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    Smooth switching in a scheduled robust model predictive controller

    , Article Journal of Process Control ; Volume 31 , 2015 , Pages 55-63 ; 09591524 (ISSN) Khani, F ; Haeri, M ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Abstract This paper proposes a bumpless transfer method to overcome the problem of switching jumps in a scheduled robust model predictive control approach. A scheduled robust model predictive controller implements a set of local robust model predictive controllers based on an on-line switching strategy. This method could enlarge the domain of attraction efficiently but the transient response might be hampered by spikes appearing at the moment of switching between adjacent local controllers. The proposed algorithm could enhance the transient response by implementing some intermediate controllers augmented to the main control scheme to solve the problem without needing more computation. The... 

    Constrained tracking control for nonlinear systems

    , Article ISA Transactions ; Volume 70 , 2017 , Pages 64-72 ; 00190578 (ISSN) Khani, F ; Haeri, M ; Sharif University of Technology
    Abstract
    This paper proposes a tracking control strategy for nonlinear systems without needing a prior knowledge of the reference trajectory. The proposed method consists of a set of local controllers with appropriate overlaps in their stability regions and an on-line switching strategy which implements these controllers and uses some augmented intermediate controllers to ensure steering the system states to the desired set points without needing to redesign the controller for each value of set point changes. The proposed approach provides smooth transient responses despite switching among the local controllers. It should be mentioned that the stability regions of the proposed controllers could be... 

    Robust modeling, sliding-mode controller, and simulation of an underactuated rov under parametric uncertainties and disturbances

    , Article Journal of Marine Science and Application ; 2018 ; 16719433 (ISSN) Eslami, M ; Chin, C. S ; Nobakhti, A ; Sharif University of Technology
    Harbin Engineering University  2018
    Abstract
    A dynamic model of a remotely operated vehicle (ROV) is developed. The hydrodynamic damping coefficients are estimated using a semi-predictive approach and computational fluid dynamic software ANSYS-CFX™ and WAMIT™. A sliding-mode controller (SMC) is then designed for the ROV model. The controller is subsequently robustified against modeling uncertainties, disturbances, and measurement errors. It is shown that when the system is subjected to bounded uncertainties, the SMC will preserve stability and tracking response. The paper ends with simulation results for a variety of conditions such as disturbances and parametric uncertainties. © 2018, Harbin Engineering University and Springer-Verlag... 

    Robust modeling, sliding-mode controller, and simulation of an underactuated rov under parametric uncertainties and disturbances

    , Article Journal of Marine Science and Application ; Volume 18, Issue 2 , 2019 , Pages 213-227 ; 16719433 (ISSN) Eslami, M ; Chin, C. S ; Nobakhti, A ; Sharif University of Technology
    Harbin Engineering University  2019
    Abstract
    A dynamic model of a remotely operated vehicle (ROV) is developed. The hydrodynamic damping coefficients are estimated using a semi-predictive approach and computational fluid dynamic software ANSYS-CFX™ and WAMIT™. A sliding-mode controller (SMC) is then designed for the ROV model. The controller is subsequently robustified against modeling uncertainties, disturbances, and measurement errors. It is shown that when the system is subjected to bounded uncertainties, the SMC will preserve stability and tracking response. The paper ends with simulation results for a variety of conditions such as disturbances and parametric uncertainties. © 2018, Harbin Engineering University and Springer-Verlag... 

    Integrated guidance and control of elastic flight vehicle based on robust MPC

    , Article International Journal of Robust and Nonlinear Control ; 2014 Shamaghdari, S ; Nikravesh, S. K. Y ; Haeri, M ; Sharif University of Technology
    Abstract
    Integrated guidance and control of an elastic flight vehicle based on constrained robust model predictive control is proposed. The design is based on a partial state feedback control law that minimizes a cost function within the framework of linear matrix inequalities. It is shown that the solution of the defined optimization problem stabilizes the nonlinear plant. Nonlinear kinematics and dynamics are taken into account, and internal stability of the closed-loop nonlinear system is guaranteed. The performance and effectiveness of the proposed integrated guidance and control against non-maneuvering and weaving targets are evaluated using computer simulations  

    Generating unrestricted adversarial examples via three parameteres

    , Article Multimedia Tools and Applications ; Volume 81, Issue 15 , 2022 , Pages 21919-21938 ; 13807501 (ISSN) Naderi, H ; Goli, L ; Kasaei, S ; Sharif University of Technology
    Springer  2022
    Abstract
    Deep neural networks have been shown to be vulnerable to adversarial examples deliberately constructed to misclassify victim models. As most adversarial examples have restricted their perturbations to the Lp-norm, existing defense methods have focused on these types of perturbations and less attention has been paid to unrestricted adversarial examples; which can create more realistic attacks, able to deceive models without affecting human predictions. To address this problem, the proposed adversarial attack method generates an unrestricted adversarial example with a limited number of parameters. The attack selects three points on the input image and based on their locations transforms the... 

    Robust Optimization Model for The Distribution Process of Petroleum Products

    , M.Sc. Thesis Sharif University of Technology Miri, Ali (Author) ; Eshghi, Kourosh (Supervisor)
    Abstract
    The human need for reliable and accessible energy sources for household, industrial, transportation, etc. caused the discovery of the first oil well to move towards exploitation and use of this large, cheap and available energy source, accelerated. With the start of this movement, oil and its products in the last two centuries have quickly established themselves as a major part of the energy basket of most countries in the world. The entry of crude oil and its products into the energy industry has faced new issues and challenges for decision makers in this field. One of the most important challenges has been the planning and management of the process of distribution and transfer of petroleum... 

    Computational load reduction in model predictive control of nonlinear systems via decomposition

    , Article 5th International Conference on Control, Instrumentation, and Automation, ICCIA 2017, 21 November 2017 through 23 November 2017 ; Volume 2018-January , 2018 , Pages 216-221 ; 9781538621349 (ISBN) Adelipour, S ; Rastgar, M ; Haeri, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    The aim of this study is to reduce the computational load in model predictive control of multi-input nonlinear systems. First, the nonlinear system which has a high number of states and inputs is decomposed into several subsystems by solving a linear integer programming problem offline. Then, the model of each subsystem is revised by considering the effect of coupling and interactions of other subsystems. Next, the robust model predictive technique based on linear matrix inequalities is employed to compute control signal for each subsystem. An industrial chemical reaction example is used to illustrate the effectiveness of the proposed method. © 2017 IEEE  

    Design of a robust model predictive controller with reduced computational complexity

    , Article ISA Transactions ; Volume 53, Issue 6 , 1 November , 2014 , Pages 1754-1759 ; ISSN: 00190578 Razi, M ; Haeri, M ; Sharif University of Technology
    Abstract
    The practicality of robust model predictive control of systems with model uncertainties depends on the time consumed for solving a defined optimization problem. This paper presents a method for the computational complexity reduction in a robust model predictive control. First a scaled state vector is defined such that the objective function contours in the defined optimization problem become vertical or horizontal ellipses or circles, and then the control input is determined at each sampling time as a state feedback that minimizes the infinite horizon objective function by solving some linear matrix inequalities. The simulation results show that the number of iterations to solve the problem... 

    Integrated guidance and control of elastic flight vehicle based on robust MPC

    , Article International Journal of Robust and Nonlinear Control ; Volume 25, Issue 15 , 2015 , Pages 2608-2630 ; 10498923 (ISSN) Shamaghdari, S ; Nikravesh, S. K. Y ; Haeri, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2015
    Abstract
    Integrated guidance and control of an elastic flight vehicle based on constrained robust model predictive control is proposed. The design is based on a partial state feedback control law that minimizes a cost function within the framework of linear matrix inequalities. It is shown that the solution of the defined optimization problem stabilizes the nonlinear plant. Nonlinear kinematics and dynamics are taken into account, and internal stability of the closed-loop nonlinear system is guaranteed. The performance and effectiveness of the proposed integrated guidance and control against non-maneuvering and weaving targets are evaluated using computer simulations  

    A new analytical model of a radial turbine and validation by experiments

    , Article IEEE Aerospace Conference Proceedings, 6 March 2010 through 13 March 2010 ; March , 2010 ; 1095323X (ISSN) ; 9781424438884 (ISBN) Pourfarzaneh, H ; Hajilouy Benisi, A ; Farshchi, M ; Sharif University of Technology
    2010
    Abstract
    In the conceptual design phase of a turbocharger, where emphasis is mainly on parametric studies, before manufacturing and tests, a generalized and robust model that applies over a wide range properly, is unavoidable. 12The critical inputs such as turbine maps are not available during the conceptual design phase. Hence, generalized turbine models use alternate methods that work without any supplementary tests and can operate over wide ranges. One of the common and applicable modeling methods in design process is 'Dimensionless Modeling' using the constant coefficient scaling (CCS). This method can almost predict the turbine characteristics at the design point. However, at off-design... 

    A new analytical model of a centrifugal compressor and validation by experiments

    , Article Journal of Mechanics ; Volume 26, Issue 1 , 2010 , Pages 37-45 ; 17277191 (ISSN) Pourfarzaneh, H ; Hajilouy Benisi, A ; Farshchi, M ; Sharif University of Technology
    2010
    Abstract
    In the conceptual design phase of a turbocharger, where emphasis is mainly on parametric studies, before manufacturing and tests, a generalized and robust model that implies over a wide range properly, is unavoidable. The critical inputs such as compressor maps are not available during the conceptual design phase. Hence, generalized compressor models use alternate methods that work without any supplementary tests and can operate on wide range. One of the common and applicable modeling methods in design process is the 'Dimensionless Modeling' using the constant coefficient scaling (CCS). This method almost can predict the compressor characteristics at design point. However, at off design... 

    Design of an RMPC with a time-varying terminal constraint set for tracking problem

    , Article International Journal of Robust and Nonlinear Control ; Volume 26, Issue 12 , 2016 , Pages 2623-2642 ; 10498923 (ISSN) Razi, M ; Haeri, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    This paper presents a robust model predictive control algorithm with a time-varying terminal constraint set for systems with model uncertainty and input constraints. In this algorithm, the nonlinear system is approximated by a linear model where the approximation error is considered as an unstructured uncertainty that can be represented by a Lipschitz nonlinear function. A continuum of terminal constraint sets is constructed off-line, and robust stability is achieved on-line by using a variable control horizon. This approach significantly reduces the computational complexity. The proposed robust model predictive controller with a terminal constraint set is used in tracking set-points for... 

    Efficient algorithms for online tracking of set points in robust model predictive control

    , Article International Journal of Systems Science ; Volume 48, Issue 8 , 2017 , Pages 1635-1645 ; 00207721 (ISSN) Razi, M ; Haeri, M ; Sharif University of Technology
    Abstract
    This paper presents some computationally efficient algorithms for online tracking of set points in robust model predictive control context subject to state and input constraints. The nonlinear systems are represented by a linear model along with an additive nonlinear term which is locally Lipschitz. As an unstructured uncertainty, this term is replaced in the robust stability constraint by its Lipschitz coefficient. A scheduled control technique is employed to transfer the system to desired set points, given online, by designing local robust model predictive controllers. This scheme includes estimating the regions of feasibility and stability of the related equilibriums and online switching... 

    Decentralized robust model predictive control for multi-input linear systems

    , Article UKACC 12th International Conference on Control, CONTROL 2018, 5 September 2018 through 7 September 2018 ; 2018 , Pages 13-18 ; 9781538628645 (ISBN) Adelipour, S ; Haeri, M ; Pannocchia, G ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    In this paper, a decentralized model predictive control approach is proposed for discrete linear systems with a high number of inputs and states. The system is decomposed into several interacting subsystems. The interaction among subsystems is modeled as external disturbances. Then, using the concept of robust positively invariant ellipsoids, a robust model predictive control law is obtained for each subsystem solving several linear matrix inequalities. Maintaining the recursive feasibility while considering the attenuation of mutual coupling at each time step and the stability of the overall system are investigated. Moreover, an illustrative simulation example is provided to demonstrate the... 

    Model predictive control of nonlinear discrete time systems with guaranteed stability

    , Article Asian Journal of Control ; 2018 ; 15618625 (ISSN) Shamaghdari, S ; Haeri, M ; Sharif University of Technology
    Wiley-Blackwell  2018
    Abstract
    This paper presents the design of a new robust model predictive control algorithm for nonlinear systems represented by a linear model with unstructured uncertainty. The linear model is obtained by linearizing the nonlinear system at an operating point and the difference between the nonlinear and linear model is considered as a Lipschitz nonlinear function. The controller is designed for the linear model, which fulfills the stabilization condition for the nonlinear term. Unlike previous studies that have not considered a valid Lipschitz matrix of nonlinear term in the design process, we propose an algorithm in this paper in which it is considered. Therefore, the closed loop stability of the... 

    A novel robust model reference adaptive impedance control scheme for an active transtibial prosthesis

    , Article Robotica ; Volume 37, Issue 9 , 2019 , Pages 1562-1581 ; 02635747 (ISSN) Heidarzadeh, S ; Sharifi, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    Cambridge University Press  2019
    Abstract
    In this paper, a novel robust model reference adaptive impedance control (RMRAIC) scheme is presented for an active transtibial ankle prosthesis. The controller makes the closed loop dynamics of the prosthesis similar to a reference impedance model and provides asymptotic tracking of the response trajectory of this impedance model. The interactions between human and prosthesis are taken into account by designing a second-order reference impedance model. The proposed controller is robust against parametric uncertainties in the nonlinear dynamic model of the prosthesis. Also, the controller has robustness against bounded uncertainties due to unavailable ground reaction forces and unmeasurable... 

    Model predictive control of nonlinear discrete time systems with guaranteed stability

    , Article Asian Journal of Control ; Volume 22, Issue 2 , 2020 , Pages 657-666 Shamaghdari, S ; Haeri, M ; Sharif University of Technology
    Wiley-Blackwell  2020
    Abstract
    This paper presents the design of a new robust model predictive control algorithm for nonlinear systems represented by a linear model with unstructured uncertainty. The linear model is obtained by linearizing the nonlinear system at an operating point and the difference between the nonlinear and linear model is considered as a Lipschitz nonlinear function. The controller is designed for the linear model, which fulfills the stabilization condition for the nonlinear term. Unlike previous studies that have not considered a valid Lipschitz matrix of nonlinear term in the design process, we propose an algorithm in this paper in which it is considered. Therefore, the closed loop stability of the... 

    A multi-objective stochastic programming approach for supply chain design considering risk

    , Article International Journal of Production Economics ; Volume 116, Issue 1 , 2008 , Pages 129-138 ; 09255273 (ISSN) Azaron, A ; Brown, K. N ; Tarim, S. A ; Modarres, M ; Sharif University of Technology
    2008
    Abstract
    In this paper, we develop a multi-objective stochastic programming approach for supply chain design under uncertainty. Demands, supplies, processing, transportation, shortage and capacity expansion costs are all considered as the uncertain parameters. To develop a robust model, two additional objective functions are added into the traditional comprehensive supply chain design problem. So, our multi-objective model includes (i) the minimization of the sum of current investment costs and the expected future processing, transportation, shortage and capacity expansion costs, (ii) the minimization of the variance of the total cost and (iii) the minimization of the financial risk or the... 

    Applying flow zone index approach and artificial neural networks modeling technique for characterizing a heterogeneous carbonate reservoir using dynamic data: Case Study of an Iranian reservoir

    , Article Society of Petroleum Engineers - Trinidad and Tobago Energy Resources Conference 2010, SPE TT 2010, 27 June 2010 through 30 June 2010 ; Volume 2 , June , 2010 , Pages 677-690 ; 9781617388859 (ISBN) Shahvar, M. B ; Kharrat, R ; Matin, M ; Sharif University of Technology
    2010
    Abstract
    Although static characterization of reservoirs is an inevitable part of any reservoir studies, the most robust models of the reservoirs can be obtained through integrating static and dynamic data. The following study which is done in a heterogeneous carbonate reservoir utilizes the capillary pressure and relative permeability data to verify the task of static rock typing and investigate the role of hydraulic units in capillary pressure and relative permeability modeling. For this purpose, at first, various rock typing techniques are applied to the field data to seek the best method which has the most consistency with capillary pressure curves. Using Desouky method which is based on hydraulic...