Design of a bidirectional MEMS actuator with high displacement resolution, large driving force and power-free latching

This paper describes the design and ANSYS modeling of a bidirectional thermal inchworm MEMS actuator featuring high actuation resolution (0.1@mm) combined with large driving force (100mN) and power-free latching. A promising application of this device is for precision in-package positioning of optical fibers, but the actuator also has potential for wider use. The inchworm mechanism includes two E-shaped metallic actuators facing each other and a pusher between them that couples to a moveable object such as an optical fiber. Nickel is chosen as the material of the actuators due to its desirable electrical, thermal, and mechanical properties, and availability in fabrication facilities. Electrothermal actuation is used to move the pusher as well as the optical fiber in the desired direction by inputting electric currents in a particular sequence. A transient thermal-mechanical analysis shows the feasibility of the input sequence that drives the inchworm actuation.