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parameter-uncertainty
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H∞ control of a flexible transmission system
, Article Proceedings of the Thirty-Sixth Southeastern Symposium on System Theory (SSST04), Atlanta, GA., 14 March 2004 through 16 March 2004 ; Volume 36 , 2004 , Pages 536-540 ; Sadati, N ; Sharif University of Technology
2004
Abstract
An application of a continuous-time H∞ control to a flexible transmission system is presented. This approach has been proposed in order to assure high control performance in the presence of large load variation on the system. In this approach, the loading variations are considered as the multiplicative perturbation of the nominal plant. The desired specifications are enforced in the H∞ problem as the constraints on weighting functions. After an initial design procedure, the parameters of weighting functions, in order to obtain the desired performances, are tuned and then the final weighting functions are derived. The simulation results for three different loadings are given and compared
Design and Comparison of an Adaptive and Robust Control Strategy to Improve the Boiler-Turbine unit Performance and Reduction of Make-Up Water
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor) ; Vossoughi, Gholamreza (Supervisor)
Abstract
There is many sources of uncertainty in the power plants such as continuous changes of the ambient temperature and the climate condition. The controller of the boiler-turbine unite should be robust against uncertainties and overcome the changes in the operating condition. In this regard, a robust adaptive variable structure control scheme (RAVCS) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler-turbine unite, in the presence of unknown parameters and bounded uncertainties as well as external disturbances. Moreover, a robust controller based on and in the presence of rational deviation in parameters, is designed. To investigate the zero...
Forecasting the effects of a Canada-US currency union on output and prices: A counterfactual analysis
, Article Journal of Forecasting ; Volume 32, Issue 7 , 2013 , Pages 639-653 ; 02776693 (ISSN) ; Sharif University of Technology
2013
Abstract
This paper is a counterfactual analysis investigating the consequences of the formation of a currency union for Canada and the USA: whether outputs increase and prices decrease if these countries form a currency union. We use a two-country cointegrated model to conduct the counterfactual analysis, where the conditional forecasts are generated based on the Gaussian assumption. To deal with structural breaks and model uncertainty, conditional forecasts are generated from different models/estimation windows and the model-averaging technique is used to combine the forecasts. We also examine the robustness of our results to parameter uncertainty using the wild bootstrap method. The results show...
Adaptive observer-based synchronization of two non-identical chaotic systems with unknown parameters
, Article JVC/Journal of Vibration and Control ; Volume 23, Issue 3 , 2017 , Pages 389-399 ; 10775463 (ISSN) ; Shahrokhi, M ; Salarieh, H ; Sharif University of Technology
SAGE Publications Inc
2017
Abstract
In this study, adaptive observer-based synchronization of chaotic systems is considered. The master and slaves systems have different dynamics and it is assumed that the master system parameters are unknown while its states are available. First, it is assumed that the slave system parameters are known but its states are not completely available. It is shown that an observer for the slave system can be designed and applied for the purpose of synchronization. Based on a Lyapunov function, an adaptive law for master parameters estimation and a control law for the synchronization goal are extracted. Stability of the entire system including the observer dynamics has been proved. Further, it is...
Design & application of adaptive variable structure & H∞ robust optimal schemes in nonlinear control of boiler-turbine unit in the presence of various uncertainties
, Article Energy ; Volume 142 , 2018 , Pages 1040-1056 ; 03605442 (ISSN) ; Moradi, H ; Vossoughi, G ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this article, to improve the precision, performance and robustness of an industrial boiler-turbine, two robust controllers are designed. First, a robust adaptive variable structure control scheme (RAVSC) is proposed to control a nonlinear multi-inputs multi-outputs (MIMO) model of an industrial boiler-turbine unit, in the presence of significant uncertainties and external disturbances. To guarantee the reliable performance of the RAVSC, appropriate adaption and control laws are introduced to compensate the uncertainties and modeling imprecisions and guarantee the convergence to the sliding surface. Then, the robustness and stability of the proposed RAVSC is proved via Lyapunov stability...
Prediction-based Control for Mitigation of Axial-torsional Vibrations In a Distributed Drill-String System in the Presence of Parametric Uncertainties
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor) ; Zohoor, Hassan (Supervisor)
Abstract
Drill strings are subjected to complex coupled dynamics. Therefore, accurate dynamic modeling, which can represent the physical behavior of real drill strings, is of great importance for system analysis and control. The most widely used dynamic models for such systems are the lumped element models which neglect the system distributed feature. In this thesis, an infinite-dimensional model for the vibrational dynamics of the drill-string, called neutral-type time delay model, is modified to investigate the coupled axial-torsional vibrations in drill strings. This model is derived directly from the distributed parameter model by employing the d’Alembert method. Coupling of axial and torsional...
Robust optimization approach for an aggregate production–distribution planning in a three-level supply chain
, Article International Journal of Advanced Manufacturing Technology ; Vol. 76, issue. 1-4 , 2014 , p. 623-634 ; Niaki, S. T. A ; Pasandideh, S. H. R ; Sharif University of Technology
Abstract
An aggregate production–distribution (P-D) planning generates an aggregate plan for regular time, overtime, outsourcing, hiring, and firing that takes into account distributing, inventory holding, backordering, and machine capacity for a definite planning horizon. A large number of P-D problems require decisions to be made in the presence of uncertainty. Previous research on this topic mainly utilized either stochastic programming or fuzzy programming to cope with the uncertainty. This may lead into huge challenges for supply chain managers that use non-robust P-D planning in uncertain environments. Moreover, there has been little discussion about robust optimization approach in aggregate...
Non-fragile control and synchronization of a new fractional order chaotic system
, Article Applied Mathematics and Computation ; Volume 222 , 2013 , Pages 712-721 ; 00963003 (ISSN) ; Delshad, S. S ; Hamidi Beheshti, M. T ; Tavazoei, M. S ; Sharif University of Technology
2013
Abstract
In this paper, we address global non-fragile control and synchronization of a new fractional order chaotic system. First we inspect the chaotic behavior of the fractional order system under study and also find the lowest order (2.49) for the introduced dynamics to remain chaotic. Then, a necessary and sufficient condition which can be easily extended to other fractional-order systems is proposed in terms of Linear Matrix Inequality (LMI) to check whether the candidate state feedback controller with parameter uncertainty can guarantee zero convergence of error or not. In addition, the proposed method provides a global zero attraction of error that guarantees stability around all existing...
Application of particle swarm optimization in chaos synchronization in noisy environment in presence of unknown parameter uncertainty
, Article Communications in Nonlinear Science and Numerical Simulation ; Volume 17, Issue 2 , 2012 , Pages 742-753 ; 10075704 (ISSN) ; Vatankhah, R ; Boroushaki, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Abstract
In this paper, particle swarm optimization (PSO) is applied to synchronize chaotic systems in presence of parameter uncertainties and measurement noise. Particle swarm optimization is an evolutionary algorithm which is introduced by Kennedy and Eberhart. This algorithm is inspired by birds flocking. Optimization algorithms can be applied to control by defining an appropriate cost function that guarantees stability of system. In presence of environment noise and parameter uncertainty, robustness plays a crucial role in succeed of controller. Since PSO needs only rudimentary information about the system, it can be a suitable algorithm for this case. Simulation results confirm that the proposed...
Adaptive robust synchronization of chaotic systems using particle swarm optimization based controller
, Article Program and Abstract Book - 2010 7th International Conference on Electrical Engineering, Computing Science and Automatic Control, CCE 2010, 8 September 2010 through 10 September 2010 ; September , 2010 , Pages 54-59 ; 9781424473120 (ISBN) ; Vatankhah, R ; Boroushaki, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Abstract
In this paper, a robust control design strategy is introduced to synchronize two different chaotic systems. The controller is based on particle swarm optimization (PSO). Particle swarm optimization is a well-known evolutionary optimization algorithm inspired by organism behavior of birds flocking and fish schooling. Our control approach is based on defining a suitable cost function in such a way that minimizing it guarantees the control of system. Due to the nature of PSO algorithm, the designed controller is strongly robust. It is shown that the proposed controller can overcome the parameter uncertainty without any extra information about the system. Comparison of proposed method with...
Robust fractional-order compensation in the presence of uncertainty in a pole/zero of the plant
, Article IEEE Transactions on Control Systems Technology ; Volume 26, Issue 3 , May , 2018 , Pages 797-812 ; 10636536 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
This paper deals with robust frequency compensation in control of fractional-order plants with an uncertain fractional pole/zero (or specially in control of integer-order plants with an uncertain pole/zero). The specifications yielding a robust compensation are introduced, and fractional-order compensators are proposed for satisfying these specifications in the set-point tracking control of the above-mentioned plants. Also, the infinite ranges for the uncertain parameter of the plant, in which satisfying robust compensation specifications is possible by the obtained compensators, are exactly specified. Furthermore, the stability of the obtained control system is analytically analyzed....
Predicting probabilistic distribution functions of response parameters using the endurance time method
, Article Structural Design of Tall and Special Buildings ; Volume 28, Issue 1 , 2019 ; 15417794 (ISSN) ; Mirfarhadi, S. A ; E. Estekanchi, H ; Vafai, H ; Sharif University of Technology
John Wiley and Sons Ltd
2019
Abstract
The main objective of this study is the development of endurance time (ET) excitations in order to take structural response uncertainty into account for use in performance-based earthquake engineering. There are several uncertainties in earthquake engineering, including earthquake occurrence, structural response, damage, and loss. In the current research, structural response uncertainty is directly included in the ET method, which is an analysis method used for performing structural behavior assessment under seismic actions. Conventional practice of the ET method does not provide any information about seismic response distribution. Despite the simplicity of the ET method, it is an accurate...
Model reference adaptive control of SUT building energy management system
, Article 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, 5 November 2005 through 11 November 2005 ; Volume 10 , 2006 , Pages 25-28 ; 0791842274 (ISBN) ; Selk Ghafari, A ; Hannani, S. K ; Sharif University of Technology
2006
Abstract
Model Reference Adaptive Controller (MRAC) design, for Sharif University of Technology (SUT) Building Energy Management System (BEMS) is addressed in this paper. A reference model with fuzzy adaptive control rules was employed to design the controller for a system with time delay and model parameter uncertainties. Simulation study shows good performance of the closed loop system with optimum energy consumption for this system under external load disturbance. Copyright © 2005 by ASME
Parameter estimation and interval type-2 fuzzy sliding mode control of a z-axis MEMS gyroscope
, Article ISA Transactions ; Vol. 52, Issue 6 , 2013 , pp. 900-911 ; Pedram, M. Z ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Abstract
This paper reports a hybrid intelligent controller for application in single axis MEMS vibratory gyroscopes. First, unknown parameters of a micro gyroscope including unknown time varying angular velocity are estimated online via normalized continuous time least mean squares algorithm. Then, an additional interval type-2 fuzzy sliding mode control is incorporated in order to match the resonant frequencies and to compensate for undesired mechanical couplings. The main advantage of this control strategy is its robustness to parameters uncertainty, external disturbance and measurement noise. Consistent estimation of parameters is guaranteed and stability of the closed-loop system is proved via...
Stabilizing periodic orbits of chaotic systems using adaptive critic-based neurofuzzy controller
, Article Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference 2009, DETC2009 ; Vol. 4, Issue. PART C , 2009 , pp. 1759-1767 ; ISBN: 9780791849019 ; Vatankhah, R ; Salarieh, H ; Boroushaki, M ; Alasty, A ; Sharif University of Technology
Abstract
In this paper design and evaluation of an adaptive critic- based neurofuzzy controller for the stabilizing periodic orbits of chaotic systems has been presented in detail. The main superiority of the proposed controller over previous analogous fuzzy logic controller design approaches, e.g., genetic fuzzy logic controller, is its online tuning characteristic and remarkable reduced amount of computations used for parameter adaptation, which makes it desirable for real time applications. Considering the simplicity of this controller and its independence from the system model, this control method has the advantage of online learning and control, and can be applied to a large variety of systems....
Parameter estimation and interval type-2 fuzzy sliding mode control of a z-axis MEMS gyroscope
, Article ISA Transactions ; Volume 52, Issue 6 , 2013 , Pages 900-911 ; 00190578 (ISSN) ; Pedram, M. Z ; Salarieh, H ; Alasty, A ; Sharif University of Technology
2013
Abstract
This paper reports a hybrid intelligent controller for application in single axis MEMS vibratory gyroscopes. First, unknown parameters of a micro gyroscope including unknown time varying angular velocity are estimated online via normalized continuous time least mean squares algorithm. Then, an additional interval type-2 fuzzy sliding mode control is incorporated in order to match the resonant frequencies and to compensate for undesired mechanical couplings. The main advantage of this control strategy is its robustness to parameters uncertainty, external disturbance and measurement noise. Consistent estimation of parameters is guaranteed and stability of the closed-loop system is proved via...
Application of multi-criterion robust optimization in water-flooding of oil reservoir
, Article Journal of Petroleum Science and Engineering ; Volume 109 , September , 2013 , Pages 1-11 ; 09204105 (ISSN) ; Pishvaie, M. R ; Khorasheh, F ; Salahshoor, K ; Kharrat, R ; Sharif University of Technology
2013
Abstract
Most of the reported robust and non-robust optimization works are formulated based on a single-objective optimization, commonly in terms of net present value. However, variation of economical parameters such as oil price and costs forces such high computational optimization works to regenerate their optimum water injection policies. Furthermore, dynamic optimization strategies of water-flooding often lack robustness to geological uncertainties. This paper presents a multi-objective while robust optimization methodology by incorporating three dedicated objective functions. The goal is to determine optimized and robust water injection policies for all injection wells. It focuses on reducing...
Impacts of plug-in hybrid electric vehicle uncertainty and grid unavailability on home load management
, Article 2012 11th International Conference on Environment and Electrical Engineering, EEEIC 2012, Venice, 18 May 2012 through 25 May 2012 ; 2012 , Pages 693-698 ; 9781457718281 (ISBN) ; Safdarian, A ; Fotuhi-Firuzabad, M ; Aminifar, F ; Sharif University of Technology
IEEE
2012
Abstract
A massive focus has recently been made on demand response (DR) programs, aimed to the electricity price reduction, reliability improvement, and energy efficiency. Basically, DR programs are divided into twofold main categories, namely incentive-based programs and price- or time-based programs. The focus of this paper is on priced-based DR programs including consumer responses to the time differentiated pricing. Home load management (HLM) program is designed to control responsive appliances and charging/discharging cycles of plug-in hybrid electric vehicles (PHEVs) by the consumer. Uncertain parameters associated with PHEV, i.e. its departure/travelling time and energy consumption as well as...
Control of lumbar spine flexion-extension movement by PD controller and feedback linearization method
, Article ICCAS 2010 - International Conference on Control, Automation and Systems, 27 October 2010 through 30 October 2010 ; 2010 , Pages 2024-2029 ; 9781424474530 (ISBN) ; Vossughi, G. R ; Parnianpour, M ; Sharif University of Technology
Abstract
The role of motor control in development of low back pain is subject of many researches both in theoretical and experimental fields. In this work flexion-extension movement of lumbar spine have been controlled by three different methods, including feedback linearization (FBL), PD control and their combinations. The model involves 7 links: 1 link for pelvis, 5 links for lumbar vertebrae and 1 link for trunk. Torque actuators have been used on each joint to make them follow desired trajectory. In linear control method, equations of motion have been linearized with respect to upright position and then control signals have been applied in the direction of eigenvectors. Robustness of each method...
Stabilizing periodic orbits of chaotic systems using adaptive critic-based neurofuzzy controller
, Article Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference 2009, DETC2009, 30 August 2009 through 2 September 2009 ; Volume 4, Issue PART C , August–September , 2010 , Pages 1759-1767 ; 9780791849019 (ISBN) ; Vatankhah, R ; Salarieh, H ; Boroushaki, M ; Alasty, A ; Sharif University of Technology
2010
Abstract
In this paper design and evaluation of an adaptive critic- based neurofuzzy controller for the stabilizing periodic orbits of chaotic systems has been presented in detail. The main superiority of the proposed controller over previous analogous fuzzy logic controller design approaches, e.g., genetic fuzzy logic controller, is its online tuning characteristic and remarkable reduced amount of computations used for parameter adaptation, which makes it desirable for real time applications. Considering the simplicity of this controller and its independence from the system model, this control method has the advantage of online learning and control, and can be applied to a large variety of systems....