successfully achieved with the syst

successfully achieved with the systematic MF design. The designed MFranges also offered the best control performance at steady-state amongthe three cases tested, which indicates that the proposed systematicdesign approach for MFs is effective.4. ConcusionIn this paper, the effects of the range of MFs and sampling time oncontrol performance were examined in detail for the systematic designof a fuzzy control for VSRS, which is a typical nonlinear system. Theproposed range using the proposed approach and two different valuesfor each MF was tested in simulations and experiments. The resultsshowed that the MF ranges can be designed with control accuracy andwith data obtained in static and dynamic experiments. The main resultsof the simulations and experiments are summarized as follows: (1) The range of the error e marginally affects the steady-state responseof To and T due to the rapid saturation of the manipulated v ariableswhen the reference is suddenly changed. In addition, the smallerthe range of e, the greater the sensitivity to the steady-state error,resulting in a small oscillation of To and Ts at the steady-state.(2) The range of ee affects the transient response of Ta and Ts. The largerthe range of ee, the larger the magnitude of the manipulated vari-ables. As a result, the transient characteristics are improved.However, when Oe is extremely small in the steady-state, the re-sponse-characteristics were not affected.(3) Shorter sampling time ts caused the rapid increment of the ma-nipulated variables. Thus, the response of Ta and Ts quickly reachedthe target value. However, there was little change in the responsewith longer sampling times and the steady-state response was notaffected.