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Showing 3 results for Nourizade
Volume 16, Issue 9 (11-2016)
Abstract
In this paper, designing optimal linear controller for non-holonomic wheeled mobile robots based on Linear Quadratic Gaussian (LQG) controller is considered. Parameters of the governing kinematics equation of motion are derived based on system identification techniques by using real experimental data. The autoregressive moving average-exogenous input (ARMAX) models are taken into account. The least square (LS) algorithm is utilized to estimate the parameters of the model. Thereafter, optimal model order and the performance of the model are determined using several statistical analyses. Also, the recursive LS (RLS) with forgetting factor is employed to demonstrate the convergence of the model parameters. Verification of discrete linear model implies the possibility of using the linear controllers. Therefore, the optimal LQG controller for wheeled mobile robots is designed to track the reference trajectory. The Kalman observer is used to estimate un-measurable states of the robot. Furthermore, the optimal linear control together with system identification techniques yields simpler controller than nonlinear controllers. Designed controller and verified model are simulated using the MATLAB-Simulink software. Results show the effectiveness of the controller in tracking the desired reference trajectory.
Farhad Ghorbandordinejad, Farhad Nourizade,
Volume 22, Issue 4 (10-2015)
Abstract
This study is intended to examine the relationship between critical thinking disposition and English learning achievement among Iranian high school third-grade EFL learners mediated by emotional intelligence. A sample of 264 students (145 males and 119 females) was assessed for their level of critical thinking disposition and emotional intelligence. Participant's scores on their final English test were also used as the measurement of their English achievement. The results revealed a positive correlation between total critical thinking dispositions (r=.506, p<.01) and its subscales i.e., engagement(r=.33), maturity(r=47), and innovativeness (r=44.6) with English learning achievement. The results also suggested that emotional intelligence acts as a mediator of the relationship between critical thinking disposition and English learning achievement.
Volume 22, Issue 8 (August 2022)
Abstract
Tool wear has a significant influence on the turning process. Investigations on tool wear monitoring through various methods and sensors have been widely conducted to determine and predict the tool wear. In this study sound generation mechanisms during turning process have been investigated comprehensively and three sound generation sources have been determined and distinguished. Sound generation mechanisms which originated from tool vibration, deformation in the workpiece and vibration at the contact zones (friction), have been investigated and frequency range of the sound generated through each mechanism has been determined. It has been shown that these mechanisms produce sound in 10s hertz, kilohertz and megahertz respectively. Then the mechanism which is appropriate for tool condition monitoring has been studied and suggested. Then the relation between the sound generation mechanisms and chip formation has been studied during machining. Hence, a deep understanding about the machining process has been brought out. Findings could lead to an effective approach to monitoring the machining process, not only using mathematical signal processing methods, but also through a physical comprehension background. Experimental studies have been conducted to evaluate developed theories and models. Experimental results have shown effectiveness of the proposed approach.
