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Accelerometer | Theory of Operation
Theory of Operation
By modelling the primary transducer, we can predict the mechanical response of
the accelerometer to different accelerations. The primary transducer of nearly
all accelerometers can be modeled as a mass-spring-dashpot system.
It
can be shown that the motion of the seismic mass can be described as:
(1) 
- where:
- m is the seismic mass,
- c is the damping constant,
- k is the spring constant,
- z is the position of the seismic mass
relative to the housing (z = y - x),
- y is the absolute position of the mass,
and
- x is the absolute position of the
accelerometer housing.
Equation 1 can be rewritten in the general form of the 2nd Order
Ordinary Differential Equation as:
(2) 
- where:
- [[omega]]n is the natural frequency and
- [[zeta]] is the damping ratio.
The natural frequency can be written as:
(3) 
.
And,
the damping ratio is given by:
(4) 
.
Last Updated: January 16, 2000, beam@bits.me.berkeley.edu
Copyright © 1993-1995, 2000, Pamela A. Eibeck and Brandon Muramatsu
Original WWW Conversion by Winston Wang, 1994
WWW ReConversion by Brandon Muramtasu, 2000