The purpose of this work is to develop a thin, electromagnetic wobble motor with a large amount of torque, a motor thinner than conventional ones and able to be applied to portable electric equipment. We have developed a basic model of the motor 30 mm in diameter and 5 mm in thickness. In this paper, the basic structure and control method are first presented. Next, the design of the electromagnets and the three types of gear pairs, which have different pressure angles for the reduction mechanism, are presented. Finally, the motor drive experiments are performed using two types of drive: one is a two-phase drive, and the other is a four-phase drive. Three types of gear pairs are also shown. The motor works successfully, and its great potential to be mounted in thin, portable equipments is confirmed.

1. [1] A. Viviani, “Experimental and Theoretical Study of Hypocycloidal Motors with Two-Harmonic Field Windings,” IEEE Trans. on Power Apparatus and Systems, PAS-99-1, p. 292, 1980.
2. [2] I. Hayashi et al., “Am Electromagnetic Cycloid Motor,” J. of the Japan society for precision engineering, Vol.61, No.1, pp. 95-99, 1995 (in Japanese).
3. [3] H. Kimura, S. Hirose, and K. Nakaya, “Development of the Crown Motor,” Proc. ICRA, Seoul, pp. 2442-2447, 2001.
4. [4] K. Suzumori, T. Nagata, T. Kanda, K. Uzuka, and I. Enomoto, “Development of electromagnetic nutation motor (electromagnetic investigation),” Robotics and Mechatronics in JSME, Vol.16, No.3, pp. 327-332, 2004.
5. [5] K. Uzuka, I. Enomoto, and K. Suzumori, “Development of Nutation Motors (1st report, Driving Principle and Basic Characterisitics of Pneumatic Nutation Motor),” Trans. of the Japan Society of Mechanical Engineers, Series C, Vol.72, No.716, pp. 1194-1199, April 2006.
6. [6] K. Uzuka, I. Enomoto, and K. Suzumori, “Comparative Assessment of Several Nutation Motor Types,” IEEE/ASME Trans. on Mechatronics, Vol.14, No.1, pp. 82-91, February 2009.
7. [7] M. Miyake, K. Suzumori, and K. Uzuka, “Development of a Flat Electromagnetic Nutation Motor,” Proc. of The 4th Int. Conf. on Manufacturing, Machine Design and Tribology, pp. 65-66, April 2011.
8. [8] T. Nagata, K. Suzumori, T. Kanda, K. Uzuka, and I. Enomoto, “Electro Direct-Drive Stepping Motor for Robots,” IEEE ICRA2004, pp. 4493-4498, 2004.
9. [9] K. Suzumori, K. Hori, and T. Miyagawa, “A Direct-Drive Pneumatic Stepping Motor for Robots: Designs for Pipe-Inspection Microrohots and for Human-Care Robots,” Proc. IEEE Int. Conf. on Robotics ond Auromarion, pp. 3047-3052, 1998.
10. [10] K. Okamoto, K. Suzumori, T. Kanda, and Y. Yamada, “Development of three-chamber micro pneumatic wobble motor,” The 6th Machine Design and Tribology Division in JSME, pp. 265-297, 2006.
11. [11] General Catalog of KHK, KOHARA GEAR INDUSTRY Co., Ltd.