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Computer Aided Control Systems Design, 2004 IEEE International Symposium on

Date 2-4 Sept. 2004

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Displaying Results 1 - 25 of 85
  • The H2 control problem with internal stability

    Page(s): 107 - 114
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (754 KB) |  | HTML iconHTML  

    A solution of the H2 control problem is presented for linear systems described by rational transfer matrices. These rational matrices are not required to be proper and no assumption is made on the location of their poles and zeros. The control system is considered in the standard configuration, which includes the synthesis model of the plant and the controller. The H2 control problem consists of internally stabilizing the control system while minimizing the H2 norm of its transfer function. The notion of internal stability is based on input-output stability and means that the subsystems defined by any pair of input and output terminals within the control system all are input-output stable. The solution proceeds in three steps. Firstly, the set of all controllers that stabilize internally the control system is parametrized. Then the subset of the stabilizing controllers that achieve a finite value of the H2 norm of the system transfer function is described, also in parametric form. Finally, the optimal controller is obtained by selecting the parameter that minimizes the norm. The existence of these three sets of controllers is established in terms of the given data. The mathematical tool applied are doubly coprime, proper stable factorizations of rational matrices. Based on this description of the plant, two synthesis algorithms are derived: the primal and the dual one. The construction of the optimal controller requires two specific operations with proper stable rational matrices: inner-outer factorization and proper stable projection. The solution obtained is general in the sense that no assumptions on the plant are made other than those securing the outer factors to be square. View full abstract»

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  • Transient response shaping in H control by loose eigenstructure assignment technique

    Page(s): 225 - 230
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (674 KB) |  | HTML iconHTML  

    This paper proposes a design technique of state-feedback H control with transient response shaping. For direct transient response shaping, loose eigenstructure assignment technique is a effective technique. By using this technique, each of closed-loop eigenvalues (poles) and eigenvectors are assigned in the corresponding eigenvalue regions and eigenvector cones individually. The loose eigenstructure assignment problem is reduced to a rank-one LMI (linear matrix inequality) problem, and easily combined with H control by means of enhanced LMI characterization. View full abstract»

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  • An LMI approach to L2 gain analysis and control synthesis of switched systems

    Page(s): 350 - 355
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (642 KB) |  | HTML iconHTML  

    This paper investigates the L2 gain analysis and control synthesis of discrete-time switched systems under arbitrary switching by linear matrix inequality (LMI) approach together with switched Lyapunov function method. First, the existence of a switched Lyapunov function is proven to be equivalent to the feasibility of some LMIs. An upper bound of the L2 gain for switched systems can be computed by solving an eigenvalue problem (EVP). Then, we design a switched state feedback controller and a switched output feedback controller, respectively, guaranteeing that the corresponding closed-loop system is asymptotically stable with an L2 gain smaller than a fixed constant. LMI-based conditions for both cases are presented. Finally, two examples are given to illustrate our results. View full abstract»

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  • Robust H2 control of norm-bounded uncertain continuous-time system-an LMI approach

    Page(s): 243 - 248
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (615 KB) |  | HTML iconHTML  

    This paper considers robust H2 control problem of continuous-time systems with time-varying norm-bounded uncertainties. A necessary and sufficient condition for the analysis of robust H2 control is derived in the form of linear matrix inequalities (LMI). Using the analysis result, a state feedback controller and a dynamic output feedback controller are designed respectively so that the closed-loop uncertain system is quadratically stable and all its transfer matrices have H2-norm bounded by a prescribed value. With LMI manipulations, two necessary and sufficient conditions for the solvability of above design problems are addressed. View full abstract»

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  • 2004 IEEE International Symposium on Computer Aided Control Systems Design (IEEE Cat. No.04TH8770)

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  • [Breaker page]

    Page(s): 0_2
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  • 2004 IEEE International Symposium on Computer Aided Control Systems Design

    Page(s): 0_3
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  • Copyright page

    Page(s): 0_4
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  • Foreword

    Page(s): i - iii
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  • [Breaker page]

    Page(s): iv
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  • Conference organization

    Page(s): v - vii
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  • International Program Committee

    Page(s): viii
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  • National Program Committee

    Page(s): ix - x
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  • Table of contents

    Page(s): xi - xv
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  • [Breaker page]

    Page(s): xvi
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  • KYPD: a solver for semidefinite programs derived from the Kalman-Yakubovich-Popov lemma

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB) |  | HTML iconHTML  

    Semidefinite programs derived from the Kalman-Yakubovich-Popov lemma are quite common in control and signal processing applications. The programs are often of high dimension making them hard or impossible to solve with general-purpose solvers. KYPD is a customized solver for KYP-SDPs that utilizes the inherent structure of the optimization problem thus improving efficiency significantly View full abstract»

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  • Advanced axis control implementation within a virtual machine-tool environment

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (427 KB) |  | HTML iconHTML  

    Improvements in tracking performances are significant using generalized predictive control laws as machine tool feed drives control. Nevertheless, testing user-built control modules within a real CNC machine tool designed under a closed architecture is not straightforward. The creation of a virtual machining centre appears therefore as a solution to this problem. The paper presents developments of a three-axis machine tool simulator. It includes visualization facilities and allows relevant comparisons between different control strategies, proving to be a useful CACSD (computer aided control systems design) tool. Within this framework, the advantages of the predictive law can be easily underlined. Moreover, the advanced control structure fits the innovative demands of the open architecture View full abstract»

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  • Quantitative I/O-controllability assessment for uncertain plants

    Page(s): 13 - 18
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB) |  | HTML iconHTML  

    This paper deals with the calculation of the optimal control performance for linear time invariant plant models in the context of the screening of possible control structures. Compared to other approaches, e.g. the use of the relative gain array or other controllability indices, the proposed computation of the attainable control performance gives a quantitative assessment of a control structure without reference to a particular controller structure other than the assumption of linear control. In the time domain, control performance is measured in a least squares sense while constraints on manipulated and controlled variables can be included. The extension of the method presented here integrates the frequency domain condition for robust stability. Uncertainties are represented by the well known MDelta structure which renders the method generically applicable View full abstract»

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  • Sampled-data control toolbox: object-oriented software for sampled-data feedback control systems

    Page(s): 19 - 24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (325 KB) |  | HTML iconHTML  

    A MATLAB toolbox for analysis and design of sampled-data feedback control systems is developed. The package is an object-oriented library: several classes are defined for concerning systems and signals including sampled-data systems. Functions and operators are overloaded in the class definitions. Moreover, the implementation of analysis and design algorithms for sampled-data systems is also in an object-oriented fashion. Hence the implemented codes keeps high readability even for a general setting of sampled-data systems including multirate and delayed control/measurement cases, by using the class for systems with two point boundary conditions developed as a part of this library View full abstract»

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  • Enhanced LFR-toolbox for MATLAB

    Page(s): 25 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (378 KB) |  | HTML iconHTML  

    We describe recent developments and enhancements of the LFR-toolbox for MATLAB for building LFT-based uncertainty models. A major development is the new LFT-object definition supporting a large class of uncertainty descriptions: continuous- and discrete-time uncertain models, regular and singular parametric expressions, more general uncertainty blocks (nonlinear, time-varying, etc.). By associating names to uncertainty blocks the reusability of generated LFT-models and the user friendliness of manipulation of LFR-descriptions have been highly increased. Significant enhancements of the computational efficiency and of numerical accuracy have been achieved by employing efficient and numerically robust FORTRAN implementations of order reduction tools via Mex-function interfaces. The new enhancements in conjunction with improved symbolical preprocessing lead generally to a faster generation of LFT-models with significantly lower orders View full abstract»

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  • The development of finite element method package in CEMTool

    Page(s): 30 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    CEMTool is a command style design and analyzing package for scientific and technological algorithm and a matrix based computation language. In this paper, we present new FEM (finite element method) package in CEMTool environment. In contrast to the existing MATLAB PDE Toolbox, our proposed FEM package can deal with the combination of the reserved words. Also, we can control the mesh in a very effective way. With the introduction of new mesh generation algorithm and NDM (nested dissection method), our FEM package can guarantee the shorter computational time than MATLAB PDE Toolbox. In addition, using the advanced electromagnetics library of CEMTool FEM package, we can analyze the practical problems such as the motor field analysis. Consequently, with our new FEM package, we can overcome some disadvantages of the existing MATLAB PDE Toolbox View full abstract»

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  • Optimal hybrid control for switched affine systems under safety and liveness constraints

    Page(s): 35 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (434 KB) |  | HTML iconHTML  

    In this contribution, we propose a two-level hierarchical control strategy to solve the problem of minimising a cost function for a switched affine system under safety and liveness constraints. The constraints are handled on the lower level by a discrete supervisory controller designed using l-complete approximation. Its action can be represented as state invariants added to the plant model. In a bottom-up strategy, we can then synthesis a high-level controller, which computes a set of switching tables using the remaining degrees of freedom to optimise a quadratic performance index View full abstract»

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  • Control input synthesis for hybrid systems using informed search

    Page(s): 41 - 46
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (403 KB) |  | HTML iconHTML  

    We present a method for synthesizing a sequence of robust control inputs for a class of hybrid systems. Our goal is the generation of a control sequence that drives the system from a given initial state set to a pre-specified goal set without violating constraints on the system state, under the assumption that the hybrid system is exposed to bounded disturbances. We use a technique that combines dynamic programming and informed search. The control sequence generated by our synthesis procedure is guaranteed to meet safety requirements. An extension to nonlinear systems is presented and computational time is compared to a mixed-integer programming approach for computing an optimal but non-robust solution to the problem View full abstract»

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  • Formal approach to compute hybrid automata models for linear physical systems with switches

    Page(s): 47 - 52
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB) |  | HTML iconHTML  

    This paper considers the computation of a hybrid automaton that models the behaviour of a switching linear physical system using energy considerations. The system is represented in a compositional way with bond graphs that include switches. In a first step the switches are considered from a functional point of view. This allows to determine the locations that are associated to consistent configuration of switches, the continuous activities and the jumps. In a second step elementary models of switches are introduced and allow to determine the invariants and the guards of transitions. The approach is exemplified with a simple electronics circuit View full abstract»

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  • Algorithmic verification of logic controllers given as sequential function charts

    Page(s): 53 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB) |  | HTML iconHTML  

    The a-posteriori analysis of logic controllers can be a suitable means to detect design flaws if the controller was not developed by a synthesis algorithm that correctly considered all relevant requirements. This paper advocates the verification of logic controllers with a special focus on the following three issues: (a) the control code is given as a sequential function chart (SFC), a description language becoming increasingly popular for industrial controllers; (b) the cyclic operation mode of the hardware on which the controllers is implemented is taken into account; (c) specifications of the control logic that include timers and the real-time behavior of the controlled plant are considered. We propose an approach in which the SFC controller is first translated into a timed automaton using an algorithm that explores a special graph grammar. The automaton can then be composed with a timed automaton modeling the plant behavior, and model-checking of the composition reveals whether a given set of requirements is fulfilled. All steps of the procedure are illustrated for the example of a controlled evaporation system View full abstract»

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