Chattering-Free Robust Adaptive Sliding Mode Speed Control for Switched Reluctance Motor

This study describes an adaptive sliding mode control (ASMC) for the control of switched reluctance motor (SRM). The main objective is to minimize torque ripples with controller effort smoothness while the system is under perturbation by structured uncertainties, unknown parameters, and external disturbances. The control algorithm employs an adaptive approach to remove the need for prior knowledge within the bound of perturbations. This is suitable for tackling the chattering problem in the sliding motion of ASMC. In order to achieve control effort smoothness and more effective elimination of chattering, the algorithm then incorporates proper modifications in order to build a chattering-free robust adaptive sliding mode control (RASMC) using Lyapunov stability theory. A final advantage of the algorithm is that system stability and error convergence are guaranteed. The effectiveness of the proposed controller in improving robustness and minimizing ripples is demonstrated by numerical simulation. Experimental validation is used to demonstrate the efficiency of the proposed scheme. The results indicate that RASMC provides a superior performance with respect to speed tracking and disturbance rejection over the conventional sliding mode control (CASMC) in the face of uncertainties in model and dynamic loads

DIGITAL OPTIMAL CONTROL OF MULTI-STAND ROLLING MILLS WITH MEASUREMENT AND INPUT DELAYS

In this paper, the problem of designing an optimal control algorithm for rolling processes is addressed. Deriving a mathematical model for a general class of rolling mills, the optimal control problem is defined. In the design procedure, time delays in thickness measurement and control input are taken into account. The proposed strategy significantly improves the results of previous investigations from practical point of view. Simulation results are also studied to highlight the effectiveness of the method

Stabilization of DC–DC buck converter with unknown constant power load via passivity-based control plus proportion-integration

Abstract It is known that constant power load (CPL) may cause a negative impedance, which seriously affects the stability of power system. In this paper, a new control algorithm for DC–DC buck converter feeding unknown CPL is proposed. First, under the assumption of known extracted power load, the standard passivity–based control (PBC) is presented to reshape the system energy and compensate for the negative impedance and a proportion‐integration (PI) action around passive output is added to improve disturbance rejection performance, which forms the PBC plus PI (PBC+PI). Then, a parameter estimation algorithm is developed, based on immersion and invariance (I&I) technique, in order to online estimate the extracted power load. In the next step, the online estimation scheme is adopted to construct an adaptive strategy. Finally, the stability analysis of the cascaded system containing a closed‐loop control system and observer error dynamics is conducted. Simulation and experimental results are demonstrated to validate the performance of the proposed controller

Compiling a Model of Managers' Professional Meritocracy Based on Islamic and Iranian Teachings

The purpose of this study is to develop a model of professional meritocracy of managers based on Iranian and Islamic teachings. The research method is mixed (qualitatively quantitative) of the type of successive exploratory designs. In the qualitative section, using the library method and mining texts, the concepts related to the indicators of professional competence of organizational managers were examined. The statistical population in this section was 47 educational management experts who were selected by purposive sampling method and using the analysis of semi-open interview results and content analysis method, concepts were drawn in the form of a network of themes. The tools for collecting research information in the qualitative section were sources, interviews and documents (research reports, etc.) that the participatory feedback method was used to validate the validity and reliability analysis. In order to analyze the qualitative data, inductive content analysis based on open coding was used. In the quantitative part, data collection was based on a researcher-made questionnaire. In this part, a one-sample t-test was used and the statistical population of this section was 213 And were bred in Bushehr province that multi-stage cluster sampling method was used to select quantitative statistical samples. To validate the reliability of the questionnaire in this section, Cronbach's alpha coefficient was used, the reliability of which was 0.78, and its face and content validity was confirmed by experts. Data analysis in the qualitative domain was based on content analysis and in the quantitative domain was done using statistical software and factor analysis method. The results showed that the development of human resource management model with qualification criteria in accordance with Islamic and Iranian teachings, organizational planning based on "competence", matching capabilities and competencies with jobs and managements should be done carefully and only under legal and ethical criteria.El propósito de este estudio es desarrollar un modelo de meritocracia profesional de los gerentes basado en las enseñanzas iraníes e islámicas. El método de investigación es mixto (cualitativamente cuantitativo) del tipo de diseños exploratorios sucesivos. En el apartado cualitativo, utilizando el método bibliotecario y los textos mineros, se examinaron los conceptos relacionados con los indicadores de competencia profesional de los gerentes organizacionales. La población estadística en esta sección fue de 47 expertos en gestión educativa que fueron seleccionados mediante el método de muestreo intencional y utilizando el análisis de los resultados de la entrevista semiabierta y el método de análisis de contenido, los conceptos se dibujaron en forma de una red de temas. Las herramientas para la recolección de información de investigación en el apartado cualitativo fueron fuentes, entrevistas y documentos (informes de investigación, etc.) que se utilizó el método de retroalimentación participativa para validar el análisis de validez y confiabilidad. Para el análisis de los datos cualitativos se utilizó el análisis de contenido inductivo basado en codificación abierta. En la parte cuantitativa, la recolección de datos se basó en un cuestionario elaborado por investigadores. En esta parte, se usó una prueba t de una muestra y la población estadística de esta sección fue de 213 Y fueron criados en la provincia de Bushehr que se utilizó el método de muestreo de conglomerados de etapas múltiples para seleccionar muestras estadísticas cuantitativas. Para validar la confiabilidad del cuestionario de este apartado se utilizó el coeficiente alfa de Cronbach, cuya confiabilidad fue de 0,78, y los expertos confirmaron su validez de cara y contenido. El análisis de datos en el dominio cualitativo se basó en el análisis de contenido y en el dominio cuantitativo se realizó mediante software estadístico y método de análisis factorial. Los resultados mostraron que el desarrollo de un modelo de gestión de recursos humanos con criterios de calificación de acuerdo con las enseñanzas islámicas e iraníes, la planificación organizativa basada en la "competencia", la adecuación de las capacidades y competencias con los puestos y la gestión debe realizarse con cuidado y solo bajo criterios legales y éticos

DESIGN OF ROBUST COMMAND TO LINE-OF-SIGHT GUIDANCE LAW: A FUZZY ADAPTIVE APPROACH

In this paper, the design of command to line-of-sight (CLOS) missile guidance law is addressed. Taking a three dimensional guidance model, the tracking control problem is formulated. To solve the target tracking problem, the feedback linearization controller is first designed. Although such control scheme possesses the simplicity property, but it presents the acceptable performance only in the absence of perturbations. In order to ensure the robustness properties against model uncertainties, a fuzzy adaptive algorithm is proposed with two parts including a fuzzy (Mamdani) system, whose rules are constructed based on missile guidance, and a so-called rule modifier to compensate the fuzzy rules, using the negative gradient method. Compared with some previous works, such control strategy provides a faster time response without large control efforts. The performance of feedback linearization controller is also compared with that of fuzzy adaptive strategy via various simulations

Computing frequency response of non‐parametric uncertainty model of MIMO systems using υ‐gap metric optimization

Abstract This paper presents the computation of the non‐parametric uncertainty model for multi input multi output (MIMO) systems, which is described by normalized coprime factors (NCF) using the frequency response data of the system. This computation is accomplished by minimizing a υ‐gap metric criterion. For this purpose, the problem is formulated to a convex optimization context, such that a semidefinite programming (SDP) can be implemented. Minimization constraints and the normality constraints of coprime factors are converted to linear matrix inequalities (LMI). Thus, by convex optimization algorithms, the semidefinite programming will be optimized. The proposed method can also be used for non‐square multi input multi output systems in a conservative assumption. So, through the first process of optimization, the frequency responses of the normalized coprime factors are derived. Finally, to evaluate the performance of the proposed method in the computation of the normalized coprime factors of a system, the simulated results of this method are compared with those obtained by the other methods for two types of systems