Discrete-time control of continuous systems with approximate decentralized fixed modes

  • Authors:

  • Amir G. Aghdam;Edward J. Davison

  • Affiliations:

  • Department of Electrical and Computer Engineering, Concordia University, Montréal, Qué., Canada H3G 1M8;Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ont., Canada M5S 3G4

  • Venue:
  • Automatica (Journal of IFAC)
  • Year:
  • 2008

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Abstract

In this paper, the discrete-time control of decentralized continuous-time systems, which have approximate decentralized fixed modes, is studied. It is shown that under certain conditions, discrete-time controllers can improve the overall performance of the decentralized control system, when a linear time-invariant continuous-time controller is ineffective. In order to obtain these conditions, a quantitative measure for different types of approximate fixed modes in a decentralized system is given. In this case, it is shown that discrete-time zero-order hold (ZOH) controllers, and in particular, that generalized sampled-data hold functions (GSHF), can significantly improve the overall performance of the resultant closed-loop system. The proposed sampled-data controller is, in fact, a linear time-varying controller for the continuous-time system.