This work presents a new class of micromachined electrostatic actuators capable of producing output force and displacement unprecedented for MEMS electrostatic actuators. The actuators feature submicron high aspect ratio transduction gaps lined up in two-dimensional arrays. Such an arrangement of microscale actuator cells allows the addition of force and displacements of a large number of cells (up to 7600 in one demonstrated array), leading to displacements ranging in the hundreds of microns and several gram forces of axial force. For 50 µm thick actuators with horizontal dimensions in the 1–4 millimeter range, an out-of-plane displacement of up to 678 µm at 46 V, a bending moment of up to 2.0 µNm, i.e., 0.08 N (~8 gram-force) of axial force over a 50 µm by 2 mm cross-sectional area of the actuator (800 kPa of electrostatically generated stress), and an energy density (mechanical work output per stroke per volume) up to 1.42 mJ/cm3 was demonstrated for the actuators.

This work presents a new class of micromachined electrostatic actuators capable of producing output force and displacement unprecedented for MEMS actuators. The actuators feature submicron high aspect ratio transduction gaps lined up in two-dimensional arrays inspired by the cellular structure of animal muscle tissue. Such arrangement of micro-scale actuator cells, allows addition of force and displacements of a large number of cells (up to 7600 in one array demonstrated), leading to displacements in the hundreds of microns range and several gram-forces of axial force. For 50 µm thick actuators with horizontal dimensions in the 1-4 millimeters range, out of plane displacement of up to 678 µm, bending moment of up to 2.0 µNm i.e. 0.08 N (~8 gram-force) of axial force over the 50 µm by 2 mm cross-sectional area of the actuator (800 kPa of electrostatically generated stress), and energy density (mechanical work output per stroke per volume) up to 1.42 mJ/cm3 have been demonstrated for the actuators.

No abstract

This work reports a class of silicon micromachined millimeter scale electrostatic actuator capable of both axial and lateral in-plane displacement with a relatively high energy density. The actuator is comprised of a large-scale integrated array of individual parallel-plate electrostatic cells. The force and displacement of cells within the array add up providing relatively large actuation force and displacement output for the actuators. The nonconventional fabrication process allows realization of submicron transduction airgaps within the actuator cells lowering the actuation voltage. The fabrication process also allows electrical isolation of different cells within the array so that different sections of the actuator ribbon can be actuated independently enabling lateral deformation of the actuator ribbon in addition to axial contraction. Axial inplane displacement of up to 20.50 µm has been shown for a 2010 µm × 1000 µm fabricated actuator. The actuator output force is as high as 10.3 mN demonstrating maximum energy density of 1.11 mJ/cm 3. The same actuator ribbon demonstrated lateral displacement of 10.11 um.

No abstract