Iterative Feedback Tuning Approach to Development of PI-Fuzzy Controllers

The paper proposes an original development method of Pi-fuzzy controllers. Accepting the controlled plants being described with simplified linear mathematical models, the method starts with linear PI controller development in terms of Iterative Feedback Tuning expressed in discrete-time. It is accompanied by a linear development method applied in delta domain. Next, the results of the linear development are transferred to the development of the fuzzy blocks in PI-fuzzy controllers by the modal equivalence principle, resulting in new two-degree-of-freedom Mamdani Pi-fuzzy controllers. Realtime experimental results in controlling a nonlinear servo-system validate the development method, where the linear development is performed using the Extended Symmetrical Optimum method.