OPTIMIZING PROPORTIONAL INTEGRAL DERIVATIVE WATER CONTROL SYSTEM TUNING BASED ON PARTICLE SWARM OPTIMIZATION Zahratul Laily Edaris *a , Syariza Abdul Rahman b a Department of Mechanical Engineering Politeknik Sultan Abdul Halim Muadzam Shah, Jitra, 06000, Kedah b Department of Decision Sciences, Faculty of Quantitative Sciences Universiti Utara Malaysia, Sintok, 06010, Kedah ABSTRACT: Tuning or adjusting the gain of (Proportional, Integral and Derivative) PID controller in a process control system is very important. This is due to that the correct tuning of process control contributes a control process response without steady state error and overshoot. Currently, there are many methods that are able to help the practitioners in tuning the right gain of a control loop. The conventional gain tuning of PID controller, Ziegler and Nichols technique usually produces a big overshoot, and therefore modern heuristics approaches such as Particle Swarm Optimization (PSO) are employed. In this study, algorithms determining the best PID controller parameters of a single tank water level control system using the Ziegler and Nichols technique and the PSO algorithm are presented. Comparisons of process time performance and the performance measurement of the system are made in order to evaluate both techniques in terms of their step response. The preliminary results show that the PSO technique gives promising results reducing the percentage figure of overshoot compared with the Ziegler and Nichols technique. It is found that the proposed PSO technique would be advantageous for the industries related with single tank water control system for a better PID gain tuning. KEY WORDS: Particle Swarm Optimization; PID Controller; Ziegler and Nichols; Single tank water level 1. INTRODUCTION Proportional Integral Derivative (PID) control is the three basic control modes widely used in plants and industrial processes such as in power plants, food and beverage, pharmaceutical, manufacturing and packaging applications (Astrom K.J. and Hagglund T. (1984)). The PID controller comprises three separate constant parameters, and it is also known as three-term control: the proportional, the integral and derivative values, denoted as P, I, and D. These values can be interpreted in terms of time: P depends on the present error, I on the accumulation of past errors, and D is a prediction of future errors based on current rate of change (Malhotra R., Singh N. and Singh Y. (2010)). Controllers are used in industry to regulate temperature, pressure, flow rate, chemical composition, speed and practically every other variable for which a measurement exists. It is important for any variable of the PID controller to be tuned accurately. Therefore, there are several techniques introduced for the process control tuning. The conventional techniques include those from Ziegler and Nichols and Cohen and Coon. Among the conventional PID tuning methods, the Ziegler and Nichols technique is the most well-known one (Ogata K. (1987)). Studies found that the Ziegler and Nichols technique is the most preferred by process control practitioners (Pillay N. and Govender P. INTERNATIONAL CONFERENCE ON THE ANALYSIS AND MATHEMATICAL APPLICATIONS IN ENGINEERING AND SCIENCE 19th-22nd Jan 2014, CSRI, Curtin University, Sarawak, Malaysia _________________________________________________________________________________________________________ 265