A single-layer tilting actuator with multiple close-gap electrodes

Abstract

We report on the design, fabrication and characterization of a novel tilting electrostatic actuator, fabricated by using a single layer of a silicon on insulator (SOI) wafer and investigate, both theoretically and experimentally, the electromechanical behavior of the device. The actuator incorporates high aspect ratio comb-like electrodes oriented in the direction parallel to the rotation axis of the tilting element. An increase in the tilting angle is accompanied by a decrease in the distance between the electrodes and by an increase of the actuating torque. Simultaneously, the overlap area between electrodes located farther apart the axis shrinks, resulting in a 'restoring' torque in the opposite direction. The electromechanical behavior and stability of the device were investigated using a simplified model of the actuator and verified by a coupled three-dimensional simulation. Model results suggest that by changing the design parameters, the actuator characteristic can be tailored in a large range. Devices of three different configurations incorporating elastic torsion axes or bending flexures were fabricated and characterized and both static and resonant responses, typical for parametrically excited nonlinear oscillators, were registered. Theoretical and experimental results indicate that the suggested architecture can be efficiently used for the static and dynamic operation of electrostatic tilting devices.

A numerical‐analytical methodology for acquiring the electrical force of carbon nanotube–based nanoactuator assuming an out‐of‐plane electrodes arrangement

“…However, as explained before, this parallel‐plates actuation arrangement, certainly robust and easy to manufacture, do have some drawbacks such as lower actuator deflection range of travel mainly limited by the short‐circuit problems (the pull‐in instability, Figure C). Therefore, since the stroke is considered to be an important characteristic parameter in any design of any kind of microactuator and nanoactuator, few previous works were reported to be successful in extending the range of travel of electrostatically actuated microsystem and nanosystem . These reported designs presented excellent success in amplifying the displacements of the electromechanical microdevice and nanodevice, however revealed practical limits on the amplification factor, as well as penalties on the overall actuator performance.…”

Excitation of large-amplitude parametric resonance by the mechanical stiffness modulation of a microstructure

“…However, special arrangements of the electrodes make it possible to tailor the nonlinear characteristics of the electrostatic force through control of the distribution of the fringing fields [11,24]. This kind of actuation is widely used in resonant tilting microdevices, mainly for scanning applications [25,26]. Kinematical excitation, which is commonly implemented for parametric excitation of large-scale structures [27,28] and is based on the vibrational motion of the attachment point of a beam, was recently used in microdevices [29,30].…”