A new topology of a spherical actuator

This paper presents a new topology of an actuator which allows the precise control of the angular position. The proposed system is known as 3-DOF (Three Degrees of Freedom) Spherical Actuator. This actuator can be applied to a robotic eye or joints, as it has 3-DOF in a single block. Such spherical actuator is different among others publications, since it has only three coils, which simplify its construction. The actuator work s injecting different currents values (i₁, i₂, i₃) in each coil, then the generated resultant magnetic field can be positioned at any point of a hemisphere by controlling the currents intensities. The rotor is a spherical shell with a NdFeB permanent magnet inside it. The rotor magnet attempts to align with the resultant magnetic field which was produced by the coils and then rotating movement can be carried out just changing the drive sequence of the coils. Moreover, one mini-camera is attached at the spherical shell to emulate the human eye movement. As result, this paper deals with the design of a spherical actuator with a reduced number of coils, which can be positioned everywhere at the top of a hemisphere.