Exploring and
Exploiting Resonances in MEMS
Professor Steven W.
Shaw
Michigan
State University
Department
of Mechanical Engineering
In
this presentation I will discuss two types of MEMS (micro-electro-mechanical
systems) with interesting resonance features. These resonances are useful for sensing, for example, by
measuring shifts in resonance peaks that arise due to changes in environmental
characteristics. The first part of
the presentation describes the development of a class of sensors that are capable
of simultaneously measuring multiple resonance shifts using a single input and
a single readout. These
multi-degree-of-freedom micro-systems exploit the linear frequency response of
a proof mass to which are attached several individual sensor oscillators. The proof mass is driven
electrostatically and the measurement scheme exploits vibration modes of the
overall coupled system in which vibration energy is sequentially localized in
the individual sensor oscillators.
The general features of these systems will be described, along with
experimental verification and some design issues related to further
development. The second topic
deals with parametric resonance in a general class of electrostatically excited
devices. These systems feature
instabilities that have some desirable features for sensing. However, the nonlinear responses of
these devices are often observed to vary between hardening and softening,
depending in a complicated manner on the excitation and system parameters. We describe a simple model for such
systems that captures these phenomena in a systematic manner. By employing appropriate scaling, a
perturbation method can be applied to provide a complete description of the
response and its dependence on system and excitation parameters. Experimental verification of the theory
is demonstrated, and it is shown how these results can be used to assist in the
design of devices that utilize parametric resonance.
The
work described is being carried out in collaboration with Professors Kimberly
Turner and Jeff Moehlis of the University of California-Santa Barbara, and
graduate students Jeff Rhoads (MSU) and Barry Demartini (UCSB).
Friday, October 12,
2007
3:30 – 4:30
p.m.
Rm. 1500 EECS