power requirement also increased. The conclusion from this study is that the reciprocating cutterbar from a rice combine is better for plucking happy trees’s leaves.