PI+Feed Forward Controller Tuning Based on Genetic Algorithm for Liquid Level Control of Coupled-Tank System

Öz

One of the main problems in the control of the coupled tank liquid level systems, which are used frequently in water treatment systems and petrochemical industry today, is to determine the water flow rate between the two tanks. In this paper, proportional-integral +feed forward control method (PI+FF), whose parameters are determined using genetic algorithm (GA), one of the heuristic optimization methods, is used to solve this problem. In addition, in order to show the performance of the GA-based controller, the PI+FF controller that PI parameters obtained using the Ziegler-Nichols (Z-N) method are applied to the same system and the real-time application results of both controllers are compared. The experimental results showed that the controller, which parameters are determined by GA, reached the desired reference value with less settling time and less overshooting when it compared to the Z-N method based controller, and also it has given faster response to sudden changes in the system.

Anahtar Kelimeler

• Liquid level systems
• Ziegler-Nichols method
• Genetic Algorithm
• PI controller

İkili Tank Sisteminin Sıvı Seviye Kontrolü için Genetik Algoritma Tabanlı PI+İleri Besleme Kontrolcü

Öz

Günümüzde su arıtma sistemlerinde ve petrokimya endüstrisinde sıklıkla kullanılan ikili tank sıvı seviye sistemlerinin kontrolündeki en temel problemlerden biri iki tank arasındaki sıvı akış oranının belirlenmesidir. Bu çalışmada bu problemi gidermek amacıyla oransal-integral (PI) + ileri besleme (FF) kontrolcünün (PI+FF) parametreleri sezgisel optimizasyon yöntemlerinden genetik algoritma (GA) kullanılarak belirlenmiş ve ikili tank sistemine uygulanmıştır. Ayrıca GA tabanlı kontrolcünün performansını göstermek amacıyla Ziegler-Nichols (Z-N) yöntemi kullanılarak parametreleri elde edilen PI+FF kontrol yöntemi aynı sisteme uygulanmış ve her iki kontrolcünün gerçek zamanlı uygulama sonuçları karşılaştırılmıştır. Deneysel sonuçlar, parametreleri GA ile belirlen kontrolcünün Z-N yöntemi kullanılarak elde edilen kontrolcüye oranla istenilen referans değere daha küçük yerleşme zamanı ve daha az yüzde aşım ile ulaştığı ve ayrıca sistemde meydana gelen ani değişimlere daha hızlı tepki verdiği gözlemlenmiştir.

Anahtar Kelimeler

• Sıvı seviye sistemleri
• Ziegler-Nichols yöntemi
• Genetik Algoritma
• PI kontrolör

Kaynakça

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