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    Fault Detection and Identification in Robotic Systems

    , M.Sc. Thesis Sharif University of Technology Baghbahari, Masoud (Author) ; Namvar, Mehrzad (Supervisor)
    Abstract
    Fault detection and identification is one of the major issues and challenges in the field of engineering and currently is considered as an active field of research. As the replacement of human in dangerous or inaccessible environments, robotic mechanical systems can be used which exposes to a variety of stresses and actions that causes faults in the actuators or sensors. Accordingly, detection of fault at the earliest possible time after the fault accurence and its identification such that real flaw waveform is being extracted, can prevent more damage to the system without any need to human immediate interference. Model based approach in recent decades has shown their ability to detection... 

    Fault Detection in Robotic Swarm

    , M.Sc. Thesis Sharif University of Technology Mollahossein, Mojtaba (Author) ; Alasti, Aria (Supervisor) ; Salarieh, Hassan (Co-Supervisor)
    Abstract
    Fault detection in swarm robots is one of the most important issues that has drawn a lot of scientists’ attention. Previous studies have shown a lot of problems regarding this issue, such as dependency of data-based methods to mission and high complexity of model-based methods on the condition that nonlinear models are used. Extended information filter is an applicable method for fault detection because it could turn the inverse of a big matrix to a simple summation of information that is so desired in terms of calculations. The goal of this study is to identify the agents with fault in swarm robots online by modifying the extended information filter. In this study, it has been attempted to... 

    Fault detection and isolation of satellite gyroscopes using relative positions in formation flying

    , Article Aerospace Science and Technology ; Volume 78 , 2018 , Pages 403-417 ; 12709638 (ISSN) Shakouri, A ; Assadian, N ; Sharif University of Technology
    Elsevier Masson SAS  2018
    Abstract
    A fault detection and isolation method for satellite rate gyros is proposed based on using the satellite-to-satellite measurements such as relative position beside orbit parameters of the primary satellite. By finding a constant of motion, it is shown that the dynamic states in a relative motion are restricted in such a way that the angular velocity vector of primary satellite lies on a quadratic surface. This constant of motion is then used to detect the gyroscope faults and estimate the corresponding scale factor or bias values of the rate gyros of the primary satellite. The proposed algorithm works even in time variant fault situations as well, and does not impose any additional... 

    Attitude estimation and control based on modified unscented Kalman filter for gyro-less satellite with faulty sensors

    , Article Acta Astronautica ; Volume 191 , 2022 , Pages 134-147 ; 00945765 (ISSN) Pourtakdoust, S.H ; Mehrjardi, M. F ; Hajkarim, M. H ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    A modified unscented Kalman filter is presented to estimate the quaternion parameters as well as the angular velocities of a rigid gyro-less satellite under faulty sensor conditions. The task is carried out using the Sun sensor and magnetometers as attitude sensors with bounded noise and unknown fault(s). Following the presentation of the satellite attitude dynamics and filtering formulations, a new fault detection and isolation algorithm is proposed. The latter is based on a modified unscented Kalman filter structure for improved fault detection, sensor isolation, and attitude control (AC). A Backtracking Search Algorithm (BSA) is also used to design and optimize the PID controller gains,... 

    Reliability improvement of distribution systems using SSVR

    , Article ISA Transactions ; Volume 48, Issue 1 , 2009 , Pages 98-106 ; 00190578 (ISSN) Hosseini, M ; Shayanfar, H. A ; Fotuhi Firuzabad, M ; Sharif University of Technology
    2009
    Abstract
    This paper presents a reliability assessment algorithm for distribution systems using a Static Series Voltage Regulator (SSVR). Furthermore, this algorithm considers the effects of Distributed Generation (DG) units, alternative sources, system reconfiguration, load shedding and load adding on distribution system reliability indices. In this algorithm, load points are classified into 8 types and separated restoration times are considered for each class. Comparative studies are conducted to investigate the impacts of DG and alternative source unavailability on the distribution system reliability. For reliability assessment, the customer-oriented reliability indices such as SAIFI, SAIDI, CAIDI...