Design of a small fast steering mirror for airborne and aerospace applications

Abstract

This thesis presents the analysis and design of a small advanced fast steering mirror (sAFSM) for airborne and aerospace platforms. The sAFSM provides feedback-controlled articulation of two rotational axes for precision optical pointing. The design, useful for both disturbance rejection and high-speed scanning applications, incorporates a flux steering actuator with a ring core magnetic configuration. The novel magnetic concept enables a dramatic size reduction compared with heritage systems. The moving armature is supported with a combination of elastomer sheets and active position control. Local angular and mirror-normal displacement is sensed with integrated capacitive sensors. Analysis content includes specification of performance requirements based on a realistic deep-space laser communication mission, magnetic equivalent circuit and three-dimensional magnetostatic finite element analysis of the actuator, and a 3D structural optimization of the moving armature modal frequencies. The resulting design is one iteration removed from a flight -ready model. The sAFSM hardware is in fabrication, and anticipated performance exceeds 10 krad/s2 angular acceleration, 10 mrad range, and 9 kHz closed-loop bandwidth.