1,720,959 research outputs found
INVESTIGATION OF NON IDEALITY EFFECTS ON AN INDUCTIVE POSITION SENSOR BASED ON EDDY CURRENTS USING NUMERICAL METHODS
No full textThis research describes methods in investigating non-idealities on Inductive
Position Sensors (IPSs) using numerical method casted in the
Discrete Geometric Approach (DGA). These sensors are able to provide
position information by means of eddy currents generated on a metallic
moving object called target. The positions are retrieved by computing
the induced voltages picked from two receivers placed at an operative
air gap from the moving object.
Being the working principle of the sensor based on the eddy currents
firstly a Magneto Quasi-Static (MQS) problem has to be solved.
We provide a simulation tool based on the Boundary Integral Method
(BIM) to predict the performance of the sensor in terms of linearity error.
The advantage with respect to the Finite Element Method (FEM) is
that the number of Degrees of Freedom (DoFs) concerns only the conductor. The results validate the methodology, showing that
measured linearity errors match simulated values.
Secondly, the fact that the stiffness matrix is fully populated put a
limit in the size of the problem to treat. To overcome this limit, we speed up the solution
of the system using the Gauss-Seidel (GS) iterative techniques and the
Fast Multipole Method (FMM). The dissipated power computed
when the FMM is applied is in agreement with the one computed analytically.
Thirdly, a novel methodology to optimize the design of a ratiometric
rotary IPS fabricated in Printed Circuit Board (PCB) technology. The
optimization aims at reducing the linearity error of the sensor and amplitude
mismatch between the voltages on the two receiving (RX) coils.
Distinct from other optimization techniques proposed in the literature,
the sensor footprint and the target geometry are considered as a nonmodifiable
input. This is motivated by the fact that, for sensor replacement
purposes, the target has to fit a predefined space. For this reason,
the shape of the RX coils is modified in order to reproduce the theoretical coil voltages as
much as possible. The optimized RX shape was obtained by means of a
non-linear least-square solver. Comparisons between simulations and
measurements performed on different prototypes of an absolute rotary
sensor show the effectiveness of the optimization tool. The optimized
sensors exhibit a linearity error below 0.1% of the Full Scale (FS) without
any signal calibration or post-processing manipulation.
Then, we show that each target–receiver pair needs the adoption of
a different reconstruction formula for the identification of the target position,
whereas in the literature the usual inverse tangent function is
applied for every possible pair. We seek the target–receiver pair that
maximizes the amplitude of the induced voltages on the receivers. The
results show that to achieve the maximum value of the induced voltages,
the best choice is to have a rectangular target and rectangular receivers.
To verify these facts, a simulation and optimization method has
been applied to the rectangular receiver coils on two rotary IPS realized
with PCB technology. This assures a theoretical increment of the induced voltage of more than 57\% with respect to the
commonly used sinusoidal receivers.
Finally, we show for the
first time that the rotary IPS has the potential to provide information about not only about
the position but also deviations from the normal operating region due to physical misalignments. We
use supervised learning techniques such as Random Forest (RF) regressor
to predict rotor shaft misalignments based on induced voltages on
receivers. The model determines both the directions and magnitudes
of these anomalies The measurements confirm the effectiveness of this methods
showing the detected misalignments and the accuracy of the model
PROCEDIMENTO PER UN SENSORE RISONANTE, RELATIVO APPARATO E SENSORE RISONANTE
No full textIl presente trovato è relativo ad un procedimento per sensori di
tipo risonante comprendenti un circuito trasmittente, un circuito
ricevente ed un target. Il trovato si riferisce altresì ad un apparato
comprendente almeno un’unità di elaborazione e un modulo di
memorizzazione, configurati rispettivamente per memorizzare ed eseguire
un programma atto ad attuare detto procedimento e ad un sensore
progettabile ed ottimizzabile mediante il suddetto procedimento
BIOSENSORE E RELATIVO PROCEDIMENTO
No full textIl presente trovato è relativo ad un biosensore elettrochimico per il
tracciamento della posizione di una o più particelle isolanti che scorrono
in un fluido conduttore comprendente una molteplicità di elettrodi, di cui due elettrodi attivi ed almeno una coppia di elettrodi di
misura e riferimento. Il trovato si riferisce altresì ad un
procedimento di utilizzo del biosensore
PROCEDIMENTO DI SUPPORTO ALLA PROGETTAZIONE E RELATIVI APPARATO E PROGRAMMA
No full textIl presente trovato è relativo ad un procedimento di supporto alla
progettazione ingegneristica di un dispositivo implementato mediante un
apparato di elaborazione, che fornisca, per un dispositivo da progettare, un
insieme di combinazioni di parametri di ingresso che permettano al
dispositivo di raggiungere prestazioni prossime ad una
prestazione ottima. Il trovato si riferisce altresì ad un apparato atto ad
eseguire detto procedimento di supporto alla progettazione e ad un
programma di supporto alla progettazione
ENBIOS-2D Lab
No full textENBIOS-2D Lab is a tool to illustrate and to study simple Ion Sensitive Field Effect Transistor structures in two dimensions. Together with its companion tool ENBIOS-1D Lab, it is meant for use as a teaching tool in support of undergraduate or graduate courses on the basic physics of transduction in ion and particle sensors, and to assist early stage researchers getting familiar with some basic concepts in the field.
At the present stage, ENBIOS-2D Lab supports simulation and visualization of DC I-V characteristics, impedance/admittance spectra as well as DC and AC potential/carrier/ion distributions in simple two-dimensional ISFET structures. A broader set of case studies will become available with future releases of the tool.
The companion ENBIOS-1D Lab tool offers the possibility to simulate simple Electrolyte/Insulator/Semiconductor systems in one-dimension.
The physical system is modelled with the Poisson/Boltzmann (DC) and Poisson/Nernst/Planck - Poisson/Drift/Diffusion (AC small signal) equations coupled to the site-binding charge model equations at the Electrolyte/Insulator interfaces. Dedicated models are implemented for the frequency and salinity dependence of the electrolyte electrical permittivity and the temperature dependence of the ions' mobility (in water solvent).
ENBIOS-2D Lab is powered by ENBIOS, (Electronic Nano-BIOsensor Simulator), a general purpose three-dimensional Control Volume Finite Element Method (CVFEM) simulator developed in-house at the University of Udine - Italy. ENBIOS simulates in three dimensions (3D) the DC and AC small signal impedance response to ions and micro/nanoparticles of three-dimensional devices made of semiconductor, insulator and electrolyte materials
Design Optimization of PCB-Based Rotary-Inductive Position Sensors
No full textThis paper introduces a novel methodology to optimize the design of a ratiometric rotary inductive position sensor (IPS) fabricated in printed circuit board (PCB) technology. The optimization aims at reducing the linearity error of the sensor and amplitude mismatch between the voltages on the two receiving (RX) coils. Distinct from other optimization techniques proposed in the literature, the sensor footprint and the target geometry are considered as a non-modifiable input. This is motivated by the fact that, for sensor replacement purposes, the target has to fit a predefined space. For this reason, the original optimization technique proposed in this paper modifies the shape of the RX coils to reproduce theoretical coil voltages as much as possible. The optimized RX shape was obtained by means of a non-linear least-square solver, whereas the electromagnetic simulation of the sensor is performed with an original surface integral method, which are orders of magnitude faster than commercial software based on finite elements. Comparisons between simulations and measurements performed on different prototypes of an absolute rotary sensor show the effectiveness of the optimization tool. The optimized sensors exhibit a linearity error below 0.1% of the full scale (FS) without any signal calibration or post-processing manipulation
Fast computation of eddy currents for multiple conductors
No full textIn this work the solution of the eddy current problem for slowly moving conductors is investigated with the volume integral formulation of the EFIE. If in one hand the formulation gives the possibility to mesh only the conductors, if embedded in a uniform insulator, on the other hand the inductance matrix is fully populated limiting thus the size of the problem. Furthermore, the standard solution implies the reassembling of the stiffness matrix for each position assumed by the moving conductors. This results in a limit in the size of the problem to treat and a relevant cost in the computation time. To overcome this limit, in this work, the mutual coupling part of the system with two conductors is computed on the fly giving thus the possibility to solve problems with a higher number of unknowns. Finally, to speed up the solution of the system, the Gauss–Seidel iterative techniques and the Fast Multipole Method (FMM) are applied to take into account the mutual effects between the conductors. A comparison of the proposed method with a reference one shows the effectiveness of this technique
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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