Loopshaping by quadratic constraints on open-loop transfer functions

  • Ichijyo Hodaka
  • Masayuki Suzuki
  • Noboru Sakamoto
Part D Robust Control
Part of the Lecture Notes in Control and Information Sciences book series (LNCIS, volume 241)


The purpose of this note is to propose to execute loopshaping by imposing quadratic constraints on open-loop transfer functions. Quadratic constraints are defined to be consistent with feedback stable systems. Then, a robust stability analysis and a loopshaping method under quadratic constraints on open-loop transfer functions are given. Our results provide a general robustness of feedback systems in terms of open-loop transfer functions, including robustness based on gain and phase margins.


Feedback System Robust Stability Phase Margin Quadratic Constraint Feedback Stability 
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Copyright information

© Springer-Verlag London Limited 1999

Authors and Affiliations

  • Ichijyo Hodaka
  • Masayuki Suzuki
  • Noboru Sakamoto
    • 1
  1. 1.Department of Aerospace Engineering, School of EngineeringNagoya UniversityNagoyaJapan

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