The invention developed is a piezoelectric stimulus-response quantification-based gravimeter (PEG). The PEG takes a completely innovative approach towards utilization of the piezoelectric element — quantifying the gravitational effects on them. In this way, the piezoelectric element can: (1) generate an electric charge in response to mechanical deformation, and (2) be mechanically deformed by applying electric charges. This is known as the converse-piezoelectric effect. Piezoelectric elements can be used to precisely inject energy for exciting vibratory frequencies within the element and housing, enabling the element to be used for quantifying subsequently produced electrical output. The gravimeter is capable of measuring numerous other types of physical quantities, such as thermal, magnetic, electrical, electromotive, electromagnetic, and electro-static fields, and providing static and structural information.

Conventional gravimeters typically measure the amount of the opposing forces required to suspend an object or by monitoring an object's freefall rate. This innovative technology uses piezoelectric instrumentation in a completely new way, reversing their role. The piezoelectric transducers are provided with excitation energy, causing a highly reproducible response across a full frequency spectrum. This is known as the piezoelectric stimulus-response effect.

This allows the piezoelectric transducer to take static measurements opposed to the conventional utilization of piezoelectric devices that require a dynamically changing quantity.

Three piezoelectric shear elements with an embedded charge amplifier (left). The small package piezoelectric sensor is used for quantifying gravitational forces (right).

When the pull of gravity is introduced, the original element characteristics are immediately changed along with the fluctuations in gravity. These types of transducers are specifically designed to maximize the gravitational effects of the element's vibratory characteristics. The resultant characteristics are automatically quantified and temperature compensated through vector analyses and data reduction algorithms into gravitational units. This stimulus-response process is highly repeatable, which produces a near exact response or measurement from each collected reading, completely revolutionizing the precision and accuracy achievable.

In addition to structural sensing, the PEG could be used by prospectors and geologists to locate mineral or shell deposits, as well as by construction workers to locate deep underground piping. Its many commercial applications include satellites, supercolliders, crustal motion monitors, seismology monitors, geophysical examination, surveying equipment, petroleum prospecting, mineral prospecting, security monitoring, motion detectors, altitude detectors, underground infrastructure detection, and tide prediction.

NASA is actively seeking licensees to commercialize this technology. Please contact Duane Armstrong at This email address is being protected from spambots. You need JavaScript enabled to view it. to initiate licensing discussions. Follow this link for more information: Here .

Sensor Technology Magazine

This article first appeared in the March, 2017 issue of Sensor Technology Magazine.

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