Robust Control of Magnetic Levitation Systems by Means of HControl/μ-Synthesis

Kenzo Nonami, Hidekazu Nishimura, Weidong He

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


This study is concerned with an application of Hcontrol and μ synthesis to magnetic levitation systems which have special flexible structures and the solution of the spillover problem. At first, we show the typical spillover phenomenon caused by the interaction between the control system and the flexible structure system using PID control. Next, applying mixed-sensitivity Hcontrol to the magnetic levitation system, we design the control system for it without spillover and describe in detail how to design an controller. Finally, we analyze the structured singular value and design the μ controller using D-K iteration. In this paper, we assume the magnetic levitation system as an uncoupled system between the X and Y directions for simplicity, which is the third-order system with the exception of the guideway. As a result, it has been clarified that the Hcontroller and μ-controller have the characteristics of two kinds of filters, a low-pass filter and a notch filter. It is found that the μ controller is superior to the Hcontroller in terms of robust stability and robust performance. From experiments, we obtained good data on the magnetic levitation without spillover.

Original languageEnglish
Pages (from-to)513-520
Number of pages8
JournalJsme International Journal. Ser. C, Dynamics, Control, Robotics, Design and Manufacturing
Issue number3
Publication statusPublished - 1994 Feb 1
Externally publishedYes


  • Experiments
  • Flexible Guideway
  • Flexible Slider
  • Magnetic Levitation System
  • Mixed-Sensitivity Problem
  • Spillover HControl

ASJC Scopus subject areas

  • Engineering(all)


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