Preliminary experimental evaluation of in-situ calibration methods for MEMS-based attitude sensors and Doppler sonars in underwater vehicle navigation

Author(s):  
Giancarlo Troni ◽  
Louis L. Whitcomb
Author(s):  
Michael L. Jonson ◽  
Steven D. Young

In-situ calibration methods using a single spherical-shaped transmitting hydrophone (idealized as a monopole acoustic source) have traditionally been used for radiated sound measurements of turbomachinery performed in the Garfield Thomas 1.22-m diameter water tunnel located at The Pennsylvania State University’s Applied Research Laboratory (ARL Penn State). In this reverberant field, the monopole source containing known transmitting characteristics was used to calibrate acoustic sensors that were either near or far from the source. This method typically works well when the type of source is monopole in nature; however, many acoustics sources can be dipole or quadrupole in nature. In this study we investigated the applicability of using dipole sources in a space such as a well-characterized reverberant tank, and we found through a virtual dipole method that the radiation still appears monopole in the reverberant field. The method was extended for the vibration of a panel (a known dipole source) and once again the monopole assumption for the in-situ calibration for a near-field hydrophone and conventional reverberant hydrophones remained consistent.


2021 ◽  
Author(s):  
Lars Ceranna ◽  
Thomas Bruns ◽  
Christian Koch ◽  
Dominique Rodrigues ◽  
Stephen Robinson ◽  
...  

<p>Infra-AUV is a new EU project that will establish primary measurements standards for low frequency phenomena across the fields of airborne and underwater acoustics and vibration (seismology). Combining expertise from the national measurement institutes and geophysical monitoring station operators, it will develop both high-precision laboratory-based methods of calibration and methods suitable for field use. Infra-AUV will also address requirements for reference sensors that link laboratory calibration capabilities to field requirements for measurement traceability.</p><p>To establish standards in the three technical areas, a variety of calibration principles will be employed, including extension of existing techniques such as reciprocity and optical interferometry, and development of new methods. There will also be an investigation of the potential for in-situ calibration methods, including use of both artificially generated and naturally occurring stimuli such as microseisms and microbaroms. The influence of calibration uncertainties on the determination of the measurands required by the monitoring networks will also be studied.</p><p>The project was strongly motivated by the CTBTO strategy to drive new metrology capability to underpin IMS data. The intention is to maintain interaction with stakeholders, not only in connection with the IMS, but with the broad range of users of low frequency acoustic and vibration data. </p>


Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5521
Author(s):  
Francisco Javier Andrade Chavez ◽  
Silvio Traversaro ◽  
Daniele Pucci

A crucial part of dynamic motions is the interaction with other objects or the environment. Floating base robots have yet to perform these motions repeatably and reliably. Force torque sensors are able to provide the full description of a contact. Despite that, their use beyond a simple threshold logic is not widespread in floating base robots. Force torque sensors might change performance when mounted, which is why in situ calibration methods can improve the performance of robots by ensuring better force torque measurements. The Model-Based in situ calibration method with temperature compensation has shown promising results in improving FT sensor measurements. There are two main goals for this paper. The first is to facilitate the use and understanding of the method by providing guidelines that show their usefulness through experimental results. Then the impact of having better FT measurements with no temperature drift are demonstrated by proving that the offset estimated with this method is still useful days and even a month from the time of estimation. The effect of this is showcased by comparing the sensor response with different offsets simultaneously during real robot experiments. Furthermore, quantitative results of the improvement in dynamic behaviors due to the in situ calibration are shown. Finally, we show how using better FT measurements as feedback in low and high level controllers can impact the performance of floating base robots during dynamic motions. Experiments were performed on the floating base robot iCub.


Sign in / Sign up

Export Citation Format

Share Document