A Miniature Electromagnetic Linear Actuator with 3D MEMS Coil

As electronic devices continue to shrink in size, the demand for miniature linear actuators (MLAs) with long stroke, high thrust, high output power, and easy control has become increasingly urgent. In response, we present an electromagnetic linear actuator (EMLA) that combines a 3D MEMS coil fabricated in silicon substrate with the classical voice coil actuator (VCA) structure. The EMLA boasts a compact size of ${2}.{20}\times {2}.{65}\,\,\times2.80$ mm, a low weight of 38 mg, and a stroke length of $540 ~\mu \text{m}$ . The actuator’s thrust, mover’s motion, and output power were verified experimentally, with a thrust coefficient of 13.5 mN/A and a maximum current of 600 mA at room temperature. By implementing cooling plates, the maximum current increases to 750 mA, resulting in a thrust of 10.14 mN, a thrust density of 621.2 mN/cm3, a maximum frequency of 250 Hz, an output power of 2.46 mW, and a power density of 150.7 mW/cm3. The EMLA provides stable and predictable thrust, and the motion of the mover conforms to uniformly accelerated linear motion. The actuator’s outstanding performance makes it an ideal solution for MLA in microsystems.