Positive Definiteness in Linear Matrix Inequality Problem for H-Infinity Output Feedback Control Problem

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We focus on the positive definiteness in the linear matrix inequality (LMI) problem obtained from H output feedback control problem. In particular, we provide a necessary condition for an inequality constraint of the LMI problem, which is called the coupling constraint, to strictly hold at optimal solutions. It is reasonable to expect that the condition does not hold for most generalized plants. In other words, the strict inequality at the optimal solutions rarely happens in H output feedback control for most generalized plants. Thus, we must apply remedies for constructing a controller after solving the LMI problem.

Original languageEnglish
Article number8637724
Pages (from-to)446-451
Number of pages6
JournalIEEE Control Systems Letters
Issue number2
Publication statusPublished - Apr 2019


All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Control and Optimization

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