Vibration Suppression in the Passively-Supported Direction by Varying Bias Currents in Magnetic Suspension System

Takeshi Mizuno, Asief Javed, Yuji Ishino, Daisuke Yamaguchi, Masaya Takasaki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Vibration in the passively-supported direction is reduced by varying the stiffness in the suspension. The magnetic suspension system using the attractive force of an electromagnet is inherently unstable in the normal direction; active control is necessary to achieve stable suspension. In contrast, it is usually stable in the lateral direction because of the edge effects in the magnetic circuits. However, damping in this direction is quite small so that vibration is easily induced. In this work, varying stiffness controls are applied to suppress the vibration. An experimental apparatus was built to examine the efficacy of the varying stiffness control. It has two electromagnets operated differentially. To adjust the stiffness in the passively-supported direction, the bias current of each electromagnet is varied simultaneously. First, the bias current is varied stepwise. The effect of the amplitude of step on vibration suppression is examined. Then, the bias current is varied continuously to avoid erroneous operations caused by noise included in the sensor signal. The efficacy of approximating the sign function by a continuous function is demonstrated experimentally.

Original languageEnglish
Title of host publication2018 European Control Conference, ECC 2018
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages971-976
Number of pages6
ISBN (Electronic)9783952426982
DOIs
Publication statusPublished - Nov 27 2018
Externally publishedYes
Event16th European Control Conference, ECC 2018 - Limassol, Cyprus
Duration: Jun 12 2018Jun 15 2018

Publication series

Name2018 European Control Conference, ECC 2018

Other

Other16th European Control Conference, ECC 2018
CountryCyprus
CityLimassol
Period6/12/186/15/18

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Control and Optimization

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