Fuzzy control methods are developed for a high efficient variable speed constant frequency power generating system, with wind power generation as an example. In slip power recovery configuration, the system is composed of a doubly excited brushless reluctance machine and a reduced rating power electronic converter unit linking the stator secondary circuit with the power line. The doubly excited...

chaotic systems are nonlinear dynamic systems, the main feature of which is high sensitivity to initial conditions. to initiate a design process in fuzzy model, chaotic systems must first be represented by t-s fuzzy models. in this paper, a new fuzzy modeling method based on sector nonlinearity approach has been recommended for chaotic systems relating to initial condition variations using the ...

In this work a motion control scheme, which belongs to the class of the control schemes known as a sliding mode control with disturbance estimation is proposed. Adaptive fuzzy disturbance estimator works as an identifier of variable part of a system dynamics. Adaptation algorithm is derived by using the Lyapunov stability theory and provides global asymptotic stability of the state errors. For ...

Fuzzy random variables possess several interpretations. Historically, they were proposed either as a tool for handling linguistic label information in statistics or to represent uncertainty about classical random variables. Accordingly, there are two different approaches to the definition of the variance of a fuzzy random variable. In the first one, the variance of the fuzzy random variable is ...

The information systems with incomplete attribute values and fuzzy decisions commonly exist in practical problems. On the base of the notion of variable precision rough set model for incomplete information system and the rough set model for incomplete and fuzzy decision information system, the variable rough set model for incomplete and fuzzy decision information system is constructed, which is...

According to the current literature, there are two different approaches to the definition of the variance of a fuzzy random variable. In the first one, the variance is defined as a fuzzy interval, offering a gradual description of our incomplete knowledge about the variance of an underlying, imprecisely observed, classical random variable. In the second case, the variance of the fuzzy random va...

Double sampling plan is an examination with a certain parameter, so it cannot decide about manufactured products whose portion parameter ( ) is not certain. The main goal of this survey is to introduce double variable plan when  is indefinite to examine manufacturing products when concerned characteristics are normally distributed. Plan parameters are achieved by an optimization manner. Sum of ...

In the paper, a fuzzy variable structure control with a harmonizing mechanism has been developed and applied to the positioning control of an electro-hydraulic servo system. The simulation experiment results show that the performance by using the controller is better than those by just only using either fuzzy controller or variable structure controller. In addition, it also demonstrates that it...

We recall the concept of a linguistic variable and the representation of its values (i.e. linguistic terms) by means of fuzzy sets. In this framework adverbs are represented by fuzzy modifiers, i.e. operators acting on these fuzzy sets. We investigate two important classes of popular fuzzy modifiers. Grounding on results from psycholinguistic research, we discuss their pro’s and contra’s for re...

Given a fuzzy variable, what is the degree of difficulty of predicting the specified value that the fuzzy variable will take? Entropy provides a measure to characterize the fuzziness. Given some constraints, there are usually multiple compatible membership functions. Which membership function shall we take? The maximum entropy principle attempts to select the membership function that maximizes ...