• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.389-395
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• 2007

In this paper, we consider the robust non-fragile $H_{\infty}$ output feedback controller design method for uncertain descriptor systems with feedback and observer gain variations. The existence condition of observer-based robust and non-fragile $H_{\infty}$ output feedback controller and the controller design method are Presented on the basis of linear matrix inequality approach. The proposed robust non-fragile $H_{\infty}$ output feedback controller guarantees asymptotic stability, non-fragility, $H_{\infty}$ norm bound within a prescribed level in spite of disturbance, parameter uncertainty, and feedback/observer gain variations.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.2
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• pp.151-156
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• 1998

This paper presents an $H_{\infty)$ output feedback controller design method for linear systems with delayed state, delayed control input, and delayed masurement output. Using a Lyapunov functional, the stability for delayed systems is discussed independently of delays. Also, sufficient condition for the existence of $H_{\infty)$ controllers of any order is given in terms of three linear matrix inequalities(LMIs). Based on positive definite solutions of their LMIs, we briefly explain the way to construct $H_{\infty)$ controller, which stabilizes time-delay systems independently of delays and guarantees an $H_{\infty)$norm bound.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.3
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• pp.13-18
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• 2005

This paper presents a design of a multi-objective $H_2/H_{\infty}$ controller of an inverted pendulum with polytopic model by the stabilizing regulator and tracking performances. Multi-objective controllers are designed for polytopic models by the LMI design technique with convex algorithms. It is observed that the inverted pendulum controlled by any controller designed for each polytopic model is stably restored to the vertical angle position for initial values of larger tilt angles.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.6
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• pp.735-746
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• 1999

We design the robust and inherently fault tolerant decetralized$$H^infty$$ filter for the multisensor state estimation problem when there are insufficient priori informations on the statistical properties of external disturbances. For developing the proposed algorithm, an alternative form of suboptimal$$H^infty$$ filter equations are formulated by applying an alternative form of Kalman filter equations to the indefinite inner product space state model of suboptimal$$H^infty$$ filtering problems. The decentralized$$H^infty$$ filter that consists of local and central fusion filters can be designed effciently using the proposed alternative$$H^infty$$ filiter gain equations. The proposed decentralized$$H^infty$$ filter is robust against un-known external disturbances since it bounds the maximum energy gain from the external disturbances to the estimation errors under the prescribed level$$r^2$$ in both local and central fusion filters and is also fault tolerant due to its inherent redundancy. In addition, the central fusion equations between the global and local data can reduce the unnecessary calculation burden effectively. Computer simulations are made to ceritfy the robustness and fault tolerance of the proposed algorithm.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1297-1300
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• 2005

In this study the gradient method is used to design a mixed $H_2/H_{\infty}$ controller. It is verified by an example that is BTT missile. We expect through the results of this study that gradient method can be easily applied to diverse optimization problems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.401-405
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• 1996

A new method of nonlinear robust controller synthesis is introduced which is an extension of linear mixed $H_2/H_{\infty}$ control. This method guarantees robust stability fur hard nonlinearity and uncertainty of the plant. The method is applied to the control of a flexible link of robot with Coulomb friction. Simulation shows good performances with respect to the response and the robustness.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.2
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• pp.214-219
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• 2010

This paper deals with a nonlinear fuzzy $H_{\infty}$ filter design for SOC(state of charge) estimation in Lithium polymer battery. The dynamic equation of the battery cell is modeled as a T-S fuzzy system and the filter is designed via solutions of linear matrix inequalities. In order to illustrate the performance of the designed filter, a computer simulation is performed using the experimental data with the UDDS(urban dynamometer driving schedule) current profile.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.102-109
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• 1997

A two-degree-of freedom (TDF) $H_{\infty}$controller for a seeker scan loop is presented for the purpose of improving scanning performances. The perturbed plant model is characterized via the normalized coprime factorization. The TDF $H_{\infty}$controller is designed based on the loop shaping design procedure and model matching approach, and its performances are evaluated and compared with those of a previous work. It is demonstrated that the proposed TDF $H_{\infty}$controller is more effective to the control of the seeker scan loop than the previous controller.oller.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.754-759
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• 1992

In this paper, we proposed a mixed H$_{2}$/H$_{\infty}$ optimal controller design method using the parameterization of H$_{2}$ suboptimal controller. The method is based on the minimization of H$_{2}$ performance measure with an H$_{\infty}$-norm constraint. We also derived the necessary and sufficient conditions for existence of solution from the decoupled Riccati equations. And the designed controller has state-space representation.n.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.612-614
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• 1999

In this paper a novel sliding mode control is proposed by using $H_2/H_{\infty}$ controller. this technique is constructed based on the augmented system with a virtual state and make it has the dynamics of the original system and then $H_2/H_{\infty}$ controller has robust characteristics of sliding mode control for existing parameter uncertainty. The reaching phase is excluded by setting initial virtual state value appropriately.