Analysis of electric machine charateristics for robot eyes using analytical electromagnetic field computation method

Dongwoo Kang, Ju Lee

Research output: Contribution to journalArticle

11 Scopus citations


This paper proposes an electromagnetic field computation method using an interpolation method with sigmoid functions. This method is useful for approximating and developing a 3-D electromagnetic field model. Particularly, the authors have been researching a spherical motor for a robotic eye. The spherical motor has a spherical air-gap unlike the radial air-gap motor or the axial air-gap motor. The spherical motor proposed in this paper realizes three degrees-of-freedom movements with only one motor. As the spherical motor has a complicated coil structure, the 3-D FEM would be essential for calculating torque while the rotor is tilted. However, 3-D FEM requires much computation time and a huge memory capacity to store the results. The electromagnetic field is rapidly calculated using an interpolation torque function proposed in this paper. The improvement of the spherical motor due to our method is verified through experiment, the results of which are compared with simulation data.

Original languageEnglish
Article number6749121
JournalIEEE Transactions on Magnetics
Issue number2
Publication statusPublished - 2014 Feb 1



  • Approximation methods
  • computational electromagnetic
  • humanoid robots
  • interpolation

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