KSME International Journal

, Volume 17, Issue 12, pp 1855–1866 | Cite as

System modeling and robust control of an AMB spindle : part II a robust controller design and its implementation

  • Hyeong-Joon Ahn
  • Dong-Chul Han


This paper discusses an entire procedure for a robust controller design and its implementation of an AMB (active magnetic bearing) spindle, which is part II of the papers presenting details of system modeling and robust control of an AMB spindle. Since there are various uncertainties in an AMB system and reliability is the most important factor for applications, robust control naturally gains attentions in this field. However, tight evaluations of various uncertainties based on experimental data and appropriate performance weightings for an AMB spindle are still ongoing research topics. In addition, there are few publications on experimental justification of a designed robust controller. In this paper, uncertainties for the AMB spindle are classified and described based on the measurement and identification results of part I, and an appropriate performance weighting scheme for the AMB spindle is developed. Then, a robust control is designed through the mixedμ synthesis based on the validated accurate nominal model of part I, and the robust controller is reduced considering its closed loop performance. The reduced robust controller is implemented and confirmed with measurements of closed-loop responses. The AMB spindle is operated up to 57,600 rpm and performance of the designed controller is compared with a benchmark PID controller through experiments. Experiments show that the robust controller offers higher stiffness and more efficient control of rigid modes than the benchmark PID controller.

Key Words

Robust Control Uncertainty Description and Active Magnetic Bearing 



System matrix




Plant input disturbance


D scaling for theμ synthesis








General plant




Sensitivity function


Complementary sensitivity function


Controller input


Controller input disturbance


Weighting functions


Parameter variation


Natural frequency




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Copyright information

© The Korean Society of Mechanical Engineers (KSME) 2003

Authors and Affiliations

  • Hyeong-Joon Ahn
    • 1
  • Dong-Chul Han
    • 2
  1. 1.Department of Mechanical & Aerospace EngineeringUniversity of VirginiaCharlottesvilleUSA
  2. 2.School of Mechanical & Aerospace EngineeringSeoul National UniversityKorea

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