Double Stator Linear-Rotary Actuator with a Single Set of Mover Magnets

Double stator (DS) linear-rotary actuators (LiRAs) are mainly used in machining applications with high force and torque demands, such as milling or turning. The mover of a typical DS LiRA contains two sets of permanent magnets, one arranged as in radial-flux rotating machines and the other as in tubular linear machines. A back iron is sandwiched between these two sets of permanent magnets, rendering the mover heavy and bulky. Consequently, DS LiRAs are not suitable for applications with high dynamics, such as pick-and-place robots in the packaging and semiconductor industries. In order to increase the dynamics of DS LiRAs, two different ironless mover layouts are proposed in this work. The achievable forces and torques are calculated using finite element method (FEM) simulations and compared to the standard DS LiRA. Manufacturing limitations of the proposed mover layouts and their influence on the performance are considered. Moreover, cogging force and cogging torque of the standard and proposed LiRAs are compared. To verify the FEM models used in the analysis, a simplified test setup with a flat mover is presented. The flux linkage is measured and a good agreement with FEM simulations is demonstrated.