Sliding Mode Controller Design and Comparison with Feed Forward +PI Controller for Fluid Level System Control of Couple Tank

Year 2022, , 901 - 917, 31.12.2022

Sadrettin Gölcügezli , Ahmet Dumlu

https://doi.org/10.35193/bseufbd.1100155

Abstract

In this article, sliding mode control (SMC) is applied to the Couple-Tank system, which is the typical application of the fluid level tank system used in industrial facilities and its control is examined. The mathematical model of the nonlinear Couple-Tank system was found out for both tank systems. The system was designed by combining  the dynamic equations of the Couple-Tank system with the sliding mode control. The important aspect of SMC is to control a nonlinear dynamic system that is exposure to external disturbances or uncertainties using a switching function that ensures that the system states remain on the slip surface. The sliding mode control (SMC) was chosen by the author because of its robustness against parameter changes and distortions. In this article, the second order SMC technique is used to avoid the unwanted chattering effect. The control signal for the sliding mode control was calculated as the sum of the switching control signal and the equivalent control signal. The transfer function of the nonlinear Couple-Tank system was calculated by the Taylor series linearization method. In this article, the Tank 2 transfer function was determined by the ratio of the input voltage of the system to the fluid level. The sliding mode control applied to the Couple-Tank system and the feed forward PI controller (FF-PI), which is another type of control, are compared. The monitoring of the measured fluid level to the reference fluid level and error detection between the measured liquid level and the desired fluid level were examined in the simulation environment of the Couple-Tank system designed by applying the sliding mode control (SMC). It has been observed that the system designed with sliding mode control (SMC) can follow the desired fluid level quite successfully.

Keywords

Sliding Mode Control, Feedforward PI, Fluid Level Systems, Nonlinear Control

İkili Tank Akışkan Seviye Sisteminin Kontrolü İçin Kayan Kipli Kontrolcü Tasarımı ve İleri Besleme + PI Kontrolcü Karşılaştırılması

Abstract

Bu makalede endüstri tesislerinde kullanılan akışkan seviye tank sisteminin tipik uygulaması olan İkili-Tank sistemine kayan kipli kontrol (SMC) uygulanarak kontrolü incelenmiştir. Doğrusal olmayan İkili-Tank sisteminin matematiksel modeli her iki tank sistemi için çıkarılmıştır. İkili-Tank sisteminin dinamik Denklemleri, kayan kipli kontrol ile birleştirilerek sistem tasarlanmıştır. SMC'nin önemli yönü, sistem durumlarının kayma yüzeyinde kalmasını sağlayan bir anahtarlama işlevi kullanarak dış bozuculara veya belirsizliklere maruz kalan doğrusal olmayan bir dinamik sistemi kontrol etmektir. Yazar tarafından kayan kipli kontrol (SMC), parametre değişimlerine ve bozulmalara karşı sağlamlığı nedeniyle tercih edilmiştir. Bu makalede istenmeyen çatırdama etkisinden kaçınmak için ikinci dereceden SMC tekniği kullanılmıştır. Kayan kipli kontrol için kontrol işareti, anahtarlama kontrol işareti ile eşdeğer kontrol işaretinin toplamı olacak şekilde hesaplanmıştır. Doğrusal olmayan İkili-Tank sisteminin transfer fonksiyonu, Taylor serisi doğrusallaştırma yöntemiyle hesaplanmıştır. Bu makalede Tank 2 transfer fonksiyonu, sistemin giriş geriliminin akışkan seviyesine oranıyla belirlenmiştir. Transfer fonksiyonu için İkili-Tank sistemine uygulanan kayan kipli kontrol ile başka bir kontrol şekli olan ileri beslemeli PI denetleyicisi (FF-PI) karşılaştırılmıştır. Kayan kipli kontrol (SMC) uygulanarak tasarlanan İkili-Tank sisteminin MATLAB-Simulink simülasyon ortamında ölçülen akışkan seviyenin, referans akışkan seviyesine takibi ve ölçülen akışkan seviyesi ile istenilen akışkan seviyesi arasındaki hata tespiti incelenmiştir. Kayan kipli kontrol (SMC) ile tasarlanan sistem oldukça başarılı bir şekilde istenilen akışkan seviyesini takip edebildiği gözlemlenmiştir.

Keywords

Kayan Kipli Kontrol, İleri Beslemeli PI, Akışkan Seviye Sistemleri, Doğrusal Olmayan Kontrol

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