H∞ Controller Synthesis for Networked Control Systems with Time Delay System Approach

Abstract—In modern control systems, physical plant, controller, sensors and actuators are difficult to be located at the same place, and hence these components need to be connected over network media. When feedback control system is closed via a communication channel, then the control system is classified as a Networked Control System (NCS). The introduction of communication network gives significant advantages, such as reduced installation and maintenance cost and increased system agility. In the other hand, the use of communication network will lead to intermittent losses or delays of the information and may decrease the performance and cause instability.

This paper investigates the problem of H∞ controller synthesis for (NCS). It is well known that H∞-norm constraint can be used to provide a prespecified disturbance attenuation level, and alternatively to analyze robust stability of dynamical system.The NCS is modelled as a time delay system. The physical plant and controller are in continuous time. Two network features are considered: signal transmission delay and data packet dropout. Our objective is focused on the design of state feedback controller which guarantee asymptotic stability of the closed-loop systems. The proposed methods are given in the terms of Linear Matrix Inequality (LMI). If this LMI conditions feasible, a desired controller can be readily constructed. Finally, we consider an unstable system for numerical example. It is shown that the state feedback controller proposed here make the closed-loop system stable with or without input disturbance.

Keywords— H∞ Controller, Networked Control Systems (NCS), Time Delay systems, Linear Matrix Inequality (LMI)

Proceeding of 2011 International Conference on Electrical Engineering and Informatics

17-19 July 2011, Bandung, Indonesia

IEEE Catalog Number: CFP1177H-CDR, pp.714-718

An LMI Approach to H∞ Performance Analysis of Continuous-Time Systems with Two Additive Time-Varying Delays

Abstract. This paper investigates the problem of H∞ performance analysis for continous–time systems with two additive time-varying delays in the state. Our objective is focused on stability analysis of a continuous system with two time-varying delays with an H∞disturbance attenuation level γ. By exploiting Lyapunov-Krasovski functional and introducing free weighting matrix variables, LMI stability condition have been derived.

Keywords: H∞ performance analysis; Linear Matrix Inequality (LMI); time delay systems

ITB Journal of Engineering Science, Vol. 43, No. 2, 2011, pp.127-138

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