Optimized and automated synthesis of robust PID controller with quantitative feedback theory

Abstract

This study is motivated by the wide use of Proportional-Integral-Derivative (PID) controllers. In addition, the method of designing the PID controller can have a significant impact on its robustness. The potential of PID controller can be efficiently utilized only if it is tuned properly. We proposed a method of robust design of PID controllers for uncertain plant in the context of Quantitative Feedback Theory (QFT). The proposed method is applicable in the presence of different types of performance specifications-bringing to bear the full power of QFT. We have considered a new optimality criteria which delivers minimum gain of PID controller at each design frequency. The purpose of the proposed method is to automate the loop-shaping step of QFT design procedure for PID controller structure in the interval global optimization framework. The effectiveness of the proposed design method is illustrated through a variety of difficult design cases like resonant plant, open loop unstable plant and plant with variation in the time delay.