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Transition Flight Control of a Tilt Tri-Rotor UAV Using Robust Model Predictive Control
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor) ; Emami, Ali (Co-Supervisor)
Abstract
The purpose of this thesis is to control altitude and attitude of a Tilt Tri-Rotor UAV in rotorcraft mode and control of altitude, attitude and forward velocity in transition mode (from rotorcraft mode to cruise) by using model predictive control. First, the detailed mathematical model is obtained by the Newton-Euler equations of motion, in both rotorcraft and transition modes. In the next step, a MIMO model predictive controller has been designed, considering input constraints. Then, since, robustness of the model-based control approach is an important challenge, the performance of the controller is presented in the presence of model uncertainties and wind disturbances. The results indicate...
Model Predictive Control Applications in Turbocompressor Control System
, Ph.D. Dissertation Sharif University of Technology ; Alasty, Aria (Supervisor) ; Vossoughi, Gholamreza (Supervisor)
Abstract
The purpose of this study is to develop model predictive control approach to control a turbocompressor. The turbocompressor which is consisted of a gas turbine and a centrifugal compressor is manufactured for providing the necessary pressure for gas transport via the gas transmission network. The turbocompressor control system regulates the compressor outlet pressure by controlling the rotational speed of the gas turbine, while preventing the surge phenomenon in the compressor. Surge is a serious instability in the compressor that is associated with periodic fluctuations in system variables and can cause heavy damage to expensive machine parts.In this research, model predictive control has...
Blood Glucose Control for Type 1 Diabetes Patients with Explicit Model Predictive Control (MPC)
, M.Sc. Thesis Sharif University of Technology ; Alasty, Aria (Supervisor) ; Vahidi, Omid (Co-Supervisor)
Abstract
Blood glucose regulation in type 1 diabetes patients requires the delivery of the proper amount of insulin from an external source. The literature of Blood Glucose Control signifies the superiority of model-based controllers over the other ones. Regarding its lack of need to complicated on-line calculations and the simplicity of its implementation on a micro-chip, the explicit Model Predictive Controller is preferred over the implicit MPC. Currently proposed explicit MPC controllers have employed relatively simple models representing human glucose-insulin dynamics. In this thesis, an explicit MPC controller is designed using mp-QP based on Sorensen’s 19-state comprehensive model which has...
Design, Modeling and Control of Multi-Port Converters
, M.Sc. Thesis Sharif University of Technology ; Oraee Mirzamani, Hashem (Supervisor)
Abstract
Because of environmental problems of fossil fuel energies and the rise in petroleum products, the tendencies to the renewable sources like wind power and solar power have been increased. In some particular applications like electric vehicles, satellites power system and all stand-alone unites that are using solar and wind powers are the only solutions. On the other hand, because of intermittent behavior of renewable sources, use of back-up supplies e.g. batteries are necessary to make a balance in power consumptions and productions. To interface between different ports some independent two port converters are used in traditional techniques. Multiport converters, used in...
Control effectiveness investigation of a ducted-fan aerial vehicle using model predictive controller
, Article International Conference on Advanced Mechatronic Systems, ICAMechS ; 2014 , pp. 532-537 ; Emami, S. A ; Sharif University of Technology
Abstract
Special attention is given to vertical takeoff and landing air vehicles due to their unique capabilities and versatile missions. The main problem here is control effectiveness at low flight speeds and transition maneuvers because of the inherent instability. RMIT is a small sized tail-sitter ducted fan air vehicle with a particular configuration layout, multiple control surfaces, low weight, and high-speed flight capability. In the current study, a comprehensive nonlinear model is firstly developed for RMIT, followed by a validation process. This model consists of all parts including aerodynamic forces and moments, control surfaces term together with the gravity and driving fan forces....
Hybrid modeling and control of a DC-DC boost converter via Extended Mixed Logical Dynamical systems (EMLDs)
, Article PEDSTC 2014 - 5th Annual International Power Electronics, Drive Systems and Technologies Conference ; 2014 , pp. 373-378 ; Mokhtari, H ; Sharif University of Technology
Abstract
The objective of this paper is to expand the concept of hybrid modeling and control in power electronics area. A new precise and non-averaged model of a DC-DC boost converter is developed on the basis of Mixed Logical Dynamical (MLD) systems, and the approach is extended by a new version of such systems which is called as Extended Mixed Logical Dynamical (EMLD) systems in this paper. A Model Predictive Controller (MPC) based on the Mixed Integer Quadratic Programming (MIQP) is designed for the MLD and EMLD models of the DC-DC boost converter considering all possible dynamics in Continuous and Discontinuous Conduction Modes of operations (CCM-DCM). The simulation results show the satisfactory...
Model predictive orbit control of a Low Earth Orbit satellite using Gauss's variational equations
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Vol. 228, issue. 13 , Oct , 2014 , p. 2385-2398 ; Assadian, N ; Sharif University of Technology
Abstract
In this paper, an autonomous orbit control of a satellite in Low Earth Orbit is investigated using model predictive control. The absolute orbit control problem is transformed to a relative orbit control problem in which the desired states of the reference orbit are the orbital elements of a virtual satellite which is not affected by undesirable perturbations. The relative motion is modeled by Gauss's variational equations including J2 and drag perturbations which are the dominant perturbations in Low Earth Orbit. The advantage of using Gauss's variational equations over the Cartesian formulations is that not only the linearization errors are much smaller, but also each orbital element can be...
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...
A new method to control heat and mass transfer to work piece in a GMAW process
, Article Journal of Process Control ; Volume 22, Issue 6 , 2012 , Pages 1087-1102 ; 09591524 (ISSN) ; Haeri, M ; Sharif University of Technology
2012
Abstract
It is proposed to employ melting rate, heat input, and detaching droplet diameter as controlled variables to control heat and mass transfer to work piece in a gas metal arc welding process. A two-layer architecture with cascade configuration of PI and MPC controllers is implemented to incorporate existing constraints on the process variables, improve transient behavior of the closed-loop responses and reduce interaction level. Computer simulation results are presented to indicate usefulness of the proposed controlled variables selection and applying two-layer control architecture to control heat and mass transfer to work piece
Robust model predictive control of nonlinear processes represented by Wiener or Hammerstein models
, Article Chemical Engineering Science ; Volume 129 , 2015 , Pages 223-231 ; 00092509 (ISSN) ; Haeri, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Representing nonlinear systems by linear models along with structured or unstructured uncertainties and applying robust control strategies could reduce the computational complexity in comparison with implementing the nonlinear model predictive controllers. In this paper design of robust model predictive controllers which are based on special classes of nonlinear systems representations called Wiener and Hammerstein are presented. The proposed algorithms approximate the nonlinear systems by uncertain linear models and reduce online the computational demands in the control implementation. The advantages of the proposed approaches are illustrated by two examples
Robustness investigation of a ducted-fan aerial vehicle control, using linear, adaptive, and model predictive controllers
, Article International Journal of Advanced Mechatronic Systems ; Volume 6, Issue 2-3 , 2015 , Pages 108-117 ; 17568412 (ISSN) ; Banazadeh, A ; Sharif University of Technology
Inderscience Publishers
2015
Abstract
A comparison of three common controllers for stabilising a vertical take-off and landing air vehicle is presented. RMIT is a small sized tail-sitter ducted fan air vehicle with a particular configuration layout, multiple control surfaces, low weight, and high-speed flight capability. The main problem here is control effectiveness at low flight speeds and transition manoeuvres because of the inherent instability. In the current study, a comprehensive nonlinear model is firstly developed for RMIT, followed by a validation process. Subsequently, linear, adaptive and model predictive controllers are designed in vertical flight. Based on the simulation results, it is shown that the linear...
Model reference control of PMSM drive systems based on model predictive control
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; 2015 , Pages 395-399 ; 9781479976539 (ISBN) ; Fazli, M ; Tahami, F ; Sharif University of Technology
Abstract
Servo drive systems require a fast dynamic response for position control applications. Conventional cascade control structure has sluggish response due to bandwidth limitations on speed and current control loop. To achieve a fast output response, model reference adaptive control methods can be used to remove the dynamics of inner control loops. In this paper, feed-forward signals are generated using model predictive control which is combined with the conventional cascade structure. Using this approach, a fast transient response and satisfactory tracking ability can be achieved. The proposed control configuration is verified by the simulation results
Enhancing power system resilience through hierarchical outage management in multi-microgrids
, Article IEEE Transactions on Smart Grid ; Volume 7, Issue 6 , 2016 , Pages 2869-2879 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
This paper proposes a hierarchical outage management scheme to enhance the resilience of a smart distribution system comprised of multi-microgrids against unexpected disaster events. In this regard, after identifying the main features and requirements for a resilient outage management scheme, an appropriate framework is devised and the roles and tasks of different management entities in a multi-microgrids system are introduced. Based on this framework, the microgrids schedule their available resources in the first stage using a novel model predictive control-based algorithm. In the second stage, distribution system operator coordinates the possible power transfers among the microgrids and...
A hierarchical scheme for outage management in multi-microgrids
, Article International Transactions on Electrical Energy Systems ; Volume 26, Issue 9 , 2016 , Pages 2023-2037 ; 20507038 (ISSN) ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
This paper investigates the operation of a smart distribution system comprised of multiple microgrids during emergency conditions. It proposes a two-stage hierarchical scheme for outage management in such a system to enhance the security of supply during contingencies. This goal is achieved through sharing the available generation and storage capacities among different microgrids. In doing so, a well-organized framework is devised in order to introduce the roles and tasks of each player in operation stage of a multi-microgrids system. Based on this framework, the general optimization model that needs to be evaluated at each stage of the proposed outage management scheme is formulated. In...
Role of outage management strategy in reliability performance of multi-microgrid distribution systems
, Article IEEE Transactions on Power Systems ; 2017 ; 08858950 (ISSN) ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Abstract
This paper develops a general framework for reliability assessment of multi-microgrid (MMG) distribution systems. It also investigates reliability impacts of coordinated outage man-agement strategies in a MMG distribution network. According to the proposed reliability evaluation framework, which is based on sequential Monte Carlo simulation method, distribution system is divided into smaller sections/microgrids based on protection sys-tem configuration and operating measures are efficiently simulat-ed considering different operation modes. In order to demonstrate the role of outage management strategy in reliability performance of MMG distribution systems, at first, the required features of...
A modified indirect model predictive control for modular multilevel converters
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 1366-1371 ; 9781509059638 (ISBN) ; Ravanji, M. H ; Parniani, M ; Sharif University of Technology
Abstract
Modular multilevel converter (MMC) is among the promising topologies used in high-voltage/power purposes, especially for high-voltage direct-current (HVDC) transmission systems. In this paper, a modified model predictive control (MPC) strategy for an MMC-HVDC system is presented. In the proposed MPC strategy, output current, circulating current and capacitors voltage are controlled separately. In order to reduce the computational burden of the controller, the output current is controlled directly without any optimization. For suppression of the circulating current, capacitors voltage variations are employed to settle the converter arms voltages to their reference values. In addition, the...
An enhanced hybrid modular multilevel converter for improved performance
, Article IEEE Transactions on Power Electronics ; 2018 ; 08858993 (ISSN) ; Ravanji, M. H ; Parniani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
This paper proposes an enhanced hybrid modular multilevel converter (MMC), which utilizes a combination of halfbridge submodules (HBSM) and at least one full-bridge submodule (FBSM). In the proposed structure, FBSMs work with half of the HBSMs nominal voltage in each arm. Due to the presence of FBSMs, HBSMs switching frequency drops significantly, which reduces the converter power loss compared to half-bridge based MMCs. Furthermore, because of redundant FBSMs, (2N+1)-modulation can be employed to generate the output voltage without increasing the circulating current, thus the converter performance is improved notably. Besides, with the redundant FBSMs the converter can continue its...
Role of outage management strategy in reliability performance of multi-microgrid distribution systems
, Article IEEE Transactions on Power Systems ; Volume 33, Issue 3 , May , 2018 , Pages 2359-2369 ; 08858950 (ISSN) ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
This paper develops a general framework for reliability assessment of multi-microgrid (MMG) distribution systems. It also investigates reliability impacts of coordinated outage management strategies in a MMG distribution network. According to the proposed reliability evaluation framework, which is based on sequential Monte Carlo simulation method, distribution system is divided into smaller sections/microgrids based on protection system configuration and operating measures are efficiently simulated considering different operation modes. In order to demonstrate the role of outage management strategy in reliability performance of MMG distribution systems, at first, the required features of an...
Predictive fault-tolerant control of an all-thruster satellite in 6-DOF motion via neural network model updating
, Article Advances in Space Research ; Volume 61, Issue 6 , March , 2018 , Pages 1588-1599 ; 02731177 (ISSN) ; Assadian, N ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The problem of controlling an all-thruster spacecraft in the coupled translational-rotational motion in presence of actuators fault and/or failure is investigated in this paper. the nonlinear model predictive control approach is used because of its ability to predict the future behavior of the system. The fault/failure of the thrusters changes the mapping between the commanded forces to the thrusters and actual force/torque generated by the thruster system. Thus, the basic six degree-of-freedom kinetic equations are separated from this mapping and a set of neural networks are trained off-line to learn the kinetic equations. Then, two neural networks are attached to these trained networks in...
Global hybrid modeling and control of a buck converter: a novel concept
, Article International Journal of Circuit Theory and Applications ; Volume 37, Issue 9 , 2009 , Pages 968-986 ; 00989886 (ISSN) ; Mokhtari, H ; Sharif University of Technology
2009
Abstract
Several attempts have been made to design suitable controllers for DC-DC converters. However, these designs suffer from model inaccuracy or their inability to desirably function in both continuous and discontinuous current modes. This paper presents a novel switching scheme based on hybrid modeling to control a buck converter using mixed logical dynamical (MLD) methodologies. The proposed method is capable of globally controlling the converter in both continuous and discontinuous current modes of operation by considering all constraints in the physical plant such as maximum inductor current and capacitor voltage limits. Different loads and input voltage disturbances are simulated in MATLAB...