Current Issue : October - December Volume : 2012 Issue Number : 4 Articles : 6 Articles
We propose one networked control strategy for linear SISO systems affected by variant communication delays. The purpose of this\r\napproach is to adjust, by using the fuzzy logic, the command provided by the PID controller. The input for the fuzzy logic controller\r\n(FLC) is represented by the delay and the variation of delay, and the output is used to adapt the PID controller�s command to the\r\nnew value of the communication delay which occurs in the network. Simulation and implementation results are presented. The\r\nresults show performance improvement when using our control strategy. The authors present the implementation for an axis of a\r\n3D crane, using the Ethernet/IP (TCP/IP) communication protocol....
In recent years, many fuzzy time series methods have been proposed in the literature. Some of these methods use the classical fuzzy\r\nset theory, which needs complex matricial operations in fuzzy time series methods. Because of this problem, many studies in the\r\nliterature use fuzzy group relationship tables. Since the fuzzy relationship tables use order of fuzzy sets, the membership functions\r\nof fuzzy sets have not been taken into consideration. In this study, a new method that employs membership functions of fuzzy sets\r\nis proposed. The new method determines elements of fuzzy relation matrix based on genetic algorithms. The proposed method\r\nuses first-order fuzzy time series forecasting model, and it is applied to the several data sets. As a result of implementation, it is\r\nobtained that the proposed method outperforms some methods in the literature....
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The fuzzy symmetric solution of fuzzy matrix equation A X = B, in which A is a crisp mÃ?â??m nonsingular matrix and B is an mÃ?â??n\r\nfuzzy numbers matrix with nonzero spreads, is investigated. The fuzzy matrix equation is converted to a fuzzy system of linear\r\nequations according to the Kronecker product of matrices. From solving the fuzzy linear system, three types of fuzzy symmetric\r\nsolutions of the fuzzy matrix equation are derived. Finally, two examples are given to illustrate the proposed method....
The hybrid recurrent fuzzy neural network (HRFNN) control for permanent magnet synchronous motor (PMSM) drive system\r\nusing rotor flux estimator is developed to control electric scooter in this paper. First, the dynamic models of a PMSM drive system\r\nwere derived in according to electric scooter.Owing to the load of electric scooter exited many uncertainties, for example, nonlinear\r\nfriction force of the transmission belt, and so forth. The electric scooter with nonlinear uncertainties made the PI controller to\r\ndisable speed tracking control. Moreover, in order to reduce interference of encoder and cost down, an HRFNN control system\r\nusing rotor flux estimator was developed to control PMSM drive system in order to drive electric scooter. The rotor flux estimator\r\nconsists of the estimation algorithm of rotor flux position and speed based on the back electromagnetic force (EMF) in order to\r\nsupply with HRFNN controller. The HRFNN controller consists of the supervisor control, RFNN, and compensated control with\r\nadaptive law is applied to PMSM drive system. The parameters of RFNN are trained according to different speeds in electric scooter.\r\nThe electric scooter is operated to provide disturbance torque. To show the effectiveness of the proposed controller, comparative\r\nstudies with PI controller are demonstrated by experimental results....
Fuzziness is found everywhere, in modeling spatial relations, fuzziness is found at object level as well as in relation semantics.\r\nCommonly, fuzzy topological relations are computed between fuzzy objects. Fuzziness in relation semantics is represented by fuzzy\r\ntopological relations between crisp objects and these types of fuzzy topological relations are much less developed. In this paper, we\r\npropose a method for combining fuzzy topological and directional relations. We also propose an algorithm for defuzzification of\r\nrelations which provides us a binary topological and directional relation between a 2D object pair. These relations are represented\r\nin a neighborhood graph. For validation and assessment, a number of experiments have been performed on artificial data....
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