A compact electromagnetic micro-actuator using the meander springs partially exposed to magnetic field

We present the design, fabrication, and testing of a compact electromagnetic micro-actuator using meander springs that are partially exposed to the magnetic field. The previous electromagnetic micro-actuators using cantilever springs require large electromagnetic force for large displacement actuation and therefore require high-current input and a large magnet. The previous electromagnetic actuators using low-stiffness meander springs are limited in large displacement actuation because actuation forces cancelled each other due to changes in the current path under the magnetic field. In this paper, we compare two prototypes: a conventional prototype F with the meander springs exposed fully to the magnetic field and the present prototype P with the meander springs partially exposed to the magnetic field. In the experimental study, the amplitude of prototype P is measured as 30.49 ± 0.36 µm at the 40 mA square input current, while the amplitude of prototype F is measured as 26.02 ± 0.65 µm. The amplitude of prototype P is 17.2 % larger than that of prototype F, verifying the effect of partial exposure of the meander springs to the magnetic field. Therefore, we experimentally demonstrate the large-displacement actuation performance of the present actuator using the partial exposure of the meander springs to the magnetic field.