Authors

Abstract

The selection of the three coefficients of proportional-integral (PID) controllers (Ki, Kp, and Kd) is basically a search problem in a three-dimensional space. This is so because points in the search space correspond to different selections of a PID controller’s three parameters. By choosing different points of parameter space, we can produce, for example, different step responses for a step input. A PID controller can be determined by moving in this search space on trial-and-error basis. The main problem in the selection of the three coefficients is that these coefficients do not readily translate into the desired performance and robustness characteristics that the control system designer has in mind. Several rules and methods using root locus and performance indices. The first design uses the Integral of Time multiplied by Absolute Error (ITAE) performance index. Hence we select the three PID coefficients (Ki, Kp, and Kd) to minimize the ITAE performance index, which produces a good transient response to a step input.
Our paper uses the Genetic Algorithm (GA). In this method the selection of the three PID coefficients depends on the minimization of the Mean Squared Error (MSE), which will produce an excellent transient response to a step input.

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