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Performance Comparisons of EWMA Control Chart Schemes

QUALITY TECHNOLOGY AND QUANTITATIVE MANAGEMENT 2010年第3期7卷 249-261页

作者： Simoes, Bruno F. T. Epprecht, Eugenio K. Costa, Antonio F. B. Pontif Catholic Univ Rio de Janeiro PUC Rio Dept Ind Engn Rio De Janeiro Brazil Sao Paulo State Univ UNESP Dept Prod Guaratingueta SP Brazil

Combining an EWMA chart with a Shewhart chart is traditionally recommended as a means of providing good protection against both small and large shifts in the process mean. Capizzi and Masarotto have proposed an EWMA chart with a variable smoothing constant (AEWMA) for the same purpose. In this paper, we optimize the designs of the AEWMA and of the combined EWMA-Shewhart schemes with regard to pairs of shifts in the process mean and compare their performances. When the schemes are optimized for the same pair of shifts, their ARL profiles practically coincide. The choice between the AEWMA and the EWMA-Shewhart scheme then becomes a matter of personal preference. We also explore using an AEWMA together with a Shewhart chart, but we find no performance improvement. An additional contribution of this paper is the tables of optimal designs of each scheme for several pairs of shifts.

关键词： Adaptive control charts ARL profiles exponentially weighted moving average statistical process control variable parameters variable smoothing constant

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Analysis of systems with variable parameters and robust control design

Analysis of systems with variable parameters and robust cont...

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6th International Conference on Modelling, Simulation, and Optimization

作者： Yanev, Kamen Univ Botswana Gaborone Botswana

ISBN: (纸本)9780889865914

Control systems must yield performance that is robust or insensitive to parameter variations. In the process of design of a robust control system, it is important to determine the regions of stability, corresponding to the variation of a specific system parameter. The purpose of this paper is to apply the method of the D-partitioning [1], in order to analyze the effects of parameter variations on system's stability. The method employs the possibility to define regions of stability in the space of the system's parameters. One of the contributions of this research is to simplify and graphically determine the regions of stability for variation of a specific system parameter. Further to this analysis, the paper contributes in suggesting a strategy of design of a robust control system. Preference is given to the design of a robust controller, since robustness with the conventional feedback configuration is achieved only with a very high loop gain, normally detrimental to stability. A real-life control system is subjected to analysis and design of a robust control is considered.

关键词： robust variable parameters stability regions system

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The Application of Integral variable Structure Control in Cutting-in Control of Double-fed Induction Generator

The Application of Integral Variable Structure Control in Cu...

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4th IEEE Conference on Industrial Electronics and Applications

作者： Hou Guo-Lian Wang Ruiqiao Zhang Jianhua NCEPU Dept Automat Beijing Peoples R China

ISBN: (纸本)9781424427994

In order to achieve the target of no-load cutting-in smoothness and security of double-fed induction wind generator, a control strategy based on combination of integral variable structure control and field-oriented vector control is presented. So as to get a better dynamic performance and robustness in disturbance, the sliding model variable structure controller is used to control rotor current before cutting-in on the basis of establishment of wind turbine model with variable parameters. For the chattering of current, produced by variable structure control, the saturation function is employed to switch control and the integral transform is used to eliminate steady-state error, which can make the system produce quasi slide mode movement and reduce the distortion rate of controlled voltage. Finally, the proposed method is simulated with MATLAB/simulink and the results shows that the method can control the variable-parameters wind turbine model robustly.

关键词： sliding variable structure control double-fed induction generator no-load cutting-in variable parameters integral transform

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SPC techniques for non Gaussian processes

SPC techniques for non Gaussian processes

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13th ISSAT International Conference on Reliabitity and Quality in Design

作者： Babus, Florina Tiplica, Teodor Kobi, Abdessamad Bacivarov, Ioan Univ Angers ISTIA LASQUO F-49000 Angers France

ISBN: (纸本)9780976348627

This paper presents a study on the statistical control methods for non Gaussian processes. Particularly, we analyze the processes that involve asymmetric or one bounded distributions. The control chart with variable parameters (VP) is proposed as a solution to the inherent problems of inspection of mechanical parts, which occur in many industrial fields, like aeronautics or automobiles. There are not many studies which can offer high-quality solutions concerning the control methods for the non gaussian processes not either for the category of asymmetric distributions. Considering its practical incidence in the processes of inspections, when the geometry specifications of parts are to be strongly respected, a study on the Rayleigh distribution is advanced. The results of the VP chart application are compared with the ideal, theoretical results, obtained by using the quartile estimation. The numerical simulations confirm and support the improvement of the SPC tools when the distributions are unknown or non gaussian.

关键词： SPC non Gaussian Rayleigh variable parameters

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Modeling and optimum design of disk-type hysteresis motors

Modeling and optimum design of disk-type hysteresis motors

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International Conference on Electrical Machines and Systems

作者： Darabi, Ahmad Lesani, Hamid Ghanbari, Teimoor Akhavanhejazi, Amirabbas Shahrood Univ Technol Fac Elect & Robot Engn Shahrood Iran Univ Tehran Fac Elect & Comp Engn Control Intelligent Syst Tehran Iran

ISBN: (纸本)9788986510089

In this paper, calculation of electrical equivalent circuit parameters versus design parameters of high frequency disk-type hysteresis motors are presented in details for steady state operating conditions. It is demonstrated that some of the equivalent circuit parameters alter significantly with input voltage and for different operating conditions. Therefore an equivalent circuit with fixed elements may give an inaccurate prediction of the steady state performance of a machine in many circumstances. Furthermore in this paper for a disk-type hysteresis motor which is designed and manufactured by use of variable parameter model, a sensitivity analysis is presented and influences of some design parameters on machine performances are discussed.

关键词： hysteresis motor disk-type modeling equivalent circuit variable parameters sensitivity analysis

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Modeling and Optimum Design of Disk-Type Hysteresis Motors

Modeling and Optimum Design of Disk-Type Hysteresis Motors

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International Conference on Electrical Machines and Systems 2007(ICEMS2007)(第十届国际电机与系统会议)

作者： Amirabbas Akhavanhejazi Teimoor Ghanbari Ahmad Darabi Hamid Lesani Faculty of Electrical and Robotic Engineering Shahrood University of Technology Iran Control and Intelligent System Faculty of Electrical & Computer Engineering University of Tehran

关键词： Hysteresis Motor Disk-Type Modeling,Equivalent Circuit variable parameters Sensitivity Analysis.

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Adsorption studies of iron(III) on chitin

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JOURNAL OF CHEMICAL SCIENCES 2005年第6期117卷 663-672页

作者： Karthikeyan, G Andal, NM Anbalagan, K Deemed Univ Gandhigram Rural Inst Dept Chem Gandhigram 624302 India

Adsorption of ferric ions by chitin was studied by the batch equilibration method. The influence of particle size and dosage of the adsorbant, contact time, initial concentration of the adsorbate and temperature were experimentally verified. The effect of anions like chloride, nitrate and sulphate and also of cations like zinc, chromium and copper on the adsorption of iron(III) was determined. The time dependence of fraction of adsorption, Y-t, at varying particle sizes and doses of chitin and the intraparticle diffusion rate constants, k(p), of the adsorption process were calculated. Thermodynamic and equilibrium parameters of the reaction were determined to understand the sorption behaviour of chitin. The results revealed that the adsorption of iron(III) by chitin is spontaneous, endothermic and favourable.

关键词： adsorption chitin variable parameters fraction of adsorption temperature effect

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A based on DSP digital controlled high switching frequency and constant charging current system

A based on DSP digital controlled high switching frequency a...

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IEEE Pacific Rim Conference on Communications Computers and Signal Processing (PACRIM 2003)

作者： Chao, ZY Xu, ZX Zhong, HQ Huazhong Univ Sci & Technol Dept Elect Engn Wuhan 430074 Hubei Peoples R China

ISBN: (纸本)0780379780

This paper presents a new design method based on DSP control and the PI algorithm of integral separation and variable parameters for constant current battery charging system, The structure and principle of the main circuit, control strategy and software design are introduced in detail. A two-step charging pattern of battery is adopted in this system. In this charging pattern, charging current, charging time, charging principle and terminating conditions of two charging steps can be separately set ahead, and it can realize smooth conversion from the first charging step to the second. The full digital control is realized by DSP chip TMS320F240. This system has been used for charging 12V or 24V battery with constant current in 2Asimilar to36A. The experimental result shows this charging system has both good steady-state performance and good dynamic performance.

关键词： variable parameters integral separation constant current charging DSP

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On-line identification and compensation-based model reference adaptive neural network speed control for LPMSM

On-line identification and compensation-based model referenc...

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7th International Workshop on Advanced Motion Control

作者： Guo, QD Xie, DM Shenyang Univ Technol Sch Elect Engn Shenyang Peoples R China

ISBN: (纸本)0780374797

Under the condition that the object model is definite, unvaried, and linear and that the operation condition and environment is ascertained, it is efficient to adopt traditional control scheme. But for the situation of high precision and fine feed, the timing and variable factors such as the variation of structure and parameters of the object, the effects of all kinds of nonlinear factors, the changes of operation environment and environmental interferes must be considered to obtain satisfying control effect. Nowadays modern control schemes are taken seriously in the study of LPMSM In this paper, we propose a control scheme for the speed servo control of LPMSM with model reference adaptive and neural network techniques. Model reference adaptive neural network control is a new technique which is the combination of the model reference adaptive control and the neural network control. This kind of control method has double advantages of the two methods. To improve the robustness of the system, we use on-line identification technique to compensate the variation of the parameters and modify the calculation of the neural networks teacher value. The result of simulation shows that the system has good speed servo performance, especially in overcoming the end effect of LPMSM..

关键词： linear synchronous motors permanent magnet motors machine control control system synthesis velocity control model reference adaptive control systems neurocontrollers machine theory control system analysis computing electric machine analysis computing robust control compensation identification linear permanent magnet synchronous motor model reference adaptive neural network speed control online identification online compensation variable structures variable parameters speed servo control robustness improvement control simulation computer simulation current control action compensation

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Modeling of glycerol production by fermentation in different reactor states

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PROCESS BIOCHEMISTRY 2001年第12期36卷 1225-1232页

作者： Xie, DM Liu, DH Liu, TZ Tsing Hua Univ Dept Chem Engn Inst Appl Chem Beijing 100084 Peoples R China Chinese Acad Sci Inst Chem Met State Key Lab Biochem Engn Beijing 100080 Peoples R China

A kinetic model of glycerol production by fermentation with the osmophilic yeast Candida krusei was studied firstly by analogies to published works. Considering that the glycerol produced competes with glucose, as a second carbon source for energy maintenance, mathematical models of glucose utilization and glycerol accumulation were modified further. By adjusting only two variable macrokinetic parameters, K-S and beta, the model simulations could fit experimental data well when the reactor was changed from Airlift Loop Reactor in different scale or airlift mode to Stirred Vessel. To avoid a significant reduction in glycerol production in the latter fermentation stage, the final condition of the fermentation, determined by the concentration ratio of glycerol to glucose, was also investigated in four different Reactor States. The kinetic models and simulation results can provide certain reference for scale up of glycerol production by fermentation. (C) 2001 Elsevier Science Ltd. All rights reserved.

关键词： kinetic model glycerol fermentation variable parameters reactor state Candida krusei

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