遠端監控型簡易三維光電式分級機制之初探與試製

Abstract

In this study a sorting scheme with remote monitoring and operating function for fruits by using photoelectric elements is established. The hardware for this prototype is composed of a photointerrupter, measurement platforms, a data acquisition card, and a personal computer. The friendly human-machine interface software is a LabView program by which dominates the sorting algorithm, data flow and recording, and the parameter setting. The photointerrupter structure consists of a Wheatstone bridge and are lay along with other electronic components. One of the four resistors in the bridge is replaced by a photoresistor as the element of the measurement platforms. There are 48 Wheatstone Bridges were used and are divided into six groups in this study, Only three groups work for each direction scanning. The photoresistors are assembled in matrix on the measurement platform. The measurement platform is equipped with two light sources for vertical and lateral views respectively. The shadows of fruits tested on platform are recognized as their sizes from the photo resistances in photoresistors matrix. The signals equivalent to the photoresistance were captured into the computer by a DAQ interface (PCI-6024E). Then, a LabView program outfitted the sorting algorithm executes the sorting task. The sorting results will be exhibited both on monitor and by voice announcement simultaneously. Far-distance operation is also available on Internet. The on-line system performance shows that there are average long-axis error in 3.94%, average length error in 3.93% and average width-margin error in 3.31% for Fuji apples and average stalk height error in 3.06%, average longitude axis error in 4.13%, average width-margin error in 3.02% for peaches. The overall error will be within 5%. These validate this accomplished system.本研究利用光感測元件搭配電路設計製作可遠端監控型水果分級機制與硬體裝置。硬體部分由檢測電路，光遮斷感知器、量測平台、訊號擷取卡以及個人電腦所組成；軟體部分則包括以LabVIEW完成之操控程式以及分級預估演算法則。光遮斷感知器係由惠斯敦電橋與繼電器等電子元件所構成，其中電橋電路之四個電阻器由一個光敏電阻器與三個電阻器構成，利用電橋二邊電壓差以求出光敏電阻值的大小與變化。 本研究總共使用48組惠斯敦電橋，分成六群，每次僅三群電橋電路工作，其中光敏電阻器以矩陣形式配置的方式安裝在量測平台上。量測平台上方以及側方分別設有光源，依序照射待測水果使其產生陰影，由被水果投影所遮蔽之光敏電阻器電阻值的大小以及行數即可推知分級結果。而由光遮斷感知器送出的訊號，經由PCI-6024E訊號擷取卡進入電腦，配合LabVIEW程式演算與分析光遮斷感知器的訊號，估算水果之大小與分級結果，同步以螢幕顯示與語音方式呈現。整體分級作業亦可透過網際網路，直接由遠端及時監控。系統實驗室內之測試結果顯示，估算富士蘋果大小，平均蒂高誤差為3.94%，平均長度誤差為3.93%，平均寬度誤差為3.31%；而以水蜜桃為試材時，平均蒂高誤差為3.06%，平均長度誤差為4.13%，平均寬度誤差為3.02%。整體誤差均可維持在5%以內，顯示系統之有效及可應用性