Modeling and Analysis of a Novel Two-Axis Rotary Electromagnetic Actuator for Fast Steering Mirror

Abstract

This paper focuses on the modeling and analysis a novel two-axis rotary normal-stress electromagnetic actuator with compact structure for fast steering mirror (FSM). The actuator has high force density similar to a solenoid, but its torque output is nearly a linear function of both its driving current and rotation angle, showing that the actuator is ideal for FSM. In addition, the actuator is designed with a new cross topology armature and no additional axial force is generated when the actuator works. With flux leakage being involved in the actuator modeling properly, an accurate analytical model of the actuator, which shows the actuator's linear characteristics, is obtained via the commonly used equivalent magnetic circuit method. Finally, numerical simulation is presented to validate the analytical actuator model. It is shown that the analytical results are in a good agreement with the simulation results.

Design of a Rotary Electromagnetic Actuator with Linear Torque Output for Fast Steering Mirror

“…In another paper of ours [7], we designed a two-axis rotary electromagnetic actuator for our FSM by using the magnetic-flux-biased method which has been successfully used in in fast tool servos [8][9][10] and nanopositioner [11]. By introducing bias flux and designing proper electromagnetic configuration, the actuator has high force density similar to a solenoid, but its torque output is nearly a linear function of both its driving current and rotation angle.…”

“…However, as we showed in Ref. [7], the actuators in the two FSMs named the AFSM and sAFSM have some drawbacks such as additional axial force problem, actuator model with low accuracy and so on. By introducing a new electromagnetic topology and taking flux leakage into consideration, an actuator that overcomes the drawbacks of the AFSM and sAFSM actuators was achieved in Ref.…”

“…By introducing a new electromagnetic topology and taking flux leakage into consideration, an actuator that overcomes the drawbacks of the AFSM and sAFSM actuators was achieved in Ref. [7]. In addition, detailed design of the AFSM and sAFSM actuators was not included in Ref.…”

“…[7], we only focused on the concept design and accurately modeling of our FSM actuator, not including detailed design of the actuator. This paper is motivated by the detailed design of our FSM actuator based on previous study results of Ref.…”

“…This paper is motivated by the detailed design of our FSM actuator based on previous study results of Ref. [7]. The designed actuator in this paper aims to accomplish a balance between torque output, required coil magnetomotive force (MMF) and torque density.…”