Factorial design for robustness evaluation of fractional PID controllers

This paper presents the factorial design for robustness evaluation between different PID controllers for the control of a nonlinear system with parametric uncertainties and presence of external disturbances. The comparison has been realized between the integer PID, fractional PID and PID SIMC controllers. The robustness analysis uses a factorial design of experiments. The factorial design has as input factors the uncertainty in the gain of the plant, the presence of random noise in the feedback loop, and the existence of external bounded disturbance. The outputs of the factorial design measure the performance of each PID control system using the response to Step Input and Control Action signal. The results show that the fractional PID controller has a better performance front to plant uncertain and an excellent rejection to external disturbances, which indicating a greater robustness of the process and lower power consumption.