Loading...
Search for: calibration
0.007 seconds
Total 217 records

    Kinematic calibration of the hexaglide parallel robot using a simple measurement system

    , Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 853-859 ; 9780791848722 (ISBN) Abtahi, M ; Pendar, H ; Alasty, A ; Vossoughi, G. R ; Sharif University of Technology
    2009
    Abstract
    Because of errors in the geometric parameters of the parallel robots, it is necessary to calibrate them to improve the positioning accuracy for accurate task performance. Traditionally, to perform system calibration, one needs to measure a number of robot poses using an external measuring device. However, this process is often time-consuming, expensive and difficult for robot on-line calibration. In this paper, a methodical way of self-calibrating of Hexaglide parallel robot is introduced. This method is performable only by measuring input joint variables and errors of positioning relative to the desired position in some sets of configurations where in each set the desired position is fixed,... 

    I/Q mismatch calibration of a transmitter using local quadrature oscillator

    , Article Microelectronics Journal ; Volume 55 , 2016 , Pages 82-91 ; 00262692 (ISSN) Zare Fatin, G ; Savadi Osgooei, M ; Fotowat Ahmady, A ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    In this paper a calibration technique for I/Q mismatch of a transmitter is introduced. The calibration technique is based on the fact that all mismatches in I/Q paths can be modeled as the mismatch of the local oscillator quadrature outputs. Based on this fact, a simple tuning scheme for quadrature output of the oscillator is used to calibrate the mismatch of the I/Q transmitter. In addition to quadrature oscillator, gain mismatch of the I/Q paths and LO feedthorugh and leakage is calibrated by using a tunable linear Gm cell in the base band part. In order to demonstrate the proposed technique, a transmitter with 1.8 GHz carrier frequency is designed with auxiliary blocks to extract and... 

    Correction to: parametric study and working fluid selection of modified combined power and refrigeration cycles (MCPRCs) using low-temperature heat sources (Journal of the Brazilian Society of Mechanical Sciences and Engineering, (2018), 40, 1, (30), 10.1007/s40430-018-0971-5)

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 40, Issue 2 , February , 2018 ; 16785878 (ISSN) Rostamzadeh, H ; Ghaebi, H ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    The original version of this article unfortunately contained a mistake. The affiliation of the second author was incorrect. The correct information is given below: Hadi Ghaebi, Department of Mechanical Engineering, Faculty of Engineering, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran. © 2018, The Brazilian Society of Mechanical Sciences and Engineering  

    A fully analog calibration technique for phase and gain mismatches in image-reject receivers

    , Article AEU - International Journal of Electronics and Communications ; Volume 69, Issue 5 , May , 2015 , Pages 823-835 ; 14348411 (ISSN) Nikoofard, A ; Kananian, S ; Fotowat Ahmady, A ; Sharif University of Technology
    Elsevier GmbH  2015
    Abstract
    A systematic approach to I/Q mismatch calibration in image-reject receivers is presented in this paper. A new error detection algorithm is proposed, which automatically calibrates for phase and gain mismatches limiting the performance of image-reject receivers. A dual-loop feedback is employed which looks for the minimum phase/gain error using a 2-dimensional analog-based search algorithm and then finds the minimum value for the error. An experimental CMOS prototype RF front-end for cognitive radio applications operating at 400-800 MHz is proposed and simulated in the 0.18 μm CMOS technology, achieving an image rejection ratio (IRR) better than 55-dB in post-layout simulation. The... 

    Calibration of hexaglide parallel manipulators using only input joint variables

    , Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 861-867 ; 9780791848722 (ISBN) Abtahi, M ; Pendar, H ; Alasty, A ; Vossoughi, G. R ; Sharif University of Technology
    2009
    Abstract
    In the application of parallel robots, it is necessary to calibrate the geometric parameters and improve the positioning accuracy for accurate task performance. Traditionally, to perform system calibration, one needs to measure a number of robot poses using an external measuring device. However, this process is often time-consuming, expensive and difficult for robot on-line calibration. In this paper, a methodical way of self-calibrating of Hexaglide parallel robot is introduced. This method is performable only by measuring input joint variables in some sets of configurations where in each set center of the end-effector is fixed, but orientations are different. Simulations give us an idea... 

    Ultrasound Intensity Exposimetry in Physiotherapy Devices using Micro-Bubbles

    , M.Sc. Thesis Sharif University of Technology Rezayat, Ehsan (Author) ; Zahedi, Edmond (Supervisor)
    Abstract
    Routine ultrasound calibration methods have some restrictions such as: low bandwidth, low frequency resolution, limited spatial resolution, the high cost of test and risk of damage to the transducer when exposed to high powers. In this thesis, a new technique based on microbubble resonance is proposed. Non-linear resonating microbubbles produce harmonics;the first harmonic may be masked by reflection from larger microbubbles as well as unwanted reflections which cause ambiguity in the determination of the amplitude of the excited pressure. Therefore, the second harmonic is used, with a single characteristic peak. In order to model the physical phenomenon, the second harmonic generated in the... 

    Calibration of forming limit diagrams using a modified Marciniak-Kuczynski model and an empirical law

    , Article Materials and Design ; Volume 34 , Feb , 2012 , Pages 185-191 ; 02641275 (ISSN) Ghazanfari, A ; Assempour, A ; Sharif University of Technology
    2012
    Abstract
    The major problem in determining the forming limit diagram (FLD) with the Marciniak-Kuczynski (M-K) model is the necessity of an experimental point in order to find the initial inhomogeneity coefficient and calibrate the diagram. The purpose of the present work is to eliminate this requirement. To do this, the usual assumption of geometrical inhomogeneity has been replaced with material inhomogeneity and it has been shown that the sensitivity of the diagram to variations of the inhomogeneity factor is reduced greatly with the new assumption. Using this advantage and collecting enough experimental data for different materials, an empirical law in terms of sheet thickness has been proposed... 

    Experimental kinematic calibration of parallel manipulators using a relative position error measurement system

    , Article Robotics and Computer-Integrated Manufacturing ; Vol. 26, Issue 6 , 2010 , pp. 799-804 ; ISSN: 07365845 Abtahi, M ; Pendar, H ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
    Abstract
    Because of errors in the geometric parameters of parallel robots, it is necessary to calibrate them to improve the positioning accuracy for accurate task performance. Traditionally, to perform system calibration, one needs to measure a number of robot poses using an external measuring device. However, this process is often time-consuming, expensive and difficult for robot on-line calibration. In this paper, a methodical way of calibration of parallel robots is introduced. This method is performable only by measuring joint variable vector and positioning differences relative to a constant position in some sets of configurations that the desired positions in each set are fixed, but the moving... 

    A critical assessment of forming limit prediction models and beneficial modifications to them

    , Article SAE Technical Papers ; 2012 Ghazanfari, A ; Assempour, A ; Sharif University of Technology
    SAE  2012
    Abstract
    Major forming limit prediction models and calibration methods are reviewed briefly and their advantages and disadvantages are discussed. Two modified Marciniak-Kuczynski (M-K) models and one modified NADDRG (Keeler-Brazier) model are also presented which have some advantages over conventional models. In the first modified M-K model, material non-homogeneity has been substituted for geometrical non-homogeneity to reduce the sensitivity of the traditional model to variations of the initial non-homogeneity. Using this important advantage, a semi-empirical relation is proposed to predict the value of the initial material non-homogeneity. In the second modified M-K model, the conventional... 

    An innovative genetic algorithm approach for direct calibration of X-probe hot wires

    , Article Experimental Techniques ; Volume 36, Issue 1 , MAR , 2012 , Pages 50-60 ; 07328818 (ISSN) Manshadi, M. D ; Keshavarz, B ; Soltani, M. R ; Ghorbanian, K ; Sharif University of Technology
    2012
    Abstract
    A new genetic algorithm (GA) based method for direct calibration of 2-D hot-wire probe and other instruments that can measure 2-D flow properties is introduced. This new method is an alternative for the previous QR method that is commonly used for calibration of the X-probe hot wires. The proposed GA method resulted in a much smaller error in the velocity estimation while preserving the number of sentences in its calibration equation format. In addition, it preserves the magnitude of its error even when the number of sentences in the calibration equation is decreased while the error in the QR method increases substantially for the same situation. Furthermore, the results were much closer to... 

    A low power 1.2 GS/s 4-bit flash ADC in 0.18 μm CMOS

    , Article Proceedings of IEEE East-West Design and Test Symposium, EWDTS 2013 ; 2013 ; 9781479920969 (ISBN) Chahardori, M ; Sharifkhani, M ; Sadughi, S ; Sharif University of Technology
    2013
    Abstract
    A low power 4-bit flash ADC is proposed. A new power reduction technique is employed which deactivates the unused blocks in the converter structure in order to reduce the power consumption. A new method for built-in threshold voltage generation together with a new offset calibration method is used to further reduce the power consumption in the converter. Monte-Carlo simulation shows that after calibration both the INL and the DNL are lower than 0.35 LSB. The converter achieves 3.5 effective number of bits (ENOB) at 1.2 GS/s sampling rate after the offset calibration is performed. It consumes 10 mW from a 1.8 V supply, yielding a FoM of 560 fJ/conversion.step in a 0.18 μm standard CMOS... 

    Design of low-power temperature sensor architecture for passive UHF RFID tags

    , Article Informacije MIDEM ; Volume 45, Issue 4 , 2015 , Pages 249-259 ; 03529045 (ISSN) Karkani, M. R. G ; Kamarei, M ; Ahmady, A. F ; Sharif University of Technology
    Society for Microelectronics, Electric Components and Materials  2015
    Abstract
    A low-power wide-range CMOS temperature sensor architecture is proposed based on temperature-to-frequency conversion using supply voltage controlled sub-threshold ring oscillator. The principles of operation are investigated and proved via analytic and simulation results. Most errors are canceled out by this ratio-metric design. An inaccuracy of -0.84°C to +0.34°C occurs over a range of -40°C to 80°C after using a novel in-field digital two-point calibration. The entire sensor consumes less than 93nW to 305nW over the temperature range and can be digitally reconfigured for setting sample rate and resolution in a tradeoff  

    Correction to: pose estimation of soccer players using multiple uncalibrated cameras

    , Article Multimedia Tools and Applications ; 2018 ; 13807501 (ISSN) Afrouzian, R ; Seyedarabi, H ; Kasaei, S ; Sharif University of Technology
    Springer New York LLC  2018
    Abstract
    In the pdf version of this article, the captured corresponding author was incorrect when it is correctly presented in the online version. The correct corresponding author should be Hadi Seyedarabi. It is corrected in this correction article. © 2018, Springer Science+Business Media, LLC, part of Springer Nature  

    Correction to: Pose estimation of soccer players using multiple uncalibrated cameras (Multimedia Tools and Applications, (2016), 75, 12, (6809-6827), 10.1007/s11042-015-2611-8)

    , Article Multimedia Tools and Applications ; Volume 78, Issue 2 , 2019 , Pages 2641- ; 13807501 (ISSN) Afrouzian, R ; Seyedarabi, H ; Kasaei, S ; Sharif University of Technology
    Springer New York LLC  2019
    Abstract
    In the pdf version of this article, the captured corresponding author was incorrect when it is correctly presented in the online version. The correct corresponding author should be Hadi Seyedarabi. It is corrected in this correction article. © 2018, Springer Science+Business Media, LLC, part of Springer Nature  

    The reason of cracking in bottom gallery of SefidRud Buttress Dam and earthquake and post earthquake performance

    , Article Structural Monitoring and Maintenance ; Volume 6, Issue 2 , 2019 , Pages 103-124 ; 22886605 (ISSN) Mirzabozorg, H ; Ghaemian, M ; Roohezamin, A ; Sharif University of Technology
    Techno Press  2019
    Abstract
    Present study concerns the safety evaluation of SefidRud dam's block No. 18 regarding probable crack propagation in the foundation gallery under a MCE record. Accordingly, a 3D finite element model of the block in companion with the reservoir and the foundation is modeled. All the associated thermal and structural parameters are derived via calibration with the records of thermometers and pendulums installed inside the dam body. The origination of the cracks and their whereabouts are determined by primary thermal and static analyses and through a linear dynamic analysis the potential failure zone and their extent and level are studied. The foundation gallery is the most probable zone among... 

    Correction to: Pose estimation of soccer players using multiple uncalibrated cameras (Multimedia Tools and Applications, (2016), 75, 12, (6809-6827), 10.1007/s11042-015-2611-8)

    , Article Multimedia Tools and Applications ; Volume 78, Issue 2 , 2019 , Pages 2641- ; 13807501 (ISSN) Afrouzian, R ; Seyedarabi, H ; Kasaei, S ; Sharif University of Technology
    Springer New York LLC  2019
    Abstract
    In the pdf version of this article, the captured corresponding author was incorrect when it is correctly presented in the online version. The correct corresponding author should be Hadi Seyedarabi. It is corrected in this correction article. © 2018, Springer Science+Business Media, LLC, part of Springer Nature  

    Obtaining the effect of sewage network on groundwater quality using MT3DMS code: Case study on Bojnourd plain

    , Article Groundwater for Sustainable Development ; Volume 11 , October , 2020 Kheirandish, M ; Rahimi, H ; Kamaliardakani, M ; Salim, R ; Sharif University of Technology
    Elsevier B. V  2020
    Abstract
    Groundwater contamination is a significant problem related strongly to both the protection of the environment and the need for water. In the present study, groundwater quality was investigated in the Bojnourd watershed. The Bojnourd watershed is located in the northeast of Iran, which covers 65.5 km2 of the North Khorasan province area. There are 11 extracting wells in the region. Annual water extraction from the alluvial aquifer in the area is used for agriculture, drinking, sanitary and industrial consumptions. In this research, groundwater quantity modeling, including calibration and verification by GMS software, had been performed. In the quality modeling stage, pollution contours for... 

    Optimization-based gravity-assisted calibration and axis alignment of 9-degrees of freedom inertial measurement unit without external equipment

    , Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 234, Issue 2 , 2020 , Pages 192-207 Razavi, H ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    SAGE Publications Ltd  2020
    Abstract
    Applicable in numerous fields, low-cost micro-electromechanical system inertial measurement units often require on-sight calibration by the end user due to the existence of systematic errors. A 9-degrees of freedom inertial measurement unit comprises a tri-axis accelerometer, a tri-axis gyroscope, and a tri-axis magnetometer. Various proposed multi-position calibration methods can calibrate tri-axis accelerometers and magnetometers to a degree. Yet the full calibration of a tri-axis gyroscope and axis alignment of all the sensors still often requires equipment such as a rate table to generate a priori known angular velocities and attitudes or relies on the disturbance-prone magnetometer... 

    , M.Sc. Thesis Sharif University of Technology Javanmardi, Nasrin (Author) ; Sayyadi, Hassan (Supervisor) ; Abbaspour, Madjid (Supervisor)
    Abstract
    Now a day measuring dimensions plays an important role in industries. Improving the technology of measuring the dimensions, leads to higher quality of production. It is important for industries to have a rapid and accurate dimensions in short time. In this thesis, we worked on measuring dimensions with 3D laser scanner and in the end, the results related to accuracy and speed and efficiency of the system was shown in the thesis  

    Integrated Navigation for Attitude and Orbit Estimation of Nano satellite with Online Calibration

    , M.Sc. Thesis Sharif University of Technology Jafaripour, Masoud (Author) ; Salarieh, Hassan (Supervisor) ; Alasti, Aria (Supervisor) ; Jalili, Hadi (Co-Supervisor)
    Abstract
    In this study, integrated navigation for attitude and orbit estimation of nanosatellite with online magnetometer calibration is derived. This algorithm has been developed based on the Extended Kalman Filter and Unscented Kalman Filter and the unknown magnetometer’s parameters (such as bias vector and scale factor orthogonal matrix and non-orthognal misallignmet matrix) are estimated in order to calibration of this sensor. In order to determine the location and orientation of the satellite, many different algorithms have been developed which have the ability to determine the location without the need for GPS sensor; it is necessary to be calibrated and ensure proper performance of these...