TABLE OF CONTENTS Chapter written by Andr MIGEON and Anne-Elisabeth LENEL.
Accelerometers have existed for several decades and they are always in constant evolution because they influence the performance of many devices in a strategic way. In the past 15 years in particular, thanks to micro technologies, there has been enormous progress in precision, linearity, stability and also size and electric consumption of the sensors.
There is a great diversity of applications of accelerometers in various fields like automotive, aeronautics, instrumentation, medical devices and automation. We will limit this module to the presentation of relevant physical principles and their associated technologies, and we will present some examples of applications.
The term "accelerometer" is in general used for a device which measures linear (not angular) acceleration.
This device measures the inertial force exerted on the seismic mass. It is attached to the measured object and does not need a reference.
This device measures the distance between the measured object and reference point. The reference point should be stable or moving with constant speed. Acceleration is then given by double differentiation of this distance. Relative accelerometers are mainly used to measure vibrations from a distant stable point (e.g. by laser vibrometers).
This chapter covers absolute accelerometers. Acceleration sensors can be classified according to the physical principle they use:
a direct measurement of a force (piezoelectric sensor, sensor with force balance); or
an indirect measurement, by means of displacement or deformation of a sensing element.
We can also classify these...
