High force density five degrees of freedom electromagnetic actuator

Short stroke actuators provides the final bit of the motion in precision mechatronics systems. The desired motion has a small range in multiple degrees of freedom. This paper presents such an actuator with five degrees of freedom (X, Y, theta(X), theta(Y), theta(Z)) motion capability. This actuator has a double stator and rotor topology which facilitates the generation of bias magnetic field in the airgap of the actuator without adding magnet reluctance in the path of the winding flux which controls the motion. This feature allows efficient use of the electromagnets since only reluctance for winding is the airgap. Double stator and rotor structure produces the force and torque in similar fashion for both layers, but the two layers help to generate the tip/tilt by using the force generation differentially in radial direction. The actuator feasibility and operation is understood using reluctance based modelling and final design is generated using finite element simulations. The actuator is designed for a given set of motion specifications and the actuator is compared with another actuator to verify the high force density operation.