Development of a 3 degree of freedom spherical actuator

Development of a 3 degree of freedom spherical actuator Permanent magnet spherical actuators have seen an increase in interest due potential applications in areas like robotics, satellite control and sensors. This work presents one such actuator, along with approaches to multi-dof actuation. A review of relevant magnetic field equations is presented along with modelling methodologies. Selected existing designs are also presented: firstly, the ball-joint like design, which uses a single row of permanent magnets distributed along the equator. Then the deflection-type is presented, which comprises a rotor made up of the spherical tile permanent magnet, and the E-Shape stator design, which uses blade shaped back iron for the rotor to reduce weight, and finally an overview of a reaction sphere design for satellite attitude control is given, which used spherical top shaped permanent magnet positioned on the vertex of a dodecahedron. The designed actuator is also presented, along with a 3D model and its magnetic and torque modelling, as well as comparison between the obtained magnetic flux density values with the ones obtained by means of FEM. Finally, some variations on the design are analysed.