Combined Electrostatic/Electromagnetic MEMS Actuators
Abstract
In this work, one and two degrees of freedom (DOF) lumped mass models of Micro-
Electro-Mechanical System (MEMS) actuators are introduced, investigated, and compared
to experimental results. A one degree of freedom system representing the actuators out-of plane
bending motion under the electrostatic excitation is demonstrated. The capacitive
gap between the movable plate and stationary electrode decreases when the microplate
inclination angle is accounted for in the model.
We investigate experimentally the primary, superharmonic of order two, and subharmonic
of order one-half resonances of an electrostatic MEMS actuator under direct excitation.
We identify the parameters of a 1-DOF generalized Duffing oscillator, model that
represents it. The experiments were conducted in soft vacuum in order to reduce squeeze-
film damping and the actuator response was measured optically using a laser vibrometer.
The predictions of the identified model were found to be in close agreement with the experimental
results. We also identified the power level of process (actuation voltage) and
measurement noise.
A one DOF model of the actuator's torsional motion under the electrostatic torque is
also introduced. It was found that utilizing electrostatic actuation in torsional motion is
not e ffective. The maximum angle obtained was 0.04 degrees at high voltage. Finally, a
novel two DOF model of the MEMS actuator's torsion and bending under electrostatic and
electromagnetic excitation was demonstrated analytically and compared to experimental
results. Torsional motions were driven by a torque arising from a Lorentz force. It succeeded
in generating a large torsion angle, 1 degree at 1.35 T magnetic field density, and
a current of 3.3 mA.
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Cite this version of the work
Ayman Alneamy
(2016).
Combined Electrostatic/Electromagnetic MEMS Actuators. UWSpace.
http://hdl.handle.net/10012/10622
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