Fuzzy Logic Control of Switched Reluctance Motor Drives

In this chapter, the electromechanical behavior of switched reluctance motor (SRM) is first modeled by analyzing the related nonlinear differential equations. In the model, the estimation of rotor speed is also considered. After modeling, the effects of torque ripple, radial force, and acoustic noise are investigated. As we know, torque ripple and acoustic noise are two of the main disadvantages of a switched reluctance motor. Thus, a fuzzy logic current compensator is proposed both for reducing the peak of radial force and for decreasing acoustic noise effects. In the parts that torque reduces, the fuzzy logic current compensator injects additional current for each phase current to overcome the torque ripple. Also, the fuzzy logic current compensator reduces speed estimation error. The speed estimation is carried out using a hybrid sliding mode observer which estimates the rotor position and speed for a wide speed range. These new approaches have been simulated using MATLAB/SIMULINK for a nonlinear model of switched reluctance motor. The simulation results indicate that proposed methods decrease the maximum radial force and the torque ripple while the maximum torque is preserved. Also, these results show that proposed methods will estimate the rotor position and speed with high precision for all speeds from near zero speeds up to rated speed. These procedures have the advantages of simple implementation on the every switched reluctance motor drive without extra hardware, low cost, high reliability, low vibration, and excellent performance at long term

THE DESIGN OF ADJUSTABLE RADIO FREQUENCY FILTER (RF) BY USING MICROSTRIP LINE TECHNOLOGY

Abstract. Nowadays, filters are the main component of communication systems. Often they are used toselect certain frequencies. Filters usually plays a key role in choosing or limiting the radio frequency signals.Compressed midrange filters are constructed by using in-line digital microstrip lines on composite lenses suitable for high frequencies with over 6,000 sub-layers. BFP microstrips, 1.69 / 2.3GHz dual-state dual-band 1.69 / 2.3GHz, are the new generation of microstrips that have just been introduced. In the present study, the performance of this type of microstrip was simulated. To simulate the BFP efficiency with different makeups, a set of simulations was performed based on HFSS. After examining a few cases, the study of the relationship between different parameters has been investigated. Finally, after examining different modes, the conclusions were discussed. The proposed filter design method can be very suitable for designing the receiver module and compact transmitter.Keywords: microstrip, radio filter, intermediate frequency band pass filter, biaxial filter and double-sided

A Study on the relation between height of medial longitudinal arch and sport injuries in lower limb of professional runners by using Navicular Drop and Arch Index clinical tests

Abstract: Understanding foot-to-ground contact is not simple due to sophistication of its structure. Plantar pressure measurement devices may be a proper device for determining foot structural situation. The results of the present paper reveal that change in the foot structure, particularly the medial longitudinal arch, may increase probability of injury. Association of pathologic biomechanical changes of foot with an activity such as running that increases the ground reaction force up to 5 times more than the body weight is still among the most important discussed issues. This paper is aimed at studying the effect of longitudinal arch of foot on the sport injuries in professional runners and studying the relation between navicular drop clinical test and plantar pressure measurements (pedobarography). 47 professional runners were selected from Sabzevar City and divided into three groups namely, normal, low arched, and high arched runners by using navicular drop test. Also by using emed-x system, maximum force, peak pressure, and contact area parameters in two static and dynamic postures were measured and recorded. 2x test showed no relation between running injuries and arch height (P=0.58). Correlation between navicular drop clinical test and modified arch index calculated from pedobarography measurements in two static and dynamic postures was between 0.32 and 0.57. Due to multi factorial nature of running injuries, changes in the arch height may not increase risk of injury. Although there was not a very high correlation between navicular drop test and plantar measurements, the obtained correlation is a good correlation since this test is clinical. Despite prior studies differentiate static posture (standing on both feet) from dynamic situation, but it seems that plantar pressure distribution in the static posture of single limb support may have a great similarity with functional situation of walking

Stability Prediction Of Quadruped Robot Movement Using Classification Methods And Principal Component Analysis

This paper introduces a novel technique for predicting the stability of quadruped robot locomo- tion using a central pattern generator (CPG). The proposed method utilizes classification methods and principal component analysis (PCA) to predict sta- bility. The objective of this study is to anticipate the stability or instability of robot movement by mod- ifying controlling parameters, referred to as features. The simulations of robot locomotion are conducted in MATLAB/SIMULINK R©, generating a dataset of 82 observations with different parameters. Machine learn- ing (ML) techniques are then applied, using classi- fication methods and PCA, to determine the stabil- ity condition. Six classification methods, including K-nearest neighbors (KNN), support vector classifier (SVC), Gaussian Naïve Bayes (GaussianNB), logistic regression (LR), decision tree (DT), and random for- est (RF) are implemented using Scikit-learn, an open- source ML library in Python. The performance of these classifiers is evaluated using four metrics: precision, recall, accuracy, and F1-score. The results indicate that KNN and SVC exhibit higher metric values com- pared to the other classifiers, making them more effec- tive for stability prediction

Alignment of Business Strategies and Human Resource Strategies in Banking Industry

The present study aimed to "align business strategies with HRM strategies in the banking industry." By reviewing theoretical basis, previous studies and existing documents, business strategies available in the three positions of the Delta model were identified in the banking industry, and they were mitigated and interpreted using banking experts' opinions. Then, using the matching alignment approach from among the Venkaterman approach models , and by the use of alignment model of reference strategic points, adaptation is made between the strategies available in each position and the strategies of the Bamberger and Meshoulam model, which  itself was used as the model for determining the human resource strategy in this study. Thus, appropriate human resource strategies were identified for each business strategy in the three positions. The sampling method was a combination of non-probability sampling methods of snowball and judgment. These methods were chosen because of the specific information each step requires, the lack of familiarity of the researcher with experts in the related areas and the limited number of these people

Increasing the Liquidus Temperature by Employing the Controlled Diffusion Solidification (CDS) Process: A Potential Route to Improved Castings

Abstract Recent theories suggest the existence of an incubation time, over which a liquid alloy prepares for nucleation by decomposing into compositional fluctuations. Accordingly, in a recent work by the present authors, the solidification path of a Controlled Diffusion Solidification (CDS) mixture was calculated. The calculated CDS path begins at a higher liquidus temperature comparing to conventional solidification and the fraction solid values are achieved at a relatively higher temperature. To provide information on the CDS mechanism and physical structure of the CDS mixture in the mushy zone, Al-7.8Zn-2.6Mg-2Cu alloy was solidified, in this study, via conventional and CDS process in the presence and absence of recalescence. Typical grain structures obtained via the two solidification conditions is characterized using Electron Back Scattered Diffraction. Results showed that the nucleation continues to occur in the presence of recalescence, while it is suppressed in its absence. According to the two step nucleation theory, the increase in the nucleation temperature causes sufficient recalescence in the mixture, allowing the unnucleated liquid phase to decompose into chemical fluctuations and prepares for further nucleation. As a result, in the presence of recalescence, nucleation in a CDS mixture is not as readily halted as during the conventional solidification, which is in contradiction with the recent theories developed based on the classical theory of nucleation