A new three degrees of freedom electromagnetic actuator

The design of an electromagnetic actuator rotating around three independent axes is presented. The actuator consists of a spherical armature moving around its center; inside this armature are situated three fixed inductors. When power is supplied, the three phase windings of each inductor develop a moving magnetic field acting along its own plane of symmetry. The spherical armature of the actuator is made of magnetic steel; on the inner face, a thin layer of copper has been fixed. In that way, each inductor and the portion of armature that is in front of it behaves like a linear induction motor. When the inductors are adequately supplied with electricity the armature moves inside a solid angle. The actuator developed by the authors moves inside a cone, with a maximum deviation of +or-30 degrees . To make it work and to have good positioning, the actuator is equipped with sensors that detect the position of the armature. The electric power is supplied by three PWM transistor inverters, one for each inductor.<>