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Hassan K. Khalil

Bio: Hassan K. Khalil is an academic researcher from Michigan State University. The author has contributed to research in topics: Nonlinear system & Nonlinear control. The author has an hindex of 57, co-authored 284 publications receiving 15992 citations. Previous affiliations of Hassan K. Khalil include Ford Motor Company & National Chiao Tung University.


Papers
More filters
Proceedings ArticleDOI
15 Jul 2009
TL;DR: Topology gradient and level set methods are coupled here with the finite element method for optimizing the shape of dielectric resonators included in microwave filters.
Abstract: The design of advanced components for space and terrestrial telecommunications requires both sophisticated design methodologies and manufacturing technologies for improving current component performances. In particular, determining the optimal shape and size of a component is a problem of primary importance for microwave engineers. In order to improve the classical microwave filters, shape and topology optimization methods can be utilized together with numerical modeling methods. Topology gradient and level set methods are coupled here with the finite element method for optimizing the shape of dielectric resonators included in microwave filters.

2 citations

Proceedings ArticleDOI
01 Dec 2009
TL;DR: This paper considers an alternate controller that shares with the controller of [1] the structure of high- gain partial state feedback and high-gain observer, but without internal model, and shows that when the controller and observer gains are high enough, the trajectories under the two controllers will be close to each other.
Abstract: In the paper [1], Serrani and Isidori design an output feedback controller that achieves semiglobal output regulation for a class of minimum phase nonlinear systems. The controller has three basic components: an internal model to ensure asymptotic regulation, a high-gain partial state feedback controller to stabilize the augmented system of the plant and the internal model, and a high-gain observer to implement the partial state feedback. In this paper we show a property of the transient performance of the controller of [1]. We consider an alternate controller that shares with the controller of [1] the structure of high-gain partial state feedback and high-gain observer, but without internal model. Such controller can only achieve practical regulation. We show that when the controller and observer gains are high enough, the trajectories under the two controllers will be close to each other. This property shows that the transient performance of the controller of [1] is not degraded by the inclusion of the internal model.

2 citations

Journal ArticleDOI
TL;DR: In this paper, a numerical model defined by a finite element method coupled with a topology gradient method is used for optimizing the shape of microwave components with respect to electrical specifications, which consists in minimizing a cost function with respect of the physical property of individual topological elements.
Abstract: A numerical model defined by a finite element method coupled with a topology gradient method is used for optimizing the shape of microwave components with respect to electrical specifications. The approach, which consists in minimizing a cost function with respect to the physical property of individual topological elements, which define the shape of the component, is first described. Regarding the given electrical specifications, the technique is applied for optimizing, respectively, in 2D, the distribution of metal upon the surface of a planar component and, in 3D, the distribution of dielectric material within a waveguide component. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2739–2743, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23751

2 citations

Proceedings ArticleDOI
02 Jun 1993
TL;DR: In this paper, the authors consider a single-input single-output (SISO) nonlinear system with a well defined normal form with asymptotically stable zero dynamics and design an output feedback controller which regulates the output to a constant reference in the presence of constant unkown input disturbances.
Abstract: We consider a single-input single-output (SISO) nonlinear system which has a well defined normal form with asymptotically stable zero dynamics. We allow the system's equation to depend on bounded uncertain parameters which do not change the relative degree. Our goal is to design an output feedback controller which regulates the output to a constant reference in the presence of constant unkown input disturbances. The disturbance vector fields satisfy geometric conditions which ensure that the system is transformable into the so called disturbance-strict-feedback form. The integral of the regulation error is augmented to the system equation and a robust output feedback controller is designed to bring the state of the closed-loop system to a positively invariant set. Once inside this set, the trajectories approach a unique equilibrium point at which the regulation error is zero. We give regional as well as semi-global results.

2 citations


Cited by
More filters
Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Book
01 Jan 1994
TL;DR: In this paper, the authors present a brief history of LMIs in control theory and discuss some of the standard problems involved in LMIs, such as linear matrix inequalities, linear differential inequalities, and matrix problems with analytic solutions.
Abstract: Preface 1. Introduction Overview A Brief History of LMIs in Control Theory Notes on the Style of the Book Origin of the Book 2. Some Standard Problems Involving LMIs. Linear Matrix Inequalities Some Standard Problems Ellipsoid Algorithm Interior-Point Methods Strict and Nonstrict LMIs Miscellaneous Results on Matrix Inequalities Some LMI Problems with Analytic Solutions 3. Some Matrix Problems. Minimizing Condition Number by Scaling Minimizing Condition Number of a Positive-Definite Matrix Minimizing Norm by Scaling Rescaling a Matrix Positive-Definite Matrix Completion Problems Quadratic Approximation of a Polytopic Norm Ellipsoidal Approximation 4. Linear Differential Inclusions. Differential Inclusions Some Specific LDIs Nonlinear System Analysis via LDIs 5. Analysis of LDIs: State Properties. Quadratic Stability Invariant Ellipsoids 6. Analysis of LDIs: Input/Output Properties. Input-to-State Properties State-to-Output Properties Input-to-Output Properties 7. State-Feedback Synthesis for LDIs. Static State-Feedback Controllers State Properties Input-to-State Properties State-to-Output Properties Input-to-Output Properties Observer-Based Controllers for Nonlinear Systems 8. Lure and Multiplier Methods. Analysis of Lure Systems Integral Quadratic Constraints Multipliers for Systems with Unknown Parameters 9. Systems with Multiplicative Noise. Analysis of Systems with Multiplicative Noise State-Feedback Synthesis 10. Miscellaneous Problems. Optimization over an Affine Family of Linear Systems Analysis of Systems with LTI Perturbations Positive Orthant Stabilizability Linear Systems with Delays Interpolation Problems The Inverse Problem of Optimal Control System Realization Problems Multi-Criterion LQG Nonconvex Multi-Criterion Quadratic Problems Notation List of Acronyms Bibliography Index.

11,085 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a state-of-the-art survey of ANN applications in forecasting and provide a synthesis of published research in this area, insights on ANN modeling issues, and future research directions.

3,680 citations

Journal ArticleDOI
Arie Levant1
TL;DR: In this article, the authors proposed arbitrary-order robust exact differentiators with finite-time convergence, which can be used to keep accurate a given constraint and feature theoretically-infinite-frequency switching.
Abstract: Being a motion on a discontinuity set of a dynamic system, sliding mode is used to keep accurately a given constraint and features theoretically-infinite-frequency switching. Standard sliding modes provide for finite-time convergence, precise keeping of the constraint and robustness with respect to internal and external disturbances. Yet the relative degree of the constraint has to be 1 and a dangerous chattering effect is possible. Higher-order sliding modes preserve or generalize the main properties of the standard sliding mode and remove the above restrictions. r-Sliding mode realization provides for up to the rth order of sliding precision with respect to the sampling interval compared with the first order of the standard sliding mode. Such controllers require higher-order real-time derivatives of the outputs to be available. The lacking information is achieved by means of proposed arbitrary-order robust exact differentiators with finite-time convergence. These differentiators feature optimal asymptot...

2,954 citations