Abstract: “We propose a robust non-fuzzy self-tuning scheme for fuzzy PI controllers (FPIC) for a class of systems. The output scaling factor (SF) of the proposed non-fuzzy self-tuning FPIC, termed as NF-STFPIC, is modified on-line based on the normalized change of error of the controlled variable. Performance of the proposed controller is evaluated for a pure integrating plus dead-time (IPD) and first-order integrating plus dead-time (FOIPD) processes with a wide variation in dead-time under both set-point change and load disturbance. Detailed performance comparison with conventional PI (both fuzzy and non-fuzzy) controllers as well as a self-tuning fuzzy PI controller (STFPIC) reported in the leading literature is provided with respect to a number of performance indices. Unlike STFPIC, which uses 49 expert's defined self-tuning fuzzy rules our NF-STFPIC uses a single deterministic rule. Experimental results justify the effectiveness of the proposed NF-STFPIC”

Keywords: Fuzzy logic controller, Self-tuning FLCs, Scaling factor, Integrating process.