Design Method for Robust PI-like Process Fuzzy Logic Controller

The industrial applications of fuzzy logic controllers (FLC) for complex, nonlinear, time varying processes with time delay mark a considerable progress. It is inspired by the recent theoretical achievements in the FLC’s design and tuning related to system stability and robustness. The design and the FLC simplicity are of crucial importance. There exists an easy design and tuning procedure for a simple single input fuzzy controller (SI FC) that ensures fuzzy system stability and robustness. The SI FC, however, loses some of the richness of the behaviour of the ordinary FLC. The aim of the present investigation is to develop a simple design method for incremental PI-like ordinary FLCs on the basis of the SI FC approach, ensuring stability and robustness in the closed loop system for the control of industrial plants with time delay and model uncertainty. The main contributions are: 1) a design method for FLC, based on modification of the SI FC stability and robustness approach; 2) FLC tuning algorithm. The results are applied for the stabilisation of the air temperature in a furnace using MATLABTM. The advantages of the designed SI FC system are assessed in comparison with SI FC control system via simulations. Key-Words: frequency domain incremental PI-like process FLC design, MATLAB, robust stability and performance, temperature control, time delay, tuning algorithm