A Shell-Like Induction Electrical Machine

  • João F. P. Fernandes
  • P. J. Costa Branco
Part of the IFIP Advances in Information and Communication Technology book series (IFIPAICT, volume 423)


This paper proposes to recover the concept of spherical induction electrical machines to conceive a shell-like actuator with multi-DOF (Degrees-Of-Freedom). The actuator is formed by a shell stator and a spherical rotor. This work contains the feasibility study of that solution when applied as an active joint actuator in assistive devices. Its electromechanical characteristics are first analyzed using an analytic model that includes: the distribution of the magnetic potential vector and thus the components of the magnetic flux density in the airgap due to a sinusoidal current distribution imposed in the stator; the model also shows the induced electromotive forces and associated current density distribution in the rotor; and at last the radial and tangential components of the force density in the rotor. The shell-like actuator is concretized as an active joint for assisting movement of the lower leg of a typical 70kg person. Based on its requirements, the joint actuator electromechanical characteristics are analyzed according to its sensitivity to a set of electrical and mechanical variables.


Electromechanic energy conversion Electric machines spherical induction motors assistive devices 


  1. 1.
    van Ninhuijs, B.: Feasibility Study of a Spherical Actuator in an Arm Support. Master graduation paper, Electromechanics and Power Electronics Group, Eindhoven University of Technology, Netherlands (August 2011)Google Scholar
  2. 2.
    Suzuki, T., Yano, T., Takatuji, T.: Wafer inspection equipment and system, Japanese Patent No.3641688 (1995)Google Scholar
  3. 3.
    Lee, K.M., Son, H., Joni, J.: Concept Development and Design of a Spherical Wheel Motor (SWM). In: Proc. of 2005 IEEE International Conference on Robotics and Automation, pp. 3663–3668 (April 2005)Google Scholar
  4. 4.
    Kawano, H., Hirahara, T.: Pre-loading Mechanism and Angular Positioning Control Algorithm for Multi-DOF Ultrasonic Motor with a Weight Load. In: Proc. on 18th International Congress on Acoustic, Mo5.I.2, pp.I-569–I-572 (2004)Google Scholar
  5. 5.
    Kagawa, A., Ono, E., Kusakabe, T., Sakamoto, Y.: Absorption of hydrogen by Vanadium-rich V-Ti-Based Alloys, J. Less-Common Met. 172(174), 64–70 (1991)CrossRefGoogle Scholar

Copyright information

© IFIP International Federation for Information Processing 2014

Authors and Affiliations

  • João F. P. Fernandes
    • 1
  • P. J. Costa Branco
    • 1
  1. 1.LAETA/IDMEC, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal

Personalised recommendations