1,720,987 research outputs found
eSysId: Embedded System Identification for Vibration Monitoring at the Extreme Edge
Full text linkEnabling extreme edge processing functionalities will lead
a breakthrough in the development of the next generation of Structural
Health Monitoring (SHM) systems, thanks to the adoption of sensor–near
data analtycs which will make the structural inference process faster and
more advantageous in terms of power consumption and data volume.
In this work, we specifically endorse this paradigm in the context of
vibration–based diagnostics by proposing a novel, intelligent accelerom-
eter sensor combining, in an embedded device, advanced edge data ana-
lytics implementing System Identification algorithms, and energy–aware
custom hardware supporting it. The effect of the bit–depth quantization
of the collected signal on the quality of the retrieved structural param-
eters is assessed; moreover, a cost–benefit analysis is also encompassed,
showing how the developed solution might be globally more advanta-
geous from an energy point of view, reaching up to 10x power saving if
compared with standard alternatives
Design and Prototype Development of a Low-cost Blood Flow Simulator for Vascular Phantoms
No full textForce Sensor for Instrumented Patellar Prostheses: Development and Characterization
Full text linkThe development of an instrumented patellar prosthesis, able to measure the contact forces at the patellofemoral joint, can significantly aid in investigating the causes of total knee arthroplasty failures due to patellar complications. This study focuses on developing and validating an instrumented patellar prosthesis to measure contact forces in the patellofemoral joint. A piezoresistive force sensor was characterized and integrated into a conditioning circuit, with the aim of its implementation in the prosthesis. To measure medial and lateral forces independently, the sensors were trimmed in half. Compression tests (up to 2000 N) assessed sensor performance in terms of linearity (R2 = 0.998 intact vs. 0.989 trimmed), repeatability (0.9% intact vs. 0.8% trimmed), and accuracy (1.7% intact vs. 2.3% trimmed) for forces up to 250 N. Higher force levels resulted in increased errors, but at a rate still comparable to that of existing sensors in the literature. Key considerations for the design of the instrumented prosthesis, such as minimizing point and shear loads, were identified. A prototype prosthesis capable of housing the sensor was proposed. The integrated system shows potential for improving the understanding of Total knee arthroplasty (TKA) failures through in vitro studies and could serve as an intraoperative tool for the evaluation of bone resections
A Wirelessly-Powered Embedded System for Temperature Measurements of a High Performance Electric Motor Rotor
No full text
A Novel Smart Sensor Node with Embedded Signal Processing Functionalities Addressing Vibration–Based Monitoring
No full textUltrasonic Wireless Power Transfer in Metal Structures using Frequency-Steerable Acoustic Transducers and Impedance Matching
Full text linkUltrasonic Wireless Power Transfer (UWPT) has been widely investigated in recent years as a promising solution for powering inaccessible sensor nodes in structural health monitoring (SHM) applications without affecting materials' in-tegrity and overcoming metal shielding effect. In this work, the Frequency-Steerable Acoustic Transducer (FSAT) has been considered as an innovative device for ultrasonic guided waves-based energy transmission thanks to its directional properties. Power transmission and conversion from ultrasonic waves have been investigated, along with techniques exploiting impedance matching to ensure maximum power transfer and sufficient voltage at the receiver side. More specifically, FSAT's output impedance is measured and two impedance-matching networks are proposed and characterized: a parallel-connected inductor and a magnetic transformer. Experimental results conducted on a 1 mm thick aluminum plate with two FSATs bonded at a 50 cm distance pointed out a maximum received power value of 164 μW at 83 kHz, with a 23 V peak-to-peak voltage in transmission. The received power and voltage are sufficient to energize a low-end MCU and micropower management circuits on a sensor node
Design of a Novel Pulser for Frequency Selective-based Power and Data Transmission
Full text linkThis paper proposes an ultrasonic system based
on an innovative piezoelectric device, the Frequency Steerable
Acoustic Transducer (FSAT). The FSAT’s high directivity can
be exploited for structural inspection, and through-metal data
communication and wireless power transfer. These three func-
tions are fundamental in an autonomous sensor system developed
for condition monitoring, which is a central requirement in
many sectors, such as automotive. A novel pulser, made up of
a signal generator and a power amplifier, has been designed
and simulated, for effectively driving the FSAT transducer.
Experimental results showed that the designed power amplifier
is able to reach a gain of 17.80 dB driving the piezoelectric
transducer with a maximum peak-to-peak voltage of 24 V and
that its bandwidth is [3.1-964] kHz. Experiments have been
carried out showing a great improvement in trasmission using
the designed amplifier
Model-assisted Compressed Sensing for Vibration-based Structural Health Monitoring
Full text linkThe main challenge in the implementation of long-lasting vibration monitoring systems is to tackle the complexity of modern 'mesoscale' structures. Thus, the design of energy-aware solutions is promoted for the joint optimization of data sampling rates, on-board storage requirements, and communication data payloads. In this context, the present work explores the feasibility of the model-assisted rakeness-based compressed sensing (MRak-CS) approach to tune the sensing mechanism on the second-order statistics of measured data by pivoting on numerical priors. Moreover, a signal-adapted sparsity basis relying on the Wavelet Packet Transform is conceived, which aims at maximizing the signal sparsity while allowing for a precise time-frequency localization. The adopted solutions were tested with experiments performed on a sensorized pinned-pinned steel beam. Results prove that the proposed compression strategies are superior to conventional eigenvalue approaches and to standard CS methods. The achieved compression ratio is equal to 7 and the quality of the reconstructed structural parameters is preserved even in presence of defective configurations
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