Search for: displacement-measurements
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    Empirical study on effect of surface texture and grain size on displacement measurement of optical flow sensors

    , Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; Oct , 2014 , p. 493-497 ; ISBN: 9781479967438 Azizi, A ; Vossoughi, G ; Sharif University of Technology
    Although, the optical flow sensors which are used in optical mouse have high resolution in measuring displacement, their error refrain us from a precise and reliable measurement. Besides, these sensors require calibration based on the surface. Their error has different sources and the most important is surface texture in micro level. In this research, we have worked to find surface conditions on which sensor measurement is more precise. For this aim, we used an 800 DPI low cost optical flow sensor. For making different surface textures and grains, we printed different textures with 600 and 1200DPI resolution on white paper with certain length. Then we used optical flow sensor for measuring... 

    Fibre position effects on the operation of opto-pair fibre displacement sensors

    , Article Optics and Laser Technology ; Volume 43, Issue 4 , 2011 , Pages 814-819 ; 00303992 (ISSN) Jafari, R ; Golnabi, H ; Sharif University of Technology
    In this article, two optical-fibre probes used in displacement measurements are reported. In one arrangement, two optical fibres with protective buffer jackets are placed together, while in the second arrangement, the protective buffer jackets are removed and the two fibres are placed with the claddings in contact, with a concomitant smaller centrecentre distance. As the core and cladding diameters are the same in both probes, the effect of the centrecentre distance on double-fibre designs can be investigated. The reflected output powers are recorded for the probes as a function of the axial distance from a reflective surface. A theoretical model is also implemented, which considers the... 

    On Bayesian active vibration control of structures subjected to moving inertial loads

    , Article Engineering Structures ; Volume 239 , 2021 ; 01410296 (ISSN) Moradi, S ; Eftekhar Azam, S ; Mofid, M ; Sharif University of Technology
    Elsevier Ltd  2021
    This study introduces a novel Bayesian framework for online and real-time vibration control of beam type structures, which represent a comprehensive control system associated with input-state algorithms. Control design systems typically require knowledge of system states, which in structures are displacements and velocities at some degrees of freedom. Currently, full-field measurements of displacements and velocities in large structural systems are not feasible. Also, properties of the moving inertial loads as key parameters in control designs are assumed known; however, in practice, measuring their characteristics is a challenging issue. As a remedy, an observer is required to estimate...