A self-attachable and self-alignable micro electromagnetic linear actuator

Abstract

This paper presents the design, fabrication and characterization of a novel micro electromagnetic linear actuator, which exhibits two highlights: slider self-alignment and self-attachment capability. Such characters are realized by deliberately utilizing the attractive force between the permanent magnets (Nd2Fe14B) of the slider and nickel ferromagnetic cores embedded in the stator. Actuation is achieved via thrust from both meander micro copper coils and nickel ferromagnetic cores in the stator to the permanent magnets of the slider. The actuator is fabricated by the micro machining process. The surface magnetic property of the slider is simulated and experimentally measured. The eccentric experiment is conducted to evaluate the attraction force between the slider and stator, which proves its self-attachment characteristics. The device is actuated by two-phase sinusoidal currents with a 0.5 A amplitude under an open-loop condition. The slider demonstrates self-alignment movements before moving forward when misalignment occurs. The actuation experimental results show that the average velocity of the slider reaches 4 mm s–1 and 12 mm s–1 at 10 Hz and 30 Hz, respectively. Further increasing the input frequency to 50 Hz leads to the unsteady actuation state, indicating the actuator bandwidth is less than 50 Hz under an open-loop condition.