Hybrid reluctance actuator topology for enhanced linearity and high torque in fast steering mirrors

This paper presents a topology for tilting hybrid reluctance actuators (HRAs) that improves linearity while maintaining high torque output. The primary source of non-linear behavior is identified, and design requirements for the new actuator topology are established using a magnetic equivalent circuit model. Finite element method simulations demonstrate that the proposed design achieves greater linearity and a higher torque to current ratio compared to state of the art actuators. For validation, a fast steering mirror, actuated by the proposed HRA topology, with a $\pm$1° range is designed and implemented. Experimental results confirm a threefold reduction in the variation of the torque to current ratio and stiffness, along with a 76% increase in the torque to current ratio compared to the state of the art HRAs.