採葉機割刀高度控制系統之研究

Abstract

根據農委會的統計，五十歲到六十四歲的農業勞動力人口佔了全農業勞動力人口的44.5%。此數據突顯了農業人力結構的問題。農業人口的高齡化以及農村人口外流使得作物採收期雇工不易。若錯過採收期將使得作物的品項不佳，嚴重者甚至枯黃。在目前還沒有開放農業外勞的政策下，台灣需透過自動化機械改善缺工問題。 本研究的主要目的為研製出一套純電力的割刀高度控制系統，應用於溫網室的葉菜採收。期望控制採收機割刀的位置，使割刀能隨土壤起伏，以達到更低的田間損失率以及使採收過程更順暢。 高度控制系統採用兩個螺桿進行上升以及下降的動作。動力來源使用直流無刷馬達進行螺桿的驅動。控制晶片使用意法半導體之控制晶片(STM32F103ZET6)進行位置演算以及直流無刷馬達的回授控制。運算的資料轉為脈波寬度調變之六步方波，六步方波藉由功率電晶體進行放大後驅動直流無刷電機。 實驗使用假負載模擬割刀之重量。直流無刷馬達使用比例-積分-微分控制對高度進行調整。經數據採集以及負載測試，本系統對高度變化有良好的追隨性能。

According to COA's statistics, agricultural manpower population aged 50 to 64 accounts for 44.5% of the total agricultural manpower population. This data highlights the issue of agricultural manpower structure. For example, an aging agricultural population and labor force migration have made the timely harvesting of crops more challenging. Farmers who miss the optimum harvest time will often harvest crops of poorer quality. Furthermore, under the current government policy, the agricultural labor force is not legally approved. Moreover, problems related to a worker shortage in Taiwan could be improved by increased adoption of automated machinery. The primary objective of this study was to develop a set of pure electric cutter-height control systems which could be used to harvest leafy vegetables in greenhouses. Field machinery that is equipped with proposed system can sense soil heights and respond by adjusting the cutter-height. This should lower field loss rates and facilitate a smoother harvesting process. The height control system uses two screws to ascend and descend and employs a brushless DC motor with PID control as a power source to move the screws. Height calculations and brushless DC motor feedback control are made using the Microcontroller STMicroelectronics STM32F103ZET6. Calculated data are converted into a six-step square wave of pulse width modulation (PWM), which is amplified by a power transistor to drive the DC brushless motor. In this study, we used a fictitious load to simulate the weight of the cutter. After completing data collection and load tests, we confirmed that the proposed system responds well to soil height changes.