Basic characteristics of a hexahedron-octahedron based spherical stepping motor

A spherical stepping motor with a hexahedron based rotor and an octahedron based stator is developed. The drive principle of the developed spherical motor is an expansion of the drive principle of a conventional stepping motor. The motor has three degrees of freedom. As the motor structure is spherically symmetric, the control method is same and simple in any direction. The experimental results show that the rotor moves in almost any direction by switching the connection between the three phase currents of the conventional motor driver and the armature coils. The motor speed is controlled from 0.05rpm to 180rpm and the maximum output torque is 0.013Nm. The developed motor is air-cored type without back yoke. Iron-cored, back yoked spherical motor will be an omnidirectionaly high torque spherical motor. A group of the polyhedron based spherical stepping motors is also introduced.