泡茶機自動控制裝置之研發

Abstract

有鑒於國內泡茶文化，並參考歐美咖啡機結構，本研究致力設計適合沖泡台灣特色茶種的自動化機械器具。其主軸在於設計泡茶機之控制器，並搭配簡易的元件來進行研發與測試。應用單晶片微處理器當整個系統之控制核心，使用電壓型溫度感測器做為溫度感測，利用微處理器之數位類比轉換器將溫度轉換成電壓值輸出。以齊格勒－尼古斯（Ziegler-Nichols）法則找出比例積分微分控制（PID Control）中重要的三個參數：Kp、Ki、Kd，並將其代入溫度誤差演算法中。控制主程式設計六種不同溫度升溫模式以配合六種不同特色茶種：綠茶、龍井茶、文山包種茶、鐵觀音茶、白毫烏龍茶與紅茶之應用。在操作介面上使用兩位數七段顯示器來顯示即時溫度，搭配液晶顯示模組和功能按鍵可讓使用者作沖泡選擇。經過升溫及降溫測試，可證明系統電路正確性及控制流程的穩定性，實驗結果顯示本研究所設計之自動泡茶機，不論是升溫或降溫，其誤差皆可精確控制恆溫在±2℃之內。

Based on the tea making culture in Taiwan and the components of coffee machines, it is tried to develop an automatic device suitable for characteristic tea. This study used some simple components to design the tea maker controllers and focused on the development and testing of controllers. A single chip microprocessor has been applied to the key part of control system along with a voltage type temperature sensor measuring temperature. Then, the Celsius degree data are obtained from output voltage by analog to digital converter of microprocessor. Three important parameters were derived: Kp, Ki, and Kd in PID control by using Ziegler-Nichols rule which are substitution for error mathematical function. 6 heating modes were designed to fit 6 characteristic teas（Green tea, Long Jing Tea, Wun Shan Paochong tea, Tieh Kuan Yin tea, White-tip Oolong tea, Black tea）in main control program. This system shows the immediate temperature by seven-segment display. Liquid Crystal Display and buttons are provided for heating modes. It has been proven that the circuit of this system is precise and control process is stable. Experimental results have shown that the precision of constant temperature is within ±2℃ no matter heating or cooling.