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    Manufacturing error compensation based on cutting tool location correction in machining processes

    , Article International Journal of Computer Integrated Manufacturing ; Vol. 27, Issue. 11 , 29 Oct , 2014 , pp. 969-978 ; ISSN: 0951192X Khodaygan, S ; Sharif University of Technology
    Abstract
    Inaccuracies in workpiece location lead to errors in position and orientation of machined features on the workpiece, and strongly affect the assemblability and the quality of the product. The accurate positioning of workpiece on a fixture is influenced by rigid body displacements and rotations of the workpiece due to several errors (e.g. geometric radial and position errors in locators and manufacturing tolerances of the workpiece). In this paper, an efficient approach is introduced for analysis and compensation errors in the workpiece-fixture-cutting tool system. A new mathematical formulation of workpiece-fixture modelling is proposed to establish the relationship between the locating... 

    Improvement of robot navigation using fuzzy method

    , Article 2013 3rd Joint Conference of AI and Robotics and 5th RoboCup Iran Open International Symposium: Learning, Glorious Future ; 2013 , pp.1-5 ; 9781467363150 (ISBN) Nazari, M ; Amiryan, J ; Nazemi, E ; Sharif University of Technology
    2013
    Abstract
    In this paper a technique for autonomous navigation of mobile robots is presented. The most important advantage of this method is to ignore the physical model of the robot and that the robot model is considered as an unknown but predictable system. This approach can be executed in environments which robot navigation is done using global sensors e.g. a camera installed in the environment to sense and control the robot and also every feedback system which is able to measure the velocity of the robot can be used for this technique. In this approach, the well-known fuzzy method, Takagi-Sugeno, has been applied to estimate the dynamic model of robot. Our technique has been applied successfully in... 

    How to synchronize and register an optical-inertial tracking system

    , Article Applied Mechanics and Materials ; Volume 332 , 2013 , Pages 130-136 ; 16609336 (ISSN) ; 9783037857335 (ISBN) Soroush, A ; Akbar, M ; Farahmand, F ; Sharif University of Technology
    2013
    Abstract
    Multi-sensor tracking is widely used for augmentation of tracking accuracy using data fusion. A basic requirement for such applications is the real time temporal synchronization and spatial registration of two sensory data. In this study a new method for time and space coordination of two tracking sensor measurements has been presented. For spatial registration we used a body coordinate system and then applied the effect of the level arm. The time synchronization was done based on least mean square (LMS) error method. This method was implemented to synchronize the position and orientation of an object using Inertial (1IMU) and Optical (Optotrak) tracking systems. The results of synchronized... 

    An efficient method for workpiece locating error prediction in machining process

    , Article SAE 2016 World Congress and Exhibition, 12 April 2016 through 14 April 2016 ; Volume 2016-April , April , 2016 Khodaygan, S ; Sharif University of Technology
    SAE International 
    Abstract
    Fixtures play a key role in locating workpieces to manufacture high quality products within many processes of the product lifecycle. Inaccuracies in workpiece location lead to errors in position and orientation of machined features on the workpiece, and strongly affect the assemblability and the final quality of the product. The accurate positioning of workpiece on a fixture is influenced by rigid body displacements and rotations of the workpiece. In this paper, a systematic approach is introduced to investigate the located workpiece position errors. A new mathematical formulation of fixture locators modeling is proposed to establish the relationship between the workpiece position error and... 

    Dielectrophoretic interaction of two particles in a uniform electric field

    , Article Microsystem Technologies ; Volume 25, Issue 7 , 2019 , Pages 2699-2711 ; 09467076 (ISSN) Javidi, R ; Moghimi Zand, M ; Dastani, K ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    The local electric field distorsion induced by a dielectric particle leads to particle–particle interactions and assembly which is very interesting for their useful applications on microfluidic devices. Particles behavior becomes more complicated if several particles interact at the same time. This paper presents a comprehensive numerical analysis of the assembly and particle–particle interactions for two similar and dissimilar dielectric particles immersed in a dielectric fluid using the immersed interface method based on two-dimensional direct-current dielectrophoresis. The immersed interface method is a finite-difference (or finite element) based numerical method which its key advantage... 

    Model-Aided real-time localization and parameter identification of a magnetic endoscopic capsule using extended kalman filter

    , Article IEEE Sensors Journal ; Volume 21, Issue 12 , 2021 , Pages 13667-13675 ; 1530437X (ISSN) Sadeghi Boroujeni, P ; Nejat Pishkenari, H ; Moradi, H ; Vossoughi, G ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    Capsule endoscopy is a minimally invasive diagnostic technology for gastrointestinal diseases providing images from the human's digestion system. Developing a robust and real-time localization algorithm to determine the orientation and position of the endoscopic capsule is a crucial step toward medical diagnostics. In this paper, we propose a novel model-aided real-time localization approach to estimate the position and orientation of a magnetic endoscopic capsule swimming inside the stomach. In the proposed method, the governing equations of the motion of an ellipsoidal capsule inside the fluid, considering different hydrodynamics interactions, are derived. Then, based on the dynamic model,... 

    Effect of microstructure on crack behavior in nanocrystalline nickel using molecular dynamics simulation

    , Article Theoretical and Applied Fracture Mechanics ; Volume 104 , 2019 ; 01678442 (ISSN) Moradi, M ; Farrahi, G. H ; Chamani, M ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    The crack growth process in columnar nanocrystalline samples is simulated using the molecular dynamics method. The effects of grain size, grain boundary, crystallographic orientation and crack tip position on the crack growth behavior are investigated. Different sets of samples with mean grain sizes ranging from 4 nm to 14 nm are prepared. Samples with a similar number of grains and identical dimensions are considered for examining the impact of grain boundary and crystallographic orientation. To assess the effect of the grain boundary, no constraint is considered on the position and orientation of grains, while only the grain orientations are changed to examine the effect of... 

    Accuracy improvement of GPS/INS navigation system using extended kalman filter

    , Article 6th International Conference on Control, Instrumentation and Automation, ICCIA 2019, 30 October 2019 through 31 October 2019 ; 2019 ; 9781728158150 (ISBN) Abbasi, P ; Haeri, M ; Iranian Society of Instrumentation and Control Engineers; Smart/Micro Grids Research Center; University of Kurdistan ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Inertial navigation is a method for determining position and orientation of a vehicle, which operates according to Newton's laws of motion. Due to continual increase of output error because of measurement noise, bias, misalignment and so on, one may need one or more additional navigation systems to improve accuracy in long-Term navigation. In this paper, the error compensation based on GPS/INS data fusion algorithm is studied. Then, by designing a DSP processor-based hardware, GPS and INS data are recorded and GPS/INS data fusion algorithm is implemented. Results indicate that the accuracy of the positioning is improved and position, velocity, and orientation errors are confined to a limited... 

    Investigation of a hybrid kinematic calibration method for the 'sina' surgical robot

    , Article IEEE Robotics and Automation Letters ; Volume 5, Issue 4 , 2020 , Pages 5276-5282 Alamdar, A ; Samandi, P ; Hanifeh, S ; Kheradmand, P ; Mirbagheri, A. R ; Farahmand, F ; Sarkar, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Calibrating the inverse kinematics of complex robots is often a challenging task. Finding analytical solutions is not always possible and the convergence of numerical methods is not guaranteed. The model-free approaches, based on machine learning and artificial intelligence, are fast and easy to work, however, they need a huge amount of experimental training data to provide acceptable results. In this article, we proposed a hybrid method to benefit the advantage of both model-based and model-free approaches. The forward kinematics of the robot is calibrated using a model-based approach, and its inverse kinematics using a neural network. Hence, while there is no need to solve the nonlinear...