Structural design and simulation-based optimization of a PCB-stator axial-flux electromagnetic rotary actuator for fuze safety-and-arming mechanisms

Conventional fuze safety-and-arming (S&A) mechanisms often rely on setback or centrifugal forces, whereas electrically driven pin pullers and motor–lead-screw units may require relatively long axial travel. This study presents a printed circuit board (PCB)-stator axial-flux electromagnetic rotary actuator designed to switch between functional positions through 180° rotor rotation while retaining a potential reverse-drive path. The investigation focuses on the electromagnetic drive subsystem rather than the complete S&A mechanism. An electromechanical model was established using the voltage balance, back electromotive force, torque–current relation, rotor inertia, and equivalent resisting torque. A three-dimensional transient finite-element model was used to evaluate the effects of air gap and permanent-magnet thickness on 180° positioning time. The spatial magnetic-field distribution, friction-related resistance, and eddy-current losses were considered when interpreting the results. Within the investigated air-gap range of 0.5–1.1 mm, the shortest positioning time in the air-gap sweep was 45.0 ms at 1.1 mm. With this gap fixed, a magnet thickness of 1.2 mm yielded a finite-element positioning time of 42.6 ms, compared with 40.3 ms from the analytical model (a 5.40% difference relative to the finite-element result). A simplified prototype reached 180° in 35.8 ms at 5 A, compared with 33.98 ms from a simulation using the corresponding low-friction boundary conditions (a 5.08% difference relative to the measured time). These results support the drive model under the tested conditions; full-device locking, release, reverse recovery, and cyclic reliability remain to be verified.