Development of a Novel Miniature Shaftless Motor Using Iron–Gallium Alloy (Galfenol)

In this paper, we presented a novel miniature shaftless motor using the impact drive mechanism (IDM) that takes advantage of the friction and the inertia force to achieve the self-propelling motion. The proposed motor uses two U-shaped iron-gallium alloy (Galfenol) rods as the driving elements. Besides Galfenol, the motor consists of one permanent magnet that provides a bias magnetic field within Galfenol. This bias magnetic field helps the motor to generate the swing motion that can amplify the inertia force of the IDM motor. By controlling swing directions of two motor arms through the driving current, the consistent rotation of the motor is accomplished. The experimental result indicates that the proposed motor is able to achieve an angular velocity of 12.74°/s at 230 Hz. Because of the unique design of the motor, the motor can achieve a linear movement, and the result is briefly reported. The objective of future work is to realize an in-plane three-degree-of-freedom motor that can follow a designated trajectory.