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optimal-control
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An optimal and decentralized transactive energy system for electrical grids with high penetration of renewable energy sources
, Article International Journal of Electrical Power and Energy Systems ; Volume 113 , 2019 , Pages 850-860 ; 01420615 (ISSN) ; Amirzadeh Goghari, S ; Nasiri Gheidari, Z ; Ranjbar, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this paper, a hierarchical frequency regulation system is presented for real-time operation of the electrical grids. It includes a decentralized transactive energy system for clearing transactions of producers/consumers in real-time. The proposed system is implemented in a distributed fashion with small data communication requirement. It is proved that the proposed transactive energy system converges to the optimal power flow (OPF). An iterative method for optimizing control parameters of the proposed hierarchical frequency regulation system is also given. The proposed method is developed for high penetration of renewable energy sources (RESs) as the sizes, locations, and uncertainties of...
Advanced modeling and control of 5 MW wind turbine using global optimization algorithms
, Article Wind Engineering ; Volume 43, Issue 5 , 2019 , Pages 488-505 ; 0309524X (ISSN) ; Majidi Pishkenari, M ; Sohrabi, S ; Feizarefi, M ; Sharif University of Technology
SAGE Publications Inc
2019
Abstract
This article presents a methodological approach for controller gain tuning of wind turbines using global optimization algorithms. For this purpose, the wind turbine structural and aerodynamic modeling are first described and a complete model for a 5 MW wind turbine is developed as a case study based on a systematic modeling approach. The turbine control requirements are then described and classified using its power curve to generate an appropriate control structure for satisfying all turbine control modes simultaneously. Next, the controller gain tuning procedure is formulated as an engineering optimization problem where the command tracking error and minimum response time are defined as...
A unified acceptance test framework for power plant gas turbine control systems
, Article ISA Transactions ; Volume 85 , 2019 , Pages 262-273 ; 00190578 (ISSN) ; Babazadeh, M ; Sharif University of Technology
ISA - Instrumentation, Systems, and Automation Society
2019
Abstract
Renovation and retrofit of gas turbine control systems yield significant economic savings, enhanced reliability, and improved performance. In recent years, the gas turbine industry is increasingly facing the need to well-established procedures for the acceptance tests of renovated control systems. This paper proposes a unified framework to evaluate the performance of renovated gas turbine control systems. Under a set of assumptions on the ambient and fuel conditions, a low-complexity modular model is presented and identified using optimization-oriented identification techniques. The accuracy of the proposed model is validated through experimental studies in full-load, min-load, and no-load...
Wind-tolerant optimal closed loop controller design for a domestic atmospheric research airship
, Article Mechanics Based Design of Structures and Machines ; 2020 ; Pourtakdoust, S. H ; Pazooki, F ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Airships are inherently sensitive to random atmospheric disturbances that could potentially make their data gathering and observation missions a formidable task. In this context robust closed loop feedback controllers are important. The present study is therefore focused on optimal feedback controller design of an indigenous domestically designed airship (DA) for added robustness against atmospheric disturbances. While the general airship six degrees of freedom (6DoF) governing equations of motion are mathematically nonlinear, one often needs to resort to local linearization methods to benefit from proven linear closed loop controller (CLC) design approaches. In this sense an optimal linear...
Artificial neural network integrated with thermodynamic equilibrium modeling of downdraft biomass gasification-power production plant
, Article Energy ; Volume 213 , 2020 ; Ebrahimi Saryazdi, S. M ; Unnthorsson, R ; Richter, C ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This study is a novel attempt in developing of an Artificial neural network (ANN) model integrated with a thermodynamic equilibrium approach for downdraft biomass gasification integrated power generation unit. The objective of the study is to predict the net output power from the systems derived from various kinds of biomass feedstocks under atmospheric pressure and various operating conditions. The input parameters used in the models are elemental analysis compositions (C, O, H, N and S), proximate analysis compositions (moisture, ash, volatile material and fixed carbon) and operating parameters (gasifier temperature and air to fuel ratio). The architecture of the model consisted of one...
Closed loop near time optimal magnetic attitude control using dynamic weighted neural network
, Article 2008 Mediterranean Conference on Control and Automation, MED'08, Ajaccio-Corsica, 25 June 2008 through 27 June 2008 ; 2008 , Pages 23-28 ; 9781424425051 (ISBN) ; Pourtakdoust, S. H ; Sharif University of Technology
2008
Abstract
The problem of time optimal magnetic attitude control is treated and an open loop solution is first obtained using a variational approach. In order to close the control loop, a neural network with time varying weights is proposed as a feedback optimal controller applicable to the time varying nonlinear system. The good robustness and low real-time computational burden of the proposed neuro-controller makes the controller more useful compared to the other control methods. © 2008 IEEE
Finding arbitrary shaped clusters and color image segmentation
, Article 1st International Congress on Image and Signal Processing, CISP 2008, Sanya, Hainan, 27 May 2008 through 30 May 2008 ; Volume 1 , 2008 , Pages 593-597 ; 9780769531199 (ISBN) ; Bagheri Shouraki, S ; Sharif University of Technology
2008
Abstract
One of the most famous approaches for the segmentation of color images is finding clusters in the color space. Shapes of these clusters are often complex and the time complexity of the existing algorithms for finding clusters of different shapes is usually high. In this paper, a novel clustering algorithm is proposed and used for the image segmentation purpose. This algorithm distinguishes clusters of different shapes using a two-stage clustering approach in a reasonable time. In the first stage, the mean-shift clustering algorithm is used and the data points are grouped into some sub-clusters. In the second stage, connections between sub-clusters are established according to a dissimilarity...
Estimation of practical Inter-Modulation Rejection values in a multi-loop feed-forward microwave power amplifier using Monte-Carlo method
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 632-637 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Hemmatyar, A ; Farzaneh, F ; Sharif University of Technology
2007
Abstract
Feed-forward is one of the best methods for linearizing microwave power amplifiers, but due to device tolerance in implementation of the system components, the practical Inter-Modulation Rejection (IMR) value may differ quite much from the theoretical IMR value. One of the methods to improve the practical performance of the system is using the multi-loop configuration. Here we have introduced the multi-loop feedforward systems and we have estimated the practical IMR values of the system using Monte-Carlo analysis. As the analysis shows, although the number of components in a multi-loop system is increased with respect to a simple feed-forward system, but the difference between the practical...
Optimal control of robot manipulators using fuzzy interaction prediction system
, Article 2006 IEEE International Conference on Robotics and Biomimetics, ROBIO 2006, Kunming, 17 December 2006 through 20 December 2006 ; 2006 , Pages 1071-1076 ; 1424405718 (ISBN); 9781424405718 (ISBN) ; Emamzadeh, M. M ; Sharif University of Technology
2006
Abstract
In this paper, a new fuzzy coordination method based on Interaction Prediction Principle (IPP) is presented for the optimal control of robot manipulators. For this purpose, the robot manipulator is considered as a two-level large-scale system where in the first level, the overall system is decomposed into several subsystems. Each subsystem can include one or more consecutive links and joints. In the second level, a fuzzy interaction prediction system is introduced for coordination of the overall system where a critic vector is also used for evaluation of its performance. The simulation results of using the proposed novel approach ,for optimal control of robot manipulators, show its...
Wind-tolerant optimal closed loop controller design for a domestic atmospheric research airship
, Article Mechanics Based Design of Structures and Machines ; Volume 50, Issue 6 , 2022 , Pages 2046-2066 ; 15397734 (ISSN) ; Pourtakdoust, S. H ; Pazooki, F ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Airships are inherently sensitive to random atmospheric disturbances that could potentially make their data gathering and observation missions a formidable task. In this context robust closed loop feedback controllers are important. The present study is therefore focused on optimal feedback controller design of an indigenous domestically designed airship (DA) for added robustness against atmospheric disturbances. While the general airship six degrees of freedom (6DoF) governing equations of motion are mathematically nonlinear, one often needs to resort to local linearization methods to benefit from proven linear closed loop controller (CLC) design approaches. In this sense an optimal linear...
Robust multivariable predictive based load frequency control considering generation rate constraint
, Article International Journal of Electrical Power and Energy Systems ; Volume 46, Issue 1 , March , 2013 , Pages 405-413 ; 01420615 (ISSN) ; Toulabi, M. R ; Ranjbar, A. M ; Sharif University of Technology
2013
Abstract
In this paper, a robust multivariable Model based Predictive Control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area power system. The proposed control scheme is designed to consider multivariable nature of LFC, system uncertainty and generation rate constraint, simultaneously. A constrained MPC is employed to calculate optimal control input including generation rate constraints. Economic allocation of generation is further ensured by modification of the predictive control objective function. To achieve robustness against system uncertainty and variation of parameters, a linear matrix inequality (LMI) based approach is employed. To validate the...
Toward design and fabrication of wind-driven vehicles: Procedure to optimize the threshold of driving forces
, Article Applied Mathematical Modelling ; Volume 37, Issue 1-2 , 2013 , Pages 50-61 ; 0307904X (ISSN) ; Rad, M ; Sharif University of Technology
2013
Abstract
Wind energy has been continuously considered as a green, available, and economical alternative source of energy. For centuries, the transformed wind energy to drag-force has been used for transportation in watercrafts. With improvement of aerodynamics, the airfoil was invented to create and use a higher magnitude aerodynamic force, lift-force, in order to elevate airplanes. Later, the lift-force was horizontally applied as the thrust force in land/water wind-crafts. Whereas in airplanes horizontal airfoils (wing) create a vertical lift-force, installed vertical airfoils (wing-sail) produce a horizontal lift-force in wind-crafts. Therefore, this force can be used as thrust (driving) force in...
Vibration control of beams on elastic foundation under a moving vehicle and random lateral excitations
, Article Journal of Sound and Vibration ; Volume 331, Issue 6 , March , 2012 , Pages 1217-1232 ; 0022460X (ISSN) ; Khaloo, A. R ; Sharif University of Technology
2012
Abstract
The formulation of three-dimensional dynamic behavior of a Beam On Elastic Foundation (BOEF) under moving loads and a moving mass is considered. The weight of the vehicle is modeled as a moving point load, however the effect of the lateral excitation is considered by modeling: (case 1) a lateral moving load with random intensity for wind excitation and (case 2) a moving mass just in lateral direction of the beam for earthquake excitation. A Dirac-delta function is used to describe the position of the moving load and the moving mass along the beam. The beam foundations are considered as elastic Winkler-type in two perpendicular transverse directions. This model is proposed to investigate the...
Semi active vibration control of a passenger car using magnetorheological shock absorber
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, Istanbul, 12 July 2010 through 14 July 2010 ; Volume 3 , 2010 , Pages 21-27 ; 9780791849170 (ISBN) ; Zabihollah, A ; Sharif University of Technology
2010
Abstract
A novel semi-active control system for suspension systems of passenger car using Magnetorheological (MR) damper is introduced. The suspension system is considered as a mass-spring model with an eight-degrees-of-freedom, a passive damper and an active damper. The semi-active vibration control is designed to reduce the amplitude of automotive vibration caused by the alteration of road profile. The control mechanism is designed based on the optimal control algorithm, Linear Quadratic Regulator (LQR). In this system, the damping coefficient of the shock absorber changes actively trough inducing magnetic field. It is observed that utilizing the present control algorithm may significantly reduce...
Elitist continuous ant colony optimization algorithm for optimal management of coastal aquifers
, Article Water Resources Management ; Volume 25, Issue 1 , 2010 , Pages 165-190 ; 09204741 (ISSN) ; Ketabchi, H ; Sharif University of Technology
2010
Abstract
This paper presents an evolutionary based approach to achieve optimal management of a coastal aquifer to control saltwater intrusion. An improved Elitist Continuous Ant Colony Optimization (ECACO) algorithm is employed for optimal control variables setting of coastal aquifer management problem. The objectives of the optimal management are; maximizing the total water-pumping rate, while controlling the drawdown limits and protecting the wells from saltwater intrusion. Since present work is one of the first efforts towards the application of an ECACO algorithm, sharp interface solution for steady state problem is first exploited. The performance of the developed optimization model is evaluated...
Design of a fractional order PID controller for an AVR using particle swarm optimization
, Article Control Engineering Practice ; Volume 17, Issue 12 , 2009 , Pages 1380-1387 ; 09670661 (ISSN) ; Karimi Ghartemani, M ; Sadati, N ; Parniani, M ; Sharif University of Technology
Abstract
Application of fractional order PID (FOPID) controller to an automatic voltage regulator (AVR) is presented and studied in this paper. An FOPID is a PID whose derivative and integral orders are fractional numbers rather than integers. Design stage of such a controller consists of determining five parameters. This paper employs particle swarm optimization (PSO) algorithm to carry out the aforementioned design procedure. PSO is an advanced search procedure that has proved to have very high efficiency. A novel cost function is defined to facilitate the control strategy over both the time-domain and the frequency-domain specifications. Comparisons are made with a PID controller and it is shown...
A neuro-optimal approach for thrust-insensitive trajectory planning
, Article Aircraft Engineering and Aerospace Technology ; Volume 81, Issue 3 , 2009 , Pages 212-220 ; 00022667 (ISSN) ; Pazooki, F ; Noushabadi, F ; Sharif University of Technology
2009
Abstract
Purpose - The purpose of this paper is to devise a new approach to synthesize closed-loop feedback guidance law for online thrust- insensitive optimal trajectory generation utilizing neural networks. Design/methodology/approach - The proposed methodology utilizes an open- loop variational formulation that initially determines optimal launch/ ascent trajectories for various scenarios of known uncertainties in the thrust profile of typical solid propellant engines. These open-loop optimized trajectories will then provide the knowledge base needed for the subsequent training of a neural network. The trained network could eventually produce thrust-insensitive closed-loop optimal guidance laws...
Optimal control of an assisted passive snake-like robot using feedback linearization
, Article 31st Mechanisms and Robotics Conference, presented at - 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2007, Las Vegas, NV, 4 September 2007 through 7 September 2007 ; Volume 8 PART B , 2008 , Pages 867-876 ; 0791848027 (ISBN); 9780791848029 (ISBN); 0791848094 (ISBN); 9780791848098 (ISBN) ; Pendar, H ; Heidari, Z ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
2008
Abstract
In this paper we follow two approaches in optimal nonlinear control of a snake-like robot. After deriving the dynamic equations of motion using Gibbs-Appell method, reducing these equations, and some assumptions, feedback-linearization method was used to linearize the nonlinear system. The obtained controller is used in simulations to control robot to track a desired line, with minimum required torques. Two goals are desired. First the robot's head is expected to track a distinct line with a given speed. And next, tracking the serpenoid curve is desired. The simulation results prove the controller efficiency. The robustness of the designed controller is shown by comparing the torques with...
Active queue management of TCP/IP networks using rule-based predictive control
, Article 2007 IEEE International Symposium on Industrial Electronics, ISIE 2007, Caixanova - Vigo, 4 June 2007 through 7 June 2007 ; 2007 , Pages 77-82 ; 1424407559 (ISBN); 9781424407552 (ISBN) ; Bigdeli, N ; Haeri, M ; Sharif University of Technology
2007
Abstract
Model predictive controllers, due to their capability to control the time variant and delayed systems, are considered for congestion control in computer networks. To extend the application of these controllers as an active queue management (AQM) system in dynamic TCP/IP networks, a new rule-based predictive controller is proposed. This controller uses the small signal linearized fluid-flow model of the TCP/IP networks and simulates the future behavior of control system by applying few candidate control sequences. Using the extremes of the resulted predicted output sequences, optimal control signal is determined based on some appropriate rules. This approach benefits from the mentioned...
Discrimination between Alzheimer's disease and control group in MR-images based on texture analysis using artificial neural network
, Article ICBPE 2006 - 2006 International Conference on Biomedical and Pharmaceutical Engineering, Singapore, 11 December 2006 through 14 December 2006 ; 2006 , Pages 79-83 ; 8190426249 (ISBN); 9788190426244 (ISBN) ; Ardekani, R. D ; Fatemizadeh, E ; Sharif University of Technology
2006
Abstract
In this study, we have proposed a novel method investigates MR-Images for normal and abnormal brains which effected by Alzheimer's Disease (AD) to extract 336 number of different features based on texture analysis. Before applying this algorithm, we have to use a registration method because of variety in size of normal and abnormal images. Consequently, the output of Texture Analysis System (TAS) is a vector containing 336 elements that are features extracted from texture. This vector is considered as the input of the Artificial Neural Network (ANN) which is feed-forward one. The features extracted from the Gray-level Co-occurrence Matrix (GLCM) have been interpreted and compared with normal...