Design of a Moving-magnet Electromagnetic Actuator for Fast Steering Mirror through Finite Element Simulation Method

Abstract

This paper develops a moving-magnet electromagnetic actuator for fast steering mirror (FSM). The actuator achieves a reasonable compromise between voice coil actuator and piezoelectric actuator. The stroke of the actuator is between the strokes of a piezoelectric actuator and a voice coil actuator, and its force output is a linear function of air gap and excitation current within our FSM travel range. Additionally, the actuator is more reliable than voice coil actuator as the electrical connection in the actuator is static. Analytically modeling the actuator is difficult and time-consuming. Alternatively, numerous finite element simulations are carried out for the actuator analysis and design. According to the design results, a real prototype of the actuator is fabricated. An experimental test system is then built. Using the test system, the force output of the fabricated actuator is evaluated. The test results validate the actuator analysis and design.

Piezoelectric and Magnetic Fast Steering Mirrors for Space Optical Communication

“…The magnetic design relies on forces due to tangential variable magnetic reluctance, which offers higher forces than Lorentz forces [7] and more linear forces than normal variable magnetic reluctance [8].…”

Large stroke fast steering mirror for free-space optical communication

“…Although CTEC manufactures also Voice Coil actuators for space applications, another type of magnetic actuators is selected for the M-FSM: The M-FSM exploits a derivation and an integration of the CTEC MICA™ based on variable reluctance forces [6] to drive a mobile part in Rx and Ry motions in an efficient way. Some FSM have already been designed using variable reluctance forces [7,8] to provide improvements above Voice Coil but they exploit attraction forces by reducing the air gap thickness leading to some drawbacks: Contact with attracting poles is responsible for strokes limitations and may generate damages, especially under launching vibrations and shocks. Torques that are not constant versus position are complexifying the drive of such devices.…”