A Novel Two Degrees-of-Freedom Rotary-linear Permanent Magnet Machine

This paper proposes a novel two degrees-of - freedom rotary-linear permanent magnet machine capable of simultaneous rotary and linear motions. The machine features two stator structures, with the rotary and linear motions controlled by windings placed in each respective stator. Firstly, the topology of the machine is introduced. Then, the operating principles and flux paths for rotary and linear motions are analyzed. Subsequently, based on the three-dimensional (3D) finite-element method, the static and dynamic performances of the machine are investigated, including 3D magnetic field distribution, back electromotive force, cogging torque/force, and electromagnetic torque/thrust. Additionally, the performance under spiral motion is compared and analyzed with that under single rotary and single linear motions.