本論文描述自動遮蔽金屬電弧焊接控制系統的發展，它可以取代需要良好訓練的技工手動焊接操作。雖然機器人焊接在許多的焊接應用上已經取代了人工焊接，但是在發展自動化焊接系統過程中，由於其複雜的系統過程而無法完全開發。目前，有幾種控制方法被應用到這個焊接系統控制上。首先，我們推導此焊接控制系統的數學模型，它主要由一交流伺服馬達驅動之焊條進給控制機構所組成，此自動化銲接系統可以視為一個焊條進給速度控制系統。當此一系統被當成焊條進給速度控制機構時，我們可以把它當成一階或二階動態系統，＂Matlab IDENTIFICATION Toolbox ＂被用來估測此一階或二階動態系統的最佳合適之參數值。接下來，我們設計一個以基因演算法為主軸，作為參數鑑別之PID控制器。在模擬與實驗中，當系統加入外部干擾之後，我們的焊接系統就會因為外部干擾的不確定性加入，而無法產生起弧也造成焊接失敗的情形。在外部干擾補償之控制策略，我們利用基因演算法去辨別外部干擾之振幅或頻率。在模擬與實驗中，經外部干擾補償後，焊接系統也可以順利的起弧及保持焊條進給的穩定性。此後，適應性模態控制器是由等效控制部分與迫進控制部分所組成。從李亞普諾夫函數(Lyapunov function)所推導的適應性法則及設計一個改良型之飽和函數，可以用來得到近似順滑模態控制(Sliding mode control)的等效控制部分。因此，系統可以強迫收斂到零點狀態。因此，可以保證適應性順滑模態控制器的穩定性和用來調節電焊進給機構，以控制SMAW銲接系統的電弧電流大小。在模擬與實驗焊接的結果中，以適應性順滑模態為基礎的控制器，可以使焊接過程更為有效率。This thesis describes an automatic welding control system developed for alternating current shield metal arc welding (SMAW). It can replace manual operations which require a well-trained technician. Robotic welders have replaced manual human operations in many welding applications, but the automated process control systems have not been fully developed due to the complexity of the process. In current, several methods are applied to control this SMAW system.First, we derive a mathematical model of the welding control system, which consists primarily of an electrode feed-rate mechanism driven by an AC servomotor. Both first-order and second-order dynamics are used to represent this mechanism, when we consider it for an electrode feed-rate velocity control system. The “Matlab IDENTIFICATION Tool Box” is used to estimate the best-fit values of the parameters of the welding control system, using first-order and second-order dynamics, respectively.A GA-based PID and adaptive siding mode arc current controllers can be used to modulate the rate of the first-order electrode feed-rate mechanism that regulates the arc current. The electrode feed-rate mechanism for this controller is driven by an AC servomotor which can both compensate for the molted part of the electrode and for the undesirable fluctuations of the arc length during welding operation. It can also be easily applied to any welding system where the electrode is consumed during the welding process. Furthermore, we use GA to cancel and compensate the external force on the SMAW system, not only can effective to accomplish experimental demand, but also can maintain the stability of welding process for the SMAW system. The feasibility and the simplicity of this controller for an SMAW system are verified by a simulation. The experimental results verify the feasibility of the proposed controller and also show that it can effectively perform arc welding, as well as effectively initiate the welding arc.
