Design and Optimization of a Rotary Actuator for a Two-Degree-of-Freedom $z\phi$ -Module

This paper concerns the design and optimization of a rotary actuator of which the rotor is attached to a linear actuator inside a two-degree-of-freedom zφ-module, which is part of a pick-and-place robot. The rotary actuator provides ±180° rotation while the linear actuator offers a z-motion of ±5 mm. In this paper, the optimal combinations of magnet poles and coils are determined for this slotless actuator with concentrated windings. Based on this analysis, the rotary actuator is optimized using a multiphysical framework, which contains coupled electromagnetic, mechanical, and thermal models. Because the rotation angle is limited, both a moving-coil design with a double mechanical clearance and a moving-magnet design with a single mechanical clearance have been investigated and compared. Additionally, the influence of the edge effects of the magnets on the performance of the rotary actuator has been investigated with both 3-D finite-element modeling simulations and measurements.