Parameter tuning of multiple PID controllers by using iterative feedback tuning

Abstract

This paper provides an application of Iterative feedback tuning (IFT) that adjusts controller parameters of multiple PID controllers installed in a bIIM0 process. In process indus- tries, PID controllers are widely used. Although the PID controller has a simple structure and has only three tuning parameters, it is hard work to find adequate parameters. IFT is a direct tuning method using closed-loop experimental data. This method is based on a numerical optimization of minimizing a specified cost function. In each iteration, a value and a gradient estimate of the cost function is obtained by use of experimental data. IFT is applied for tuning of two PID controllers that are used in a AIIhIO process which has two inputs and two outputs. In order to evaluate the IFT method, experimental tests are conducted and show results.