Modeling and Controller Design for a Coupled–Tank Liquid Level System: Analysis & Comparison

Abstract

Sistem yang diuji ialah tangki berkembar yang biasa digunakan dalam proses kawalan industri. Prinsip asas sistem tangki berkembar adalah untuk mengekalkan paras cecair di dalam tangki pada suatu nilai tetap apabila wujud aliran keluar masuk cecair dalam tangki. Analisis tindak balas langkah, analisis pseudorandom binary sequence (PRBS) dan kaedah least square digunakan untuk mengklasifikasikan sistem ini. Objektif utama projek ini adalah untuk menentukan model matematik sistem tangki berkembar menggunakan tiga teknik tesebut. Ia diikuti dengan mereka bentuk pengawal yang terdiri daripada pengawal PID dan pengawal Fuzzy Logic untuk sistem ini. Pada peringkat akhir projek ini, penggunaan kedua-dua pengawal dalam aplikasi industri dibandingkan dan dianalisa. Kata kunci: Pengenalpastian sistem, tindak balas langkah, pseudorandom binary sequence, kaedah least square, pengawal Fuzzy Logic & PID The system under investigation is a coupled-tank apparatus which is a laboratory bench top emulation of a common process in industrial control. The basic control principle of the coupled-tank system is to maintain a constant level of the liquid in the tank when there is an inflow and outflow of water in the tank and outflow of water out of the tank respectively. Classification of this system using system identification technique involved the transient response analysis, the pseudorandom binary sequence (PRBS) analysis and the least square method. The main objective of this project is to determine the mathematical model of a coupled-tank system using these techniques. It follows by designing a controller consists of a PID and a Fuzzy Logic controllers for the system. At the final stage of this project, the usage of both controllers in industrial applications is compared and analyzed. Key words: System identification, step response, pseudorandom binary sequence, least square method, PID & Fuzzy Logic controller