Linear Quadratic Servo Design for Magnetic Levitation Systems Considering Disturbance Forces from Linear Synchronous Motor

  • Kim, Chang-Hyun (Dept. of Electricity, VISION College of Jeonju) ;
  • Ahn, Hanwoong (Satellite Control System Team, Korea Aerospace Research Institute) ;
  • Lee, Ju (Dept. of Electrical Engineering, Hanyang University) ;
  • Lee, Hyungwoo (Dept. of Railway Vehicle System Engineering, Korea National University of Transportation)
  • Received : 2016.04.04
  • Accepted : 2016.10.28
  • Published : 2017.03.01


Recently, the demand of maglev systems in the manufacturing industry for LCD and OLED display panels, which are required to be very clean and possess vacuum systems, has been increasing due to their characteristics such as being non-contact, noise free and eco-friendly. However, it is still a challenge to simultaneously control both the propulsion and levitation for their interactive effect difficult to be exactly measured. In this paper, we proposed a new tuning method for controlling the magnetic levitation force robustly against the levitation disturbance caused by a propulsion system, based on LQ servo optimal control. The disturbance torque of the LSM propulsion system is calculated through FEM analysis in such a way that the LQ servo controller is determined in order to minimize the effect of the disturbance. The robust performance of the proposed LQ servo control method for the in-track type magnetic levitation systems is demonstrated via simulations and experiments.


Supported by : National Research Foundation of Korea(NRF)


  1. M. Morishita and T. Azukizawa, "A new maglev system for magnetically levitated carrier system," Veh. Technol. IEEE Trans., vol. 38, no. 4, 1989, pp. 230-236.
  2. H. W. Lee, K. C. Kim and J. Lee, "Review of Maglev Train Technologies," IEEE Trans. Magn., vol. 42, no. 7, Jul. 2006, pp. 1917-1925.
  3. C. H. Kim, Robust Control for In-Track Type Magnetic Levitation Systems, Ph.D Thesis, Hanyang University, 2015.
  4. J. H. Yang, LQ-PID Controller Design Method of the Frequency Domain Considering the Overshoot for the Second-order System, Ph.D Thesis, Hanyang University, 2010.
  5. C. H. Kim, H. J. Park, J. Lee, H. W. Lee, and K. D. Lee, "Multi-rate optimal controller design for electromagnetic suspension systems via linear matrix inequality optimization," Journal of Applied Physics, vol. 117, no. 17, May 2015, 17B506.
  6. P. K. Sinha, Electromagnetic Suspension Dynamics & Control, Peter Peregrinus Ltd., 1987.
  7. D. Trumper, "Linearizing control of magnetic suspension systems," IEEE Trans. Control Syst. Technol., vol. 5, no. 4, pp. 427-438, 1997.
  8. K. J. Kim, H. S. Han, C. H. Kim, and S. J. Yang, "Dynamic analysis of a maglev conveyor using an em-pm hybrid magnet," J. Electr. Eng. Technol., vol. 8, no. 6, Nov. 2013, pp. 1571-1578.
  9. H. Kwakernaak and R. Sivan, Linear Optimal Control System, 1st ed. Wiley-Interscience, 1972.
  10. M. Athans, Multivarible Control System, Athan's Control Lecture Note, MIT.

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