Imperial College London
Portrait Picture

Professor Tom Pike

Faculty of Engineering, Department of Electrical and Electronic Engineering

Professor of Microengineering
 
 
 
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Contact

 

+44 (0)20 7594 6207w.t.pike

 
 
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Location

 

604Electrical EngineeringSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Liu:2016:10.1063/1.4944709,
author = {Liu, H and Pike, WT and Dou, G},
doi = {10.1063/1.4944709},
journal = {Journal of Applied Physics},
pages = {124508--1--124508--10},
title = {A seesaw-lever force-balancing suspension design for space and terrestrial gravity-gradient sensing},
url = {http://dx.doi.org/10.1063/1.4944709},
volume = {119},
year = {2016}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We present the design, fabrication, and characterization of a seesaw-lever force-balancing suspension for a silicon gravity-gradient sensor, a gravity gradiometer, that is capable of operation over a range of gravity from 0 to 1 g. This allows for both air and space deployment after ground validation. An overall rationale for designing a microelectromechanical systems(MEMS) gravity gradiometer is developed, indicating that a gravity gradiometer based on a torsion-balance, rather than a differential-accelerometer, provides the best approach. The fundamental micromachined element, a seesaw-lever force-balancing suspension, is designed with a low fundamental frequency for in-plane rotation to response gravity gradient but with good rejection of all cross-axis modes. During operation under 1 g, a gravitational force is axially loaded on two straight-beams that perform as a stiff fulcrum for the mass-connection lever without affecting sensitive in-plane rotational sensing. The dynamics of this suspension are analysed by both closed-form and finite element analysis, with good agreement between the two. The suspension has been fabricated using through-wafer deep reactive-ion etching and the dynamics verified both in air and vacuum. The sensitivity of a gravity gradiometer built around this suspension will be dominated by thermal noise, contributing in this case a noise floor of around 10 E/Hz−−−√10 E/Hz (1 E = 10−9/s2) in vacuum. Compared with previous conventional gravity gradiometers, this suspension allows a gradiometer of performance within an order of magnitude but greatly reduced volume and weight. Compared with previous MEMS gravity gradiometers, our design has the advantage of functionality under Earth gravity.
AU  - Liu,H
AU  - Pike,WT
AU  - Dou,G
DO  - 10.1063/1.4944709
EP  - 1
PY  - 2016///
SN  - 0021-8979
SP  - 124508
TI  - A seesaw-lever force-balancing suspension design for space and terrestrial gravity-gradient sensing
T2  - Journal of Applied Physics
UR  - http://dx.doi.org/10.1063/1.4944709
UR  - https://aip.scitation.org/doi/full/10.1063/1.4944709
UR  - http://hdl.handle.net/10044/1/39067
VL  - 119
ER  -
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