Large-Displacement Vertical Electrostatic Microactuator Dynamics using Duty-Cycled Softening/Stiffening Parametric Resonance

Electrostatic microactuators with large vertical scanning range (several hundred microns) at high frequency (hundreds to thousands of hertz) and chips sizes compatible with endoscopic microscopy have recently been demonstrated based on parametric resonance. This paper examines the use and modeling of mixed softening/hardening dynamics to help produce large ranges of motion in this class of mirrors. Origin of spring stiffening behavior in actuator design is described, followed by non-dimensional analysis of actuator motion trends. Experimental results are presented for a sample actuator design with up to 480 μm displacement at 1225 Hz and 60 V. Comparison to predicted trends and comments on benefits and limitations of modeling are provided.

Amplifying transmission and compact suspension for a low-profile, large-displacement piezoelectric actuator

A low-profile, piezoelectrically-driven microactuator is presented that achieves very large stroke lengths within size constraints suitable for certain endoscopic microscopy applications. The actuator utilizes a transmission consisting of lever arm and chevron-beam structures to amplify high-force, low-displacement motion of a ceramic lead-zirconate-titanate (PZT) brick into large displacement of a translational platform. For ±120 V input, a full range of 486 μm of motion is achieved, with natural frequency greater than 500 Hz. This corresponds to an anticipated In addition, the lateral translational platform is supported by a redesign of common folded silicon flexures to provide large transverse and vertical stiffness when the width of the actuator is limited.