Design Procedure (design + procedure)

Distribution by Scientific Domains
Distribution within Engineering

Kinds of Design Procedure

  • control design procedure
  • proposed design procedure


  • Selected Abstracts


    Alternativen zur vereinfachten Bemessung von Einzelstützen?

    BETON- UND STAHLBETONBAU, Issue 6 2006
    Ulrich Quast Univ.-Prof.
    Es werden die vereinfachte Berechnung von Einzeldruckgliedern nach Theorie 2. Ordnung mit Ersatzbiegesteifigkeiten nach Eurocode 2 und die Berechnung als erweiterte Querschnittsbemessung am Beispiel einer schlanken zweiachsig ausmittig beanspruchten Stütze behandelt. Alternative simplified Design Procedures for isolated Columns? The simplified 2nd order analysis for isolated compression members with nominal stiffness as in Eurocode 2 and the transformation of the non-linear 2nd order analysis to a modified cross section design are dealt by example of a slender cantilever column with biaxial bending. [source]


    A program for the design of linear time invariant control systems: CDMCAD

    COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2004
    M. Koksal
    Abstract Coefficient Diagram Method (CDM) is a new method proposed for the analysis and design of linear time-invariant control systems. The control system design by this method results with satisfactory stability, time response and robustness properties compatible with, and in most cases better than, the ones obtained by the other present design methods. In this study, the design procedure described in the literature for CDM is improved so that a systematic and easy tool with understandable sufficient detail is presented. A visual toolbox, which can be used efficiently both for education and research, is obtained based on the procedure presented by using MATLAB. © 2004 Wiley Periodicals, Inc. Comput Appl Eng Educ 12: 165,174, 2004; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20011 [source]


    Three-dimensional vibration control of high-tech facilities against earthquakes and microvibration using hybrid platform

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2010
    Xiao-Jian Hong
    Abstract High-tech equipments engaged in the production of ultra-precision products have very stringent vibration criteria for their functionality in normal operation conditions and their safety during an earthquake. Most previous investigations were based on simplified planar models of building structures, despite the fact that real ground motions and structures are always three-dimensional. This paper hence presents a three-dimensional analytical study of a hybrid platform on which high-tech equipments are mounted for their vibration mitigation. The design methodology of the hybrid platform proposed in this study is based on dual-level performance objectives for high-tech equipments: safety against seismic hazard and functionality against traffic-induced microvibration. The passive devices (represented by springs and viscous dampers) and the active actuators are designed, respectively, to meet vibration criteria corresponding to safety level and functionality level. A prototype three-story building with high-tech equipments installed on the second floor is selected in the case study to evaluate the effectiveness of the hybrid platform. The optimal location of the platform on the second building floor is determined during the design procedure in terms of the minimal H2 cost function of absolute velocity response. The simulation of the coupled actuator-platform-building system subjected to three-dimensional ground motions indicates that the optimally designed hybrid platform can well achieve the dual target performance and effectively mitigate vibration at both ground motion levels. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Design of passive systems for control of inelastic structures

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2009
    Gian Paolo Cimellaro
    Abstract A design strategy for control of buildings experiencing inelastic deformations during seismic response is formulated. The strategy is using weakened, and/or softened, elements in a structural system while adding passive energy dissipation devices (e.g. viscous fluid devices, etc.) in order to control simultaneously accelerations and deformations response during seismic events. A design methodology is developed to determine the locations and the magnitude of weakening and/or softening of structural elements and the added damping while insuring structural stability. A two-stage design procedure is suggested: (i) first using a nonlinear active control algorithm, to determine the new structural parameters while insuring stability, then (ii) determine the properties of equivalent structural parameters of passive system, which can be implemented by removing or weakening some structural elements, or connections, and by addition of energy dissipation systems. Passive dampers and weakened elements are designed using an optimization algorithm to obtain a response as close as possible to an actively controlled system. A case study of a five-story building subjected to El Centro ground motion, as well as to an ensemble of simulated ground motions, is presented to illustrate the procedure. The results show that following the design strategy, a control of both peak inter-story drifts and total accelerations can be obtained. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Pure aluminium shear panels as dissipative devices in moment-resisting steel frames

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2007
    G. De Matteis
    Abstract The use of energy dissipation systems for the seismic control of steel structures represents a valid alternative to conventional seismic design methods. The seismic devices currently employed are mostly based on the metallic yielding technology due to the large feasibility and efficiency they can provide. Within this context, in the current paper an innovative solution based on the adoption of low-yield-strength pure aluminium shear panels (SPs) for seismic protection of steel moment-resisting frames is proposed and investigated. In order to prove the effectiveness of the system, a wide numerical study based on both static and dynamic non-linear analyses has been carried out, considering a number of different frame-to-shear panel combinations, aiming at assessing the effect of the main influential parameters on the seismic response of the structure. The obtained results show that the contribution provided by aluminium SPs is rather significant, allowing a remarkable improvement of the seismic performance of the structure in terms of stiffness, strength and ductility, with the possibility to strongly limit the damage occurring in the members of moment-resisting frames. In particular, it is clearly emphasized that the stiffening effect provided by SPs allows a more rational design procedure to be adopted, since the serviceability limit state check does not lead to unavoidable and uneconomical increase of the size of main structural members. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Development and validation of a metallic haunch seismic retrofit solution for existing under-designed RC frame buildings

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2006
    Stefano Pampanin
    Abstract The feasibility and efficiency of a seismic retrofit solution for existing reinforced concrete frame systems, designed before the introduction of modern seismic-oriented design codes in the mid 1970s, is conceptually presented and experimentally investigated. A diagonal metallic haunch system is introduced at the beam,column connections to protect the joint panel zone from extensive damage and brittle shear mechanisms, while inverting the hierarchy of strength within the beam,column subassemblies and forming a plastic hinge in the beam. A complete step-by-step design procedure is suggested for the proposed retrofit strategy to achieve the desired reversal of strength hierarchy. Analytical formulations of the internal force flow at the beam,column-joint level are derived for the retrofitted joints. The study is particularly focused on exterior beam,column joints, since it is recognized that they are the most vulnerable, due to their lack of a reliable joint shear transfer mechanism. Results from an experimental program carried out to validate the concept and the design procedure are also presented. The program consisted of quasi-static cyclic tests on four exterior, , scaled, beam,column joint subassemblies, typical of pre-1970 construction practice using plain round bars with end-hooks, with limited joint transverse reinforcement and detailed without capacity design considerations. The first (control specimen) emulated the as-built connection while the three others incorporated the proposed retrofitted configurations. The experimental results demonstrated the effectiveness of the proposed solution for upgrading non-seismically designed RC frames and also confirmed the applicability of the proposed design procedure and of the analytical derivations. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Seismic design of bridges accounting for spatial variability of ground motion

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4-5 2005
    A. Lupoi
    Abstract The effects of the spatial variability of the ground motion on the response of bridge structures are investigated in this study. Following a well-established convention, the phenomenon is represented as the combined effect of three causes: the loss of coherence of the motion with distance, the wave-passage, and the local site conditions. Since the nature and amount of non-synchronism vary within ample limits a statistical approach is adopted. A parametric study is carried out on a representative set of bridges subjected to carefully selected combinations of the factors inducing spatial variability. The investigation has shown that the phenomenon affects the response considerably and, hence, the level of protection of these structures. It is observed that for all bridge types considered, the ductility demands at the base of the piers in the presence of spatial variability increase in the majority of cases. Further, for a given bridge type, the probabilities of failure vary by more than one order of magnitude depending on the combination of the parameters. Attention has been focused on a parameter representing the ratio between the maximum curvature ductility demand and the same quantity for the case of fully synchronous motion. This parameter has been used to correct the conventional synchronous design procedure by increasing the available ductility. The re-analysis of all the cases with a modified ductility capacity shows that the procedure is effective in reducing the fragilities to the values corresponding to synchronous input. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Improved design of sliding mode control for civil structures with saturation problem

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 11 2004
    Sang-Hyun Lee
    Abstract A systematic and improved design procedure for sliding mode control (SMC) of seismically excited civil structures with saturation problem is provided in this paper. In order to restrict the control force to a certain level, a procedure for determining the upper limits of the control forces for single or multiple control units is proposed based on the design response spectrum of external loads. Further, an efficient procedure using the LQR method for determining sliding surfaces appropriate for different controller types is provided through the parametric evaluation of the dynamic characteristics of sliding surfaces in terms of SMC controller performance. Finally, a systematic design procedure for SMC required to achieve a given performance level is provided and its effectiveness is verified by applying it to multi-degree-of-freedom (MDOF) systems. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    A displacement-based seismic design procedure for RC buildings and comparison with EC8

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2001
    T. B. Panagiotakos
    Abstract A procedure for displacement-based seismic design (DBD) of reinforced concrete buildings is described and applied to a 4-storey test structure. The essential elements of the design procedure are: (a) proportioning of members for gravity loads; (b) estimation of peak inelastic member deformation demands in the so-designed structure due to the design (,life-safety') earthquake; (c) revision of reinforcement and final detailing of members to meet these inelastic deformation demands; (d) capacity design of members and joints in shear. Additional but non-essential steps between (a) and (b) are: (i) proportioning of members for the ULS against lateral loads, such as wind or a serviceability (,immediate occupancy') earthquake; and (ii) capacity design of columns in flexure at joints. Inelastic deformation demands in step (b) are estimated from an elastic analysis using secant-to-yield member stiffnesses. Empirical expressions for the deformation capacity of RC elements are used for the final proportioning of elements to meet the inelastic deformation demands. The procedure is applied to one side of a 4-storey test structure that includes a coupled wall and a two-bay frame. The other side is designed and detailed according to Eurocode 8. Major differences result in the reinforcement of the two sides, with significant savings on the DBD-side. Pre-test calculations show no major difference in the seismic performance of the two sides of the test structure. Copyright © 2001 John Wiley & Sons, Ltd. [source]


    Development and application of the human intestinal tract chip, a phylogenetic microarray: analysis of universally conserved phylotypes in the abundant microbiota of young and elderly adults

    ENVIRONMENTAL MICROBIOLOGY, Issue 7 2009
    -Stojanovi, Mirjana Rajili
    Summary In this paper we present the in silico assessment of the diversity of variable regions of the small subunit ribosomal RNA (SSU rRNA) gene based on an ecosystem-specific curated database, describe a probe design procedure based on two hypervariable regions with minimal redundancy and test the potential of such probe design strategy for the design of a flexible microarray platform. This resulted in the development and application of a phylogenetic microarray for studying the human gastrointestinal microbiota , referred as the human intestinal tract chip (HITChip). Over 4800 dedicated tiling oligonucleotide probes were designed based on two hypervariable regions of the SSU rRNA gene of 1140 unique microbial phylotypes (< 98% identity) following analysis of over 16 000 human intestinal SSU rRNA sequences. These HITChip probes were hybridized to a diverse set of human intestinal samples and SSU rRNA clones to validate its fingerprinting and quantification potential. Excellent reproducibility (median Pearson's correlation of 0.99) was obtained following hybridization with T7 polymerase transcripts generated in vitro from SSU rRNA gene amplicons. A linear dose,response was observed with artificial mixtures of 40 different representative amplicons with relative abundances as low as 0.1% of total microbiota. Analysis of three consecutively collected faecal samples from ten individuals (five young and five elderly adults) revealed temporal dynamics and confirmed that the adult intestinal microbiota is an individual-specific and relatively stable ecosystem. Further analysis of the stable part allowed for the identification of a universal microbiota core at the approximate genus level (90% sequence similarity). This core consists of members of Actinobacteria, Bacteroidetes and Firmicutes. Used as a phylogenetic fingerprinting tool with the possibility for relative quantification, the HITChip has the potential to bridge the gaps in our knowledge in the quantitative and qualitative description of the human gastrointestinal microbiota composition. [source]


    Design of change detection algorithms based on the generalized likelihood ratio test

    ENVIRONMETRICS, Issue 8 2001
    Giovanna Capizzi
    Abstract A design procedure for detecting additive changes in a state-space model is proposed. Since the mean of the observations after the change is unknown, detection algorithms based on the generalized likelihood ratio test, GLR, and on window-limited type GLR, are considered. As Lai (1995) pointed out, it is very difficult to find a satisfactory choice of both window size and threshold for these change detection algorithms. The basic idea of this article is to estimate, through the stochastic approximation of Robbins and Monro, the threshold value which satisfies a constraint on the mean between false alarms, for a specified window size. A convenient stopping rule, based on the first passage time of an F -statistic below a fixed boundary, is used to terminate the iterative approximation. Then, the window size which produces the most desirable out-of-control ARL, for a fixed value of the in-control ARL, can be selected. These change detection algorithms are applied to detect biases on the measurements of ozone, recorded from one monitoring site of Bologna (Italy). Comparisons of the ARL profiles reveal that the full-GLR scheme provides much more protection than the window-limited GLR schemes against small shifts in the process, but the modified window-limited GLR provides more protection against large shifts. Copyright © 2001 John Wiley & Sons, Ltd. [source]


    Design and comparison of different flux-switch synchronous machines for an aircraft oil breather application

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2005
    Yacine Amara
    This paper presents a design procedure of a flux,switch synchronous machine for an aircraft oil breather application. This work is part of a European project called ,Power Optimised Aircraft'. The aim of this project is to replace some mechanical equipment by electromechanical devices to improve performance and reduce power consumption. The structure under study was developed at SATIE laboratory and it is based on the flux-switch principle. The permanent magnets are located in the stator, and the rotor is entirely passive. The study described in this paper is limited to the electromagnetic design. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Parameter estimation accuracy analysis for induction motors

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2005
    E. Laroche
    Abstract Various analytical dynamic models of induction machines, some of which take magnetic saturation and iron loss into account, are available in the literature. When parameter estimation is required, models must not only be theoretically identifiable but allow for accurate parameter estimation as well. This paper presents a comparison of parameter estimation accuracies obtained using different models and sets of measurements in the case of steady-state sinusoidal measurements. An explicit expression of estimation error is established and evaluated with respect to several measurement and modelling errors. This study will show that certain models are better suited for identification purposes than others and that certain sensors are bound to be more accurate than others. Lastly, an optimal experimental design procedure is implemented in order to derive an improved measurement set that leads to reduced estimation errors. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Optimal piecewise linear radial compression function for Laplacian source

    EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 8 2008
    Zoran H. Peri
    In order to achieve a quantisation technique that has low implementation complexity and performance arbitrarily close to that of Laplacian source optimal vector quantisation, a model of optimal geometric piecewise uniform cubic lattice vector quantiser will be proposed. It will be shown that the presented design procedure is not only much easier for realisation than the procedure of optimal vector quantiser design, but also gives the signal to quantisation noise ratio which in some cases differs from that of the optimal vector quantisation for 0.05,dB and less. It will also be demonstrated that the optimal geometric piecewise uniform vector quantiser model can be described with the optimal piecewise linear radial compression function. Further, since the optimal geometric piecewise uniform lattice vector quantisation in the case of large enough subregions number has performances identical to those of optimal vector quantisation, the optimal nonlinear radial compression function for Laplacian source will also be derived. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Integrated layout design of multi-component system

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2009
    Jihong Zhu
    Abstract A new integrated layout optimization method is proposed here for the design of multi-component systems. By introducing movable components into the design domain, the components layout and the supporting structural topology are optimized simultaneously. The developed design procedure mainly consists of three parts: (i) Introduction of non-overlap constraints between components. The finite circle method (FCM) is used to avoid the components overlaps and also overlaps between components and the design domain boundaries. (ii) Layout optimization of the components and supporting structure. Locations and orientations of the components are assumed as geometrical design variables for the optimal placement while topology design variables of the supporting structure are defined by the density points. Meanwhile, embedded meshing techniques are developed to take into account the finite element mesh change caused by the component movements. (iii) Consistent material interpolation scheme between element stiffness and inertial load. The commonly used solid isotropic material with penalization model is improved to avoid the singularity of localized deformation in the presence of design dependent loading when the element stiffness and the involved inertial load are weakened by the element material removal. Finally, to validate the proposed design procedure, a variety of multi-component system layout design problems are tested and solved on account of inertia loads and gravity center position constraint. Solutions are compared with traditional topology designs without component. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Optimal solid shell element for large deformable composite structures with piezoelectric layers and active vibration control

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 15 2005
    X. G. Tan
    Abstract In this paper, we present an optimal low-order accurate piezoelectric solid-shell element formulation to model active composite shell structures that can undergo large deformation and large overall motion. This element has only displacement and electric degrees of freedom (dofs), with no rotational dofs, and an optimal number of enhancing assumed strain (EAS) parameters to pass the patch tests (both membrane and out-of-plane bending). The combination of the present optimal piezoelectric solid-shell element and the optimal solid-shell element previously developed allows for efficient and accurate analyses of large deformable composite multilayer shell structures with piezoelectric layers. To make the 3-D analysis of active composite shells containing discrete piezoelectric sensors and actuators even more efficient, the composite solid-shell element is further developed here. Based on the mixed Fraeijs de Veubeke,Hu,Washizu (FHW) variational principle, the in-plane and out-of-plane bending behaviours are improved via a new and efficient enhancement of the strain tensor. Shear-locking and curvature thickness locking are resolved effectively by using the assumed natural strain (ANS) method. We also present an optimal-control design for vibration suppression of a large deformable structure based on the general finite element approach. The linear-quadratic regulator control scheme with output feedback is used as a control law on the basis of the state space model of the system. Numerical examples involving static analyses and dynamic analyses of active shell structures having a large range of element aspect ratios are presented. Active vibration control of a composite multilayer shell with distributed piezoelectric sensors and actuators is performed to test the present element and the control design procedure. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Iterative adaptive robust control of multivariable CD processes

    INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2010
    Fazel Farahmand
    Abstract In this paper we present a novel adaptive robust control approach to the multivariable cross-directional (CD) process of continuous web manufacturing. The common assumption of spatial frequency decomposition (SFD) is used to allow the process analysis in terms of a family of single-input single-output (SISO) transfer functions across the spatial frequencies. We then apply discretized Windsurfing adaptive robust control to each individual separated spatial frequency, starting with a stable initial model and a robust stabilizing controller at each spatial frequency. This approach allows the 2D bandwidth of the closed-loop system to be increased progressively at each spatial frequency through an iterative relevant system identification and control design procedure. The method deals with both model uncertainty and measurement noise issues. Simulation results are given to illustrate the performance of the applied method. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Neural network-based adaptive attitude tracking control for flexible spacecraft with unknown high-frequency gain

    INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 6 2010
    Qinglei Hu
    Abstract Adaptive control design using neural networks (a) is investigated for attitude tracking and vibration stabilization of a flexible spacecraft, which is operated at highly nonlinear dynamic regimes. The spacecraft considered consists of a rigid body and two flexible appendages, and it is assumed that the system parameters are unknown and the truncated model of the spacecraft has finite but arbitrary dimension as well, for the purpose of design. Based on this nonlinear model, the derivation of an adaptive control law using neural networks (NNs) is treated, when the dynamics of unstructured and state-dependent nonlinear function are completely unknown. A radial basis function network that is used here for synthesizing the controller and adaptive mechanisms is derived for adjusting the parameters of the network and estimating the unknown parameters. In this derivation, the Nussbaum gain technique is also employed to relax the sign assumption for the high-frequency gain for the neural adaptive control. Moreover, systematic design procedure is developed for the synthesis of adaptive NN tracking control with L2 -gain performance. The resulting closed-loop system is proven to be globally stable by Lyapunov's theory and the effect of the external disturbances and elastic vibrations on the tracking error can be attenuated to the prescribed level by appropriately choosing the design parameters. Numerical simulations are performed to show that attitude tracking control and vibration suppression are accomplished in spite of the presence of disturbance torque/parameter uncertainty. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    A combined iterative scheme for identification and control redesigns

    INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2004
    Paresh Date
    Abstract This work proposes a unified algorithm for identification and control. Frequency domain data of the plant is weighted to satisfy the given performance specifications. A model is then identified from this weighted frequency domain data and a controller is synthesised using the ,, loopshaping design procedure. The cost function used in the identification stage essentially minimizes a tight upper bound on the difference between the achieved and the designed performance in the sense of the ,, loopshaping design paradigm. Given a model, a method is also suggested to re-adjust model and weighting transfer functions to reduce further the worst case chordal distance between the weighted true plant and the model. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Modeling and synthesis of the interdigital/stub composite right/left-handed artificial transmission line

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2009
    R. Siragusa
    Abstract An efficient design procedure, including both analysis and synthesis, is proposed for Composite Right/Left Handed (CRLH) interdigital/stub structures. Improved models are developed for both the interdigital capacitor and the shorted stub inductor including its ground via hole. Subsequent optimal formulas are recommended to model these components with their parasitic effects. The models and formulas are verified by both full-wave and experimental results. A CAD program with a friendly GUI, available online, is provided and its operation is described in details. This program allows a very fast design of the CRLH structure, and its synthesis parameters are proven very accurate without any full-wave optimization. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. [source]


    Design and optimization of multi-band Wilkinson power divider

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2008
    Nihad Dib
    Abstract In this paper, a general and easy procedure for designing the symmetrical Wilkinson power divider that achieves equal-power split at N arbitrary frequencies is introduced. Each quarter-wave branch in the conventional Wilkinson divider is replaced by N sections of transmission lines, and the isolation between the output ports is achieved by using N resistors. The design parameters are the characteristic impedances and lengths of the N transmission line sections, and the N isolation resistors. The even,odd modes of analysis are used to derive the design equations. Closed-form expressions, which are suitable for CAD purposes, are derived for the dual-band divider. For N , 3, closed-form expressions are not available, and therefore, the powerful particle swarm optimization method is used to obtain the design parameters. Examples of the dual-, triple-, and quad-band dividers are presented to validate the proposed design procedure, and the results are compared, wherever possible, with published results using other methods. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source]


    Design of miniature wideband interdigital filters

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2007
    Neil Thomson
    Abstract In this paper a practical design procedure is suggested for designing wideband miniature interdigital filters. The proposed design approach is based on a concept of parameter mapping between two wideband filters, i.e. a conventional interdigital filter with uniform impedance resonators (UIR) and a desired miniature interdigital filter using stepped impedance resonators (SIR), allowing filter designers to deploy traditional designs with powerful electromagnetic (EM) simulators. For demonstration, a five-pole SIR interdigital filter with a fractional bandwidth (FBW) of 25% has been designed, fabricated, and tested. The demonstrator shows an excellent performance, which matches well to that of its conventional counterpart so as to validate the proposed design procedure. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007. [source]


    Analysis of microwave components and circuits using the iterative method

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2004
    A. Mami
    Abstract This article presents an efficient implementation of an iterative method that includes a fast-mode transformation (FMT). The method has the advantages of simplicity and not involving basis functions and inversion of matrices, as used in other calculation methods. Therefore, this approach has the potential to be capable of analysing larger bodies than other classical techniques. An implementation of the iterative calculation is shown for the extraction of S parameters of microwave components and antennas. The good agreement between the simulation results and experimental published data justifies the design procedure and validates the present analysis approach. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 404,414, 2004. [source]


    A compact band-pass filter using multi-element resonators

    INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 6 2003
    Kenneth V. Puglia
    Abstract A compact, band-pass filter utilizing multi-element resonators, structured from sections of distributed transmission lines, is presented. A band-pass filter design procedure is established that emphasizes CAD techniques to characterize the individual resonators and to determine the resonator coupling values required for a specified pass-band response. Detailed band-pass filter design examples are illustrated and simulation results are employed to validate the design procedure. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 447,458, 2003. [source]


    Robust control of T-S fuzzy systems with time-varying delay using new approach

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2010
    Hamdi Gassara
    Abstract This paper aims to design a controller to robustly stabilize uncertain nonlinear systems with time-varying delay and norm bounded uncertainties via Takagi,Sugeno (T-S) fuzzy model. The stabilization conditions are given in the form of linear matrix inequalities using a single Lyapunov,Krasovskii functional (LKF) combining the introduction of some relaxation matrices and only one tuning parameter. In comparison with the existing techniques in the literature, the proposed approach has two major advantages. The first is the reduction of computational complexity when the number of IF-THEN rules, r, is big. The second concerns the conservatism reduction. Several examples are given to show the effectiveness and the merits of the design procedure. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    A hybrid controller design for bi-axial inverted pendulum system

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2009
    Long-Hong Chang
    Abstract This study presents the use of Tustin's friction model and a disturbance observer (DOB) to improve the steady-state error (SSE) of a bi-axial inverted pendulum,cart system (IPCS). Furthermore, a hybrid controller contains a feedback linearization control for pendulum angle in the region of 3,12° to enlarge the angle of operation and an H, control using loop shaping design procedure (LSDP) for cart position and pendulum angle in the region of 0,3° to stabilize the IPCS, respectively. Experimental results reveal that the pendulum maximum angle of operation is improved from 7 to 12°; the SSE of the angle of the pendulum is reduced from 0.85 to 0.1°, and the SSE of the position of the cart is reduced from 10 to 1.4,mm. Experimental results are illustrated and films are provided at the web site http://hinfinity.myweb.hinet.net to show the effectiveness and robustness of the hybrid controller with Tustin's friction model and DOB compensation. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Explicit constructions of global stabilization and nonlinear H, control laws for a class of nonminimum phase nonlinear multivariable systems

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2008
    Weiyao Lan
    Abstract This paper investigates a global stabilization problem and a nonlinear H, control problem for a class of nonminimum phase nonlinear multivariable systems. To avoid the complicated recursive design procedure, an asymptotic time-scale and eigenstructure assignment method is adopted to construct the control laws for the stabilization problem and the nonlinear H, control problem. A sufficient solvability condition is established onthe unstable zero dynamics of the system for global stabilization problem and nonlinear H, control problem, respectively. Moreover, based on the sufficient solvability condition, an upper bound of the achievable L2 -gain is estimated for the nonlinear H, control problem. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Global stabilization of uncertain stochastic nonlinear time-delay systems by output feedback

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 9 2008
    Peng Cui
    Abstract Constructive control techniques have been proposed for controlling strict feedback (lower triangular form) stochastic nonlinear systems with a time-varying time delay in the state. The uncertain nonlinearities are assumed to be bounded by polynomial functions of the outputs multiplied by unmeasured states or delayed states. The delay-independent output feedback controller making the closed-loop system globally asymptotically stable is explicitly constructed by using a linear dynamic high-gain observer in combination with a linear dynamic high-gain controller. A simulation example is given to demonstrate the effectiveness of the proposed design procedure. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Robust tracking control for a class of MIMO nonlinear systems with measurable output feedback

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2008
    Ya-Jun Pan
    Abstract This paper proposes a robust output feedback controller for a class of nonlinear systems to track a desired trajectory. Our main goal is to ensure the global input-to-state stability (ISS) property of the tracking error nonlinear dynamics with respect to the unknown structural system uncertainties and external disturbances. Our approach consists of constructing a nonlinear observer to reconstruct the unavailable states, and then designing a discontinuous controller using a back-stepping like design procedure to ensure the ISS property. The observer design is realized through state transformation and there is only one parameter to be determined. Through solving a Hamilton,Jacoby inequality, the nonlinear control law for the first subsystem specifies a nonlinear switching surface. By virtue of nonlinear control for the first subsystem, the resulting sliding manifold in the sliding phase possesses the desired ISS property and to certain extent the optimality. Associated with the new switching surface, the sliding mode control is applied to the second subsystem to accomplish the tracking task. As a result, the tracking error is bounded and the ISS property of the whole system can be ensured while the internal stability is also achieved. Finally, an example is presented to show the effectiveness of the proposed scheme. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    A hybrid model predictive control approach to the direct torque control problem of induction motors

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 17 2007
    Georgios Papafotiou
    Abstract Direct torque control (DTC) is a state-of-the-art control methodology for electric motor drives which features favourable control performance and implementation properties. In DTC, the core of the control system is the inverter switching table, and any efforts to enhance the system's performance aim at improving its design. This issue is addressed in this paper, where we propose a new design procedure for the DTC problem. The DTC drive, comprising a two- or three-level dc-link inverter driving a three-phase induction motor, is modelled in the hybrid mixed logical dynamical (MLD) framework, and a constrained finite-time optimal control problem is set up and solved over a receding horizon using model predictive control (MPC). Simulation results are provided and compared to the current industrial standard demonstrating the potential for notable performance improvements. Copyright © 2007 John Wiley & Sons, Ltd. [source]