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fault-detection
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Fault Detection in Robotic Swarm
, M.Sc. Thesis Sharif University of Technology ; 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...
Improvement of Inverter-based AC Microgrids Protection Against Short Circuit
, Ph.D. Dissertation Sharif University of Technology ; Mokhtari, Hossein (Supervisor) ; Blaabjerg, Frede (Co-Supervisor)
Abstract
Inverter-based distributed generations (IBDGs) have gained special interest in the electricity supply chain due to the advancements in power electronics technology. Power electronic inverters provide high-efficiency energy conversion with full controllability over a wide operating range, and ancillary services such as reactive power support and active filtering. Considering the voltage and frequency control capability of power inverters, supplying inverter-based micro-grid (IBMG) loads is now pissible. Despite the significant opportunities associated with such sources, they introduce new challenges that should be addressed properly. Reliable and accurate protection against short circuit...
Fault diagnosis within multistage machining processes using linear discriminant analysis: a case study in automotive industry
, Article Quality Technology and Quantitative Management ; Volume 14, Issue 2 , 2017 , Pages 129-141 ; 16843703 (ISSN) ; Baradaran Kazemzadeh, R ; Akhavan Niaki, S. T ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
Statistical process control provides useful tools to improve the quality of multistage machining processes, specifically in continuous manufacturing lines, where product characteristics are measured at the final station. In order to reduce process errors, variation source identification has been widely applied in machining processes. Although statistical estimation and pattern matching-based methods have been utilized to monitor and diagnose machining processes, most of these methods focus on stage-by-stage inspection using complex models and patterns. However, because of the existence of high rate alarms and the complexity of the machining processes, a surrogate modelling is needed to solve...
A unified framework for passive–active fault-tolerant control systems considering actuator saturation and L ∞ disturbances
, Article International Journal of Control ; Volume 92, Issue 3 , 2019 , Pages 653-663 ; 00207179 (ISSN) ; Haeri, M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
This paper presents a unified passive–active fault-tolerant control strategy to compensate the loss of actuators’ effectiveness. The proposed approach is capable of handling the system in pre- and post-fault diagnosis intervals by passive and active approaches, respectively. The stability of the designed system is independent of the accuracy of information provided by the fault detection and diagnosis unit, however, a precise estimation could improve the conservation. Actuator saturation and L ∞ disturbances effects are considered in the design stage. The trade-off between maximising the domain of attraction and minimising the effects of L ∞ disturbances is tackled by developing a...
Switch level fault emulation
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 2778 , 2003 , Pages 849-858 ; 03029743 (ISSN); 3540408223 (ISBN); 9783540408222 (ISBN) ; Ejlali, A ; Sharif University of Technology
Springer Verlag
2003
Abstract
The switch level is an abstraction level between the gate level and the electrical level, offers many advantages. Switch level simulators can reliably model many important phenomena in CMOS circuits, such as bi-directional signal propagation, charge sharing and variations in driving strength. However, the fault simulation of switch level models is more time-consuming than gate level models. This paper presents a method for fast fault emulation of switch level circuits using FPGA chips. In this method, gates model switch level circuits and we can emulate mixed gate-switch level models. By the use of this method, FPGA chips can be used to accelerate the fault injection campaigns into switch...
A unified approach to detect and distinguish hardware trojans and faults in sram-based fpgas
, Article Journal of Electronic Testing: Theory and Applications (JETTA) ; Volume 35, Issue 2 , 2019 , Pages 201-214 ; 09238174 (ISSN) ; Bayat Sarmadi, S ; Pooyan, F ; Asadi, H ; Sharif University of Technology
Springer New York LLC
2019
Abstract
In recent years, confrontation with hardware Trojans has become a major concern due to various reasons including outsourcing. Such a growing threat is more pronounced in reconfigurable devices as they are used in widespread applications due to low design cost and short time-to-market. Besides their vulnerability to hardware Trojan attacks, SRAM-based reconfigurable devices are also significantly susceptible to faults originated by particle strikes. There have been various methods to mitigate either hardware Trojan attacks or faults. To our knowledge, however, no method has been presented that can integrate detecting, distinguishing, and mitigating faults and Trojans. In this paper, we...
Online identification of aircraft dynamics in the presence of actuator faults
, Article Journal of Intelligent and Robotic Systems: Theory and Applications ; Volume 96, Issue 3-4 , 2019 , Pages 541-553 ; 09210296 (ISSN) ; Banazadeh, A ; Sharif University of Technology
Springer
2019
Abstract
In this paper, a multiple model-based nonlinear identification approach is introduced for a conventional aircraft in the presence of different types of actuator faults. Occurrence of actuator faults can obviously reduce the validity of a predetermined dynamic model of nonlinear systems. In such cases, use of multi-model structures can be an effective choice. However, determining the optimal validity functions of the local models in a multi-model structure is still a challenging problem. This problem becomes even more challenging in case of unpredictable faults, which are not considered in training the local models. In this paper, two effective techniques are proposed for online determination...
Fast detection of open-switch fault in cascaded H-bridge multilevel converter
, Article Scientia Iranica ; Volume 25, Issue 3D , 2018 , Pages 1561-1570 ; 10263098 (ISSN) ; Zolghadri, M. R ; Khodabandeh, M ; Ouni, S ; Sharif University of Technology
Sharif University of Technology
2018
Abstract
Cascaded H-bridge converter has been utilized recently in different high-power applications due to its modular and simple structure. In order to have a balanced operation after a fault occurrence in this converter, it is necessary to detect the switch fault and its location. In this paper, a fast power-switch fault detection method is presented to identify a fault and its location. Only one voltage measurement per phase is required by this method, and the fault detection is faster compared to the existing methods. Moreover, it is suitable for implementation on an FPGA device due to the use of simple math, relational, and state machine blocks. The proposed method is verified by computer...
Detection of inappropriate working conditions for the timing belt in internal-combustion engines using vibration signals and data mining
, Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 231, Issue 3 , 2017 , Pages 418-432 ; 09544070 (ISSN) ; Banakar, A ; Ghobadian, B ; Agha Mirsalim, M ; Minaei, S ; Jafari, S. M ; Sharif University of Technology
SAGE Publications Ltd
2017
Abstract
Abnormal operating conditions for the timing belt can lead to cracks, fatigue, sudden rupture and damage to engines. In this study, an intelligent system was developed to detect and classify high-load operating conditions and high-temperature operating conditions for timing belts. To achieve this, vibration signals in normal operating conditions, high-load operating conditions and high-temperature operating conditions were collected. Time-domain signals were transformed to the frequency domain and the time-frequency domain using the fast Fourier transform method and the wavelet transform method respectively. In the data-mining stage, 25 statistical features were extracted from different...
Inaccessible rolling bearing diagnosis using a novel criterion for Morlet wavelet optimization
, Article JVC/Journal of Vibration and Control ; Volume 28, Issue 11-12 , 2022 , Pages 1239-1250 ; 10775463 (ISSN) ; Kiakojouri, A ; Arghand, H. A ; Davoodabadi, A ; Sharif University of Technology
SAGE Publications Inc
2022
Abstract
The objective of this research is to diagnose an inaccessible rolling bearing by indirect vibration measurement. In this study, a shaft supported with several bearings is considered. It is assumed that the vibration for at least one bearing is not recordable. The purpose is to diagnose inaccessible bearing by the recorded data from the sensors located on the other bearings. To achieve this goal, the continuous wavelet transform is used to detect weak signatures in the available vibration signals. A new criterion for adjusting the scale parameter of continuous wavelet transform is proposed based on the amplitude of the bearing characteristic frequencies. In this criterion, the optimal scale...
Sliding Mode Observers to Detect and Isolate Faults in a Turbocharged Gasoline Engine
, Article SAE International Journal of Engines ; Volume 8, Issue 2 , April , 2015 , Pages 399-410 ; 19463936 (ISSN) ; Alasty, A ; Vossoughi, G. R ; Sharif University of Technology
SAE International
2015
Abstract
This paper presents a novel model-based algorithm which is able to detect and isolate major faults assigned to the gas exchange path of a gasoline engine both in the intake and exhaust sides. The diagnostics system is developed for detection and isolation of these faults: air leakage fault between the compressor and the air throttle, exhaust manifold pressure sensor fault, wastegate stuck-closed fault and wastegate stuck-open fault. Sliding mode observers (SMOs) are the core detection algorithms utilized in this work. A first order SMO is designed to estimate the turbocharger rotational dynamics. The wastegate displacement dynamics coupled to the exhaust manifold pressure dynamics is...
Experimental study of rolling element bearing failure pattern based on vibration growth process
, Article Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019, 22 September 2019 through 26 September 2019 ; 2020 , Pages 1179-1186 ; Behzad, M ; Ghodrati, B ; Taghizadeh Vahed, A ; Sharif University of Technology
Research Publishing Services
2020
Abstract
Rolling-element bearing (REB) Failure is one of the most common failure in rotary machines in industry. Therefore, this concern draws attention to the concept of diagnostic and the prediction of REB failure. The efficacy of vibration analysis in this area has led many researchers to focus on this topic in recent decades. Defective bearings such as fatigue, surface roughness, and corrosion can lead to disastrous accidents. Therefore, providing an algorithm for the detection and classification of bearing defects is valuable and useful. The prediction of the bearing's lifetime is important to ensure the planned production in an industrial unit. In this paper, different models for performance...
Quick diagnosis of short circuit faults in cascaded H-bridge multilevel inverters using FPGA
, Article Journal of Power Electronics ; Volume 17, Issue 1 , 2017 , Pages 56-66 ; 15982092 (ISSN) ; Zolghadri, M. R ; Rodriguez, J ; Shahbazi, M ; Oraee, H ; Lezana, P ; Schmeisser, A. U ; Sharif University of Technology
Korean Institute of Power Electronics
2017
Abstract
Fast and accurate fault detection is the primary step and one of the most important tasks in fault tolerant converters. In this paper, a fast and simple method is proposed to detect and diagnosis the faulty cell in a cascaded H-bridge multilevel inverter under a short circuit fault. In this method, the reference voltage is calculated using switching control pulses and DC-Link voltages. The comparison result of the output voltage and the reference voltage is used in conjunction with active cell pulses to detect the faulty cell. To achieve this goal, the cell which is active when the Fault signal turns to “0” is detected as the faulty cell. Furthermore, consideration of generating the active...
Actuator failure-tolerant control of an all-thruster satellite in coupled translational and rotational motion using neural networks
, Article International Journal of Adaptive Control and Signal Processing ; 2018 ; 08906327 (ISSN) ; Assadian, N ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
The nonlinear model predictive control (MPC) approach is used to control the coupled translational-rotational motion of an all-thruster spacecraft when one of the actuators fails. In order to model the dynamical response of the spacecraft in MPC, instead of direct integration, a neural network (NN) model is utilized. This model is built of a static NN, followed by a dynamic NN. The static NN is used to find the changes of the mapping of “the demanded forces to the thrusters” and “the real torques/forces produced by the remaining thrusters” after the failure occurrence through online training. In this manner, the effect of failed thruster on the dynamics can be found and the need for...
Fast fault detection method for modular multilevel converter semiconductor power switches
, Article IET Power Electronics ; Volume 9, Issue 2 , 2016 , Pages 165-174 ; 17554535 (ISSN) ; Khodabandeh, M ; Zolghadri, M. R ; Sharif University of Technology
Institution of Engineering and Technology
2016
Abstract
This study proposes a new fault detection method for modular multilevel converter (MMC) semiconductor power switches. While in common MMCs, the cells capacitor voltages are measured directly for control purposes, in this study voltage measurement point changes to the cell output terminal improving fault diagnosis ability. Based on this measurement reconfiguration, a novel fault detection algorithm is designed for MMCs semiconductor power switches. The open circuit and short circuit faults are detected based on unconformity between modules output voltage and switching signals. Simulation and experimental results confirm accurate and fast operation of the proposed method in faulty cell...
A Second-Order Sliding Mode Observer for Fault Detection and Isolation of Turbocharged SI Engines
, Article IEEE Transactions on Industrial Electronics ; Volume 62, Issue 12 , June , 2015 , Pages 7795-7803 ; 02780046 (ISSN) ; Vossoughi, G ; Alasty, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper proposes a novel method for detection and isolation of wastegate (WG) faults in a turbocharged (TC) gasoline engine. This paper starts with a fault effect analysis on the WG faults, including WG stuck open and stuck closed, which is an early step in a detection strategy design. Then, a second-order sliding-mode observer (SOSMO) is proposed to capture the exhaust manifold dynamics. The observer uses experimentally validated engine models to estimate the WG position and a virtual force. The virtual force represents the external disturbances that disrupt the WG operation and enables the proposed SOSMO to estimate the WG position robust to the faults. Using this force, a detection and...
Functional observer design with application to pre-compensated multi-variable systems
, Article 2015 IEEE Conference on Control and Applications, CCA 2015 - Proceedings, 21 September 2015 through 23 September 2015 ; 2015 , Pages 620-625 ; 9781479977871 (ISBN) ; Mohajerpoor, R ; Abdi, H ; Nahavandi, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Partial state estimation of dynamical systems provides significant advantages in practical applications. Likewise, pre-compensator design for multi variable systems invokes considerable increase in the order of the original system. Hence, applying functional observer to pre-compensated systems can result in lower computational costs and more practicability in some applications such as fault diagnosis and output feedback control of these systems. In this note, functional observer design is investigated for pre-compensated systems. A lower order pre-compensator is designed based on a H2 norm optimization that is designed as the solution of a set of linear matrix inequalities (LMIs). Next, a...
Performance improvement of steady-state and transient operation of offshore wind farm HVDC power transmission
, Article 2015 IEEE 16th Workshop on Control and Modeling for Power Electronics, COMPEL 2015, 12 July 2015 through 15 July 2015 ; July , 2015 , Page(s): 1 - 7 ; 9781467368476 (ISBN) ; Ebrahimi, S ; Parniani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Wind power generation is increasing fast as a clean renewable energy resource. Offshore wind farms are popular due to advantages such as higher and smoother wind speeds, less farm site limitations, etc. High capacitive currents and need to expensive compensations, make use of high-voltage-direct-current (HVDC) power transmission indispensable for longdistance wind farm power generations. Steady-state and transient performance improvements of HVDC systems have always been an interesting industrial and academic research area. In this paper, a novel control method is proposed to improve the steady-state operation of HVDC system. Moreover, a new fault detection scheme is proposed to improve the...
Fault detection of wind turbine blade under sudden change of wind speed condition using fiber optics
, Article SAS 2015 - 2015 IEEE Sensors Applications Symposium, Proceedings, 13 April 2015 through 15 April 2015 ; April , 2015 ; 9781479961160 (ISBN) ; Entesari, F ; Alimohmmadi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper a structural health monitoring technique considering the effect of wind on structural stability on laminated composite wind turbine has been investigated. Based on fluid structure interaction method and Has hin failure criteria, condition monitoring of w ind turbine blades under sudden change of wind speed is investigated. The embedded fiber optic sensors are considered to detect the change in strain due to wind forces on the blades
Fast detection of open-switch fault in cascaded H-Bridge multilevel converter
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; February , 2015 , Pages 538-543 ; 9781479976539 (ISBN) ; Zolghadri, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Cascaded H-Bridge converter has recently been utilized in different high-power applications due to its modular and simple structure. In order to have a balanced operation after a fault occurrence in this converter, it is necessary to detect the switch fault and its location. In this paper, a fast power switch fault detection method is presented to identify the fault and its location. Only one voltage measurement per phase is required by this method, and the fault detection is faster compared to the existing methods. Moreover, it is easy for implementation on an FPGA device, due to the use of simple math, relational and state machine blocks. The proposed method is verified by computer...