Design of One Rotary-linear Permanent Magnet Motor with Two Independently Energized Three Phase Windings

Electrical drives employing motors able to directly manage multiple degrees of freedom may result in relevant interest in several application fields, e.g. robotics and tooling machines. In this paper, a new type of rotary-linear permanent magnet motor with one motion of two degrees of freedom has been proposed. Its main performance advantage is its characteristics of decoupling linear and rotary motions comparing another types of rotary-linear motors. The proposed motor consists of two stator three-phase winding systems separately distributed along radial and axial axes. By using independently energized three-phase windings, two space rotating magnetical fields along axial axis and radial axis are achieved, which are utilised to product rotary and linear motion. One special rotor permanent magnet structure capable of generating one radial and one axial magnetical field has been put forward and analyzed to produce enough torque, drag force and decouple rotary and linear motions. Based on the theoretical analysis and calculation, an experimental motor has been designed and its design process has been detailed introduced in the paper. The validity of analysis and design technique has been confirmed by one three-dimension finite element method (FEM) calculation.