Search results for "transducer"
showing 10 items of 173 documents
Noncontact Air-Coupled Guided Wave Ultrasonics for Detection of Thinning Defects in Aluminum Plates
2001
Ultrasonic guided waves are gaining increasing attention for the inspection of platelike and rodlike structures. At the same time, inspection methods that do not require contact with the test piece are being developed for advanced applications. This paper capitalizes on recent advances in the areas of guided wave ultrasonics and noncontact ultrasonics to demonstrate a superior method for the nondestructive detection of thinning defects simulating hidden corrosion in thin aluminum plates. The proposed approach uses micromachined gas (air)-coupled capacitive transducers for the noncontact generation and detection of guided plate waves. Interesting features in the dispersive behavior of select…
A boundary element model for structural health monitoring using piezoelectric transducers
2013
In this paper, for the first time, the boundary element method (BEM) is used for modelling smart structures instrumented with piezoelectric actuators and sensors. The host structure and its cracks are formulated with the 3D dual boundary element method (DBEM), and the modelling of the piezoelectric transducers implements a 3D semi-analytical finite element approach. The elastodynamic analysis of the structure is performed in the Laplace domain and the time history is obtained by inverse Laplace transform. The sensor signals obtained from BEM simulations show excellent agreement with those from finite element modelling simulations and experiments. This work provides an alternative methodolog…
Photovoltaic plant array reconfiguration: Design of a new device
2014
An efficient strategy to improve unequally irradiated PV plants performances is based on the reconfiguration of the connections between the modules. In this paper, an algorithm, for this purpose conceived, is presented. Moreover, the design, realization and finally also the set up of a new reconfiguration system device is fully shown and discussed. The algorithm conceived simulates several possible series-parallel connections under varying irradiation conditions, and determines the optimal modules connection in order to get the maximum output power. In this way, the reconfiguration system may set up the reconfiguration strategy. The reconfiguration system prototype set up, basically consist…
Analysis of the accuracy of fiber-optic strain transducers installed by using composite smart patches
2015
The aim of this work is to investigate the accuracy of fiber-optic strain transducer related to the incomplete load transmission that can occur on composite smart patches used as base support for the installation of such transducer, commonly used for structural monitoring of concrete elements. In detail, since the dimensions of the transducer are generally very small compared to those of the structural element being monitored, attention is given not to the global reinforcement effect, which occurs when the transducer alters the entire strain field of the transversal section of the monitored element, but rather to the so-called local reinforcement effect, which is due to an incomplete load …
Three dimensional reconstruction of intracoronary ultrasound images: roadmapping with simultaneously digitised coronary angiograms
2002
Three dimensional reconstruction of intracoronary ultrasound images offers a better appreciation of the axial relationship of vessel features and permits volumetric assessment, both of which depend critically on the spatial accuracy of the technique. This in turn is dependent on precise longitudinal orientation of the transducer in the vessel. The authors have developed a system which utilises simultaneously digitised fluoroscopic tracking of the radio-opaque transducer to orient the corresponding 2D ICUS images. This system may offer improved spatial accuracy of the three dimensional reconstruction and a means of precise identification of the 2D ICUS image which corresponds with a selected…
Piezoelectric Rainfall Energy Harvester Performance by an Advanced Arduino-Based Measuring System
2018
This paper presents the performances of rainfall energy harvesting through the use of a piezoelectric transducer and an Arduino-based measuring system. Different studies agree on the possibility of generating electricity from rainfall, but to date, a study on measuring the quantity of energy produced during rainfall is still missing. The present study begins with results obtained from laboratory researchers using piezoelectric transducers and oscilloscopes, finalized to measure the energy produced from a single raindrop, and concludes with an ad hoc Arduino-based measuring system, aimed to measure the actual amount of electrical energy produced by a piezoelectric transducer that is exposed …
A virtual instrument for the measurement of IEEE Std 1459-2000 power quantities
2006
In this paper, the authors present a PC-based instrument for the measurement of electrical-power quantities defined in IEEE Std. 1459. The instrument is based on a time-domain technique for the detection of the fundamental and harmonic components of voltages and currents. The time-domain strategy was originally developed by the authors for three-phase, three-wire systems. In that paper, the strategy had been extended to both three-phase, four-wire and single-phase systems. Simulation tests were carried out to assess the uncertainty contribution of the proposed strategy in the absence of the measurement transducers. Moreover, the accuracy of the PC-based instrument with its transducers was e…
New Solution for Telescopic Robotic Arm
2014
This paper deals with a Robotic arm actuated by a monomobil telescopic planetary gear and servo DC motor. Experimental model of robot was designed and manufactured at the Faculty of Engineering from Sibiu, (Patent no. 112418 CI6.B25J 18/02). The Servo DC as actuator drives a reel. Wires on the reel will produce displacement of telescopic modules from robotic arm structure. The reference as a voltage for future arm displacement is provided by a PWM generator. The rotation of the reel in one way or another has the effect of lengthening or shortening robotic arm. Robotic arm length is directly related to the PWM signal. Control of robotic arm positioning is done with a linear transducer.
The Use of Accelerometers and Gyroscopes to Estimate Hip and Knee Angles on Gait Analysis
2014
In this paper the performance of a sensor system, which has been developed to estimate hip and knee angles and the beginning of the gait phase, have been investigated. The sensor system consists of accelerometers and gyroscopes. A new algorithm was developed in order to avoid the error accumulation due to the gyroscopes drift and vibrations due to the ground contact at the beginning of the stance phase. The proposed algorithm have been tested and compared to some existing algorithms on over-ground walking trials with a commercial device for assisted gait. The results have shown the good accuracy of the angles estimation, also in high angle rate movement.
A new high accuracy software based resolver-to-digital converter
2004
Tracking resolver-to-digital conversion (R/D converter or simply RDC) has emerged as one of the most robust method for obtaining high resolution position and angular speed information from resolvers. In this paper a low cost software based RDC is presented. The main features are: high accuracy, simple set up, high reliability and stability and good performances. Some experimental results, showing the capabilities of the proposed system, are presented and discussed. An output signal comparison between the proposed RDC and a commercial encoder is also presented.