Loading...
Search for: controller-performance
0.005 seconds
Total 38 records

    Design and implementation of extended predictive functional control for boiler-turbine unit of power plant

    , Article 24th Mediterranean Conference on Control and Automation, 21 June 2016 through 24 June 2016 ; 2016 , Pages 131-134 ; 9781467383455 (ISBN) Amirabadi Farahani, M ; Haeri, M ; MCA ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    Abstract
    In this paper, a new model predictive controller is introduced to control a power unit process with three inputs and three outputs. This method is proposed to reduce the complexity of the required computation. In fact, the presented controller ensures achieving an acceptable performance in the presence of noise and disturbances and reduces the volume of calculations to control a complex and nonlinear boilerturbine process. The simulation results indicate that the implementation of the proposed controller requires less computing time while the performance degradation is not more than five percent  

    Control performance enhancement of gas turbines in the minimum command selection strategy

    , Article ISA Transactions ; 2020 Eslami, M ; Banazadeh, A ; Sharif University of Technology
    ISA - Instrumentation, Systems, and Automation Society  2020
    Abstract
    Three novel methods, named α, ζ and ϵ, are suggested in this paper to recover the performance loss during switching in the gas turbine control systems. The Minimum Command Selection (MCS) in the gas turbine control systems prompts this performance loss. Any step towards more productivity with less aging factors have a great impact on the gas turbine's lifetime profit and vice versa. Although many hardware upgrades have been studied and applied to accomplish this, in many cases a low-risk manipulation in the software may yield equivalent achievement. State of the art gas turbine control systems are supposed to handle various forms of disturbances, several operation modes and relatively high... 

    Control performance enhancement of gas turbines in the minimum command selection strategy

    , Article ISA Transactions ; Volume 112 , 2021 , Pages 186-198 ; 00190578 (ISSN) Eslami, M ; Banazadeh, A ; Sharif University of Technology
    ISA - Instrumentation, Systems, and Automation Society  2021
    Abstract
    Three novel methods, named α, ζ and ϵ, are suggested in this paper to recover the performance loss during switching in the gas turbine control systems. The Minimum Command Selection (MCS) in the gas turbine control systems prompts this performance loss. Any step towards more productivity with less aging factors have a great impact on the gas turbine's lifetime profit and vice versa. Although many hardware upgrades have been studied and applied to accomplish this, in many cases a low-risk manipulation in the software may yield equivalent achievement. State of the art gas turbine control systems are supposed to handle various forms of disturbances, several operation modes and relatively high... 

    Nonlinear optimal control of two-level large-scale systems; Part I - Interaction prediction principle

    , Article ICIECA 2005: International Conference on Industrial Electronics and Control Applications 2005, Quito, 29 November 2005 through 2 December 2005 ; Volume 2005 , 2005 ; 0780394194 (ISBN); 9780780394193 (ISBN) Sadati, N ; Momeni, A. R ; Sharif University of Technology
    IEEE Computer Society  2005
    Abstract
    In this paper, which consists of two parts, a new two-level computational algorithm is used for nonlinear optimal control of large-scale systems. The two-level optimizer uses a new coordination strategy which is based on the gradient of interaction errors instead of the gradient of overall performance function. The advantages of the new method can be categorized into two parts: First, the new formulation is applicable to a large class of problems whilst the classical model coordination method is not. Second, it extremely reduces the number of iterations required for obtaining the overall optimal solution. Although the computational burden of the algorithm in the first level increases... 

    Controlling Atrial fibrillation using Cohen's model

    , Article 2011 18th Iranian Conference of Biomedical Engineering, ICBME 2011, 14 December 2011 through 16 December 2011 ; December , 2011 , Pages 60-63 ; 9781467310055 (ISBN) Aghajari, S ; Bahrami, F ; Sharif University of Technology
    2011
    Abstract
    Drug administration using infusion pumps can find application in treating patients with arrhythmias. These pumps can obviate the need to use drugs several times a day and automatically adapt the dosage to patient situation. Considering the importance of administration of right dosage, a perfect-controlled pump is needed to approach this goal. This paper focuses on controlling Atrial fibrillation (AF) arrhythmia. The abnormal heart rhythm that affects RR interval sequence and there have been some attempts to model these effects. One of these models is proposed by Cohen and colleges. Searching through the variables of this model, selecting the potential control variable (the one that its... 

    Stabilizing periodic orbits of the fractional order chaotic van der pol system

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 8, Issue PARTS A AND B , 2010 , pp. 175-183 ; ISBN: 9780791844458 Rahimi, M. A ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    Abstract
    In tins paper, stabilizing the unstable periodic orbits (UPO) in a chaotic fractional order system called Van der Pol is studied. Firstly, a technique for finding unstable periodic orbit in chaotic fractional order systems is stated. Then by applying tins technique to the van der Pol system, unstable periodic orbit of system is found. After that, a method is presented for stabilization of the discovered UPO based on theories stability of the linear integer order and fractional order systems. Finally, a linear feedback controller was applied to the system and simulation is done for demonstration of controller performance  

    Introducing an adaptive robust controller for artificial heart

    , Article Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, 24 June 2012 through 27 June 2012 ; June , 2012 , Pages 413-418 ; 21551774 (ISSN) ; 9781457711992 (ISBN) Ravanshadi, S ; Jahed, M ; Sharif University of Technology
    2012
    Abstract
    Prolonged and uncontrolled high shear stresses and turbulence can cause hemolysis, while alternating and low-level stresses may contribute to platelet activation and thrombus formation. Such deficiencies are reported for Total Artificial Heart (TAH) systems which are generally not fully capable of dynamic adaptation to sudden pressure and volume changes. This study introduces an adaptive robust controller for a linear motor based TAH (LMTAH) which overcomes such shortcomings. Proposed controller performance is compared with simulated natural heart in normal and stressed physiological conditions. Application of adaptive robust control results in flows with less stress variation and... 

    Modeling and control of a grid-connected BDFM under unbalanced grid voltage conditions

    , Article 2011 IEEE International Electric Machines and Drives Conference, IEMDC 2011, 15 May 2011 through 18 May 2011 ; May , 2011 , Pages 1647-1651 ; 9781457700613 (ISBN) Sotoodeh, P ; Seyed Mahdi Izadkhast ; Khosravi, H ; Oraee, H ; Sharif University of Technology
    2011
    Abstract
    This paper presents a mathematical model for Brushless Doubly-Fed Machine (BDFM) based on Stator Flux Orientation (SFO) in positive and negative reference frames under unbalanced grid voltage conditions. A negative controller is designed to eliminate the effects of unbalanced conditions on electrical torque. The model and controller performance during unbalanced conditions is validated by time domain simulation in MATLAB/Simulink  

    Stabilizing periodic orbits of the fractional order chaotic van der pol system

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010, Vancouver, BC ; Volume 8, Issue PARTS A AND B , 2010 , Pages 175-183 ; 9780791844458 (ISBN) Rahimi, M. A ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    2010
    Abstract
    In tins paper, stabilizing the unstable periodic orbits (UPO) in a chaotic fractional order system called Van der Pol is studied. Firstly, a technique for finding unstable periodic orbit in chaotic fractional order systems is stated. Then by applying tins technique to the van der Pol system, unstable periodic orbit of system is found. After that, a method is presented for stabilization of the discovered UPO based on theories stability of the linear integer order and fractional order systems. Finally, a linear feedback controller was applied to the system and simulation is done for demonstration of controller performance  

    Notes on integral performance indices in fractional-order control systems

    , Article Journal of Process Control ; Volume 20, Issue 3 , 2010 , Pages 285-291 ; 09591524 (ISSN) Tavazoei, M. S ; Sharif University of Technology
    2010
    Abstract
    Integral performance indices as quantitative measures of the performance of a system are commonly used to evaluate the performance of designed control systems. In this paper, it is pointed out that due to existence of non-exponential modes in the step response of a fractional-order control system having zero steady state error, integral performance indices of such a system may be infinite. According to this point, some simple conditions are derived to guarantee the finiteness of different integral performance indices in a class of fractional-order control systems. Finally, some numerical examples are presented to show the applicability of the analytical achievements of the paper  

    Design and assessment of variable-structure LQG PID multivariable controllers

    , Article Optimal Control Applications and Methods ; 2016 ; 01432087 (ISSN) Mousavi, H ; Nobakhti, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    Control Performance Assessment (CPA) and tuning of PID controllers are studied in this paper. We propose a framework for systematic analysis of the tradeoff between the structural complexity of the controller and its performance. As the measure of the controller performance, an LQG based index is used. The problem is augmented with an additional term which forces sparsity on the complexity of a decentralized PID controller. The desired complexity is controlled via a weighting parameter which determines the cost of each additional element (i.e., P, I, and D terms). The result is a decentralized multivariable PID controller in which the complexity of each loop controller is optimized such that... 

    Robust control of LVAD based on the sub-regional modeling of the heart

    , Article Scientia Iranica ; Volume 23, Issue 6 , 2016 , Pages 2934-2943 ; 10263098 (ISSN) Ravanshadi, S ; Jahed, M ; Sharif University of Technology
    Sharif University of Technology  2016
    Abstract
    Left Ventricular Assist Devices (LVAD) have received renewed interest as a bridge-to-transplantation as well as a bridge-to-recovery device. Ironically, reports of malfunction and complications have hindered the growth of this device. In particular, the main concern is LVAD's susceptibility to excessive backlash and suction as a result of ows that are either too low or high, respectively. This study utilizes a well-established physiological model of the cardiovascular system as a reliable platform to study a proposed adaptive robust controller for a rotary motor based LVAD which overcomes such shortcomings. Proposed controller performance is evaluated by comparing simulated natural heart... 

    Robust roll autopilot design to reduce couplings of a tactical missile

    , Article Aerospace Science and Technology ; Volume 51 , 2016 , Pages 142-150 ; 12709638 (ISSN) Rezazadeh Mohammadi, M ; Fathi Jegarkandi, M ; Moarrefianpour, A ; Sharif University of Technology
    Abstract
    The purpose of this work is to decrease coupling effects of a tactical missile by designing a robust autopilot for its roll channel. In tactical STT missiles due to control strategy, in order to execute acceleration commands, roll angular velocity should be kept close to zero. Generally, in the design of autopilot for many of tactical missiles the inter influences of channels is neglected. However, three channels of the missile impact each other in different ways including kinematic, inertia and aerodynamic couplings. Aerodynamic coupling is a dominant in roll channel dynamics appearing as induced and control cross coupling roll moments. In this paper first the coupling terms are modeled... 

    Design and assessment of variable-structure LQG PID multivariable controllers

    , Article Optimal Control Applications and Methods ; Volume 38, Issue 4 , 2017 , Pages 634-652 ; 01432087 (ISSN) Mousavi, H ; Nobakhti, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2017
    Abstract
    Control Performance Assessment (CPA) and tuning of PID controllers are studied in this paper. We propose a framework for systematic analysis of the tradeoff between the structural complexity of the controller and its performance. As the measure of the controller performance, an LQG based index is used. The problem is augmented with an additional term which forces sparsity on the complexity of a decentralized PID controller. The desired complexity is controlled via a weighting parameter which determines the cost of each additional element (i.e., P, I, and D terms). The result is a decentralized multivariable PID controller in which the complexity of each loop controller is optimized such that... 

    New robust control method applied to the locomotion of a 5-link biped robot

    , Article Robotica ; 2019 ; 02635747 (ISSN) Mehdi Kakaei, M ; Salarieh, H ; Sharif University of Technology
    Cambridge University Press  2019
    Abstract
    This paper proposes a new design of robust control combining feedback linearization, backstepping, and sliding mode control called FLBS applied to the locomotion of five-link biped robot. Due to the underactuated robot's model, the system has a hybrid nature, while the FLBS control can provide a stabilized walking movement even with the existence of large disturbances and uncertainties by implementing smooth chatter-free signals. Stability of the method is proven using the Lyapunov theorem based on the hybrid zero dynamics and Poincaré map. The simulations show the controller performance such as robustness and chatter-free response in the presence of uncertainty and disturbance. © 2020... 

    New robust control method applied to the locomotion of a 5-link biped robot

    , Article Robotica ; 2019 ; 02635747 (ISSN) Mehdi Kakaei, M ; Salarieh, H ; Sharif University of Technology
    Cambridge University Press  2019
    Abstract
    This paper proposes a new design of robust control combining feedback linearization, backstepping, and sliding mode control called FLBS applied to the locomotion of five-link biped robot. Due to the underactuated robot's model, the system has a hybrid nature, while the FLBS control can provide a stabilized walking movement even with the existence of large disturbances and uncertainties by implementing smooth chatter-free signals. Stability of the method is proven using the Lyapunov theorem based on the hybrid zero dynamics and Poincaré map. The simulations show the controller performance such as robustness and chatter-free response in the presence of uncertainty and disturbance. © 2020... 

    Direct synthesis of fixed-order multi-objective controllers

    , Article Optimal Control Applications and Methods ; Volume 41, Issue 3 , 2020 , Pages 849-865 Abdolahi, A ; Babazadeh, M ; Nobakhti, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2020
    Abstract
    This paper introduces a new methodology for the design of fixed-order multi-objective output feedback controllers. The problem comprises a set of linear matrix inequalities and an additional rank constraint. The primary idea is to classify convex subsets of the set of rank constrained matrices in such formulations, based on which two noniterative and relatively fast methods are developed. The proposed methods require solving a convex optimization problem at each step and can be applied with any weighted summation of design objectives such as (Formula presented.) performance, (Formula presented.) performance, passivity, and regional pole assignment. Several benchmark systems with performance... 

    Planing craft control using pneumatically driven trim tab

    , Article Mathematics and Computers in Simulation ; Volume 178 , December , 2020 , Pages 439-463 Jokar, H ; Zeinali, H ; Tamaddondar, M. H ; Sharif University of Technology
    Elsevier B. V  2020
    Abstract
    Dynamic instabilities are quite common in planing crafts. This study deals with the elimination of one type of dynamic instabilities known as porpoising. The controller device is a pneumatically driven trim tab that applied to the transom of the boat. The governing dynamic equations of the planing craft and the pneumatically driven system are derived. The stability analysis of the system is carried out and porpoising instability is shown under some conditions. A dual control scheme consisting of the actuator control subsystem (inner control subsystem) and the planing craft (outer control subsystem) is proposed in order to control the planing craft from porpoising instability. Since the... 

    New robust control method applied to the locomotion of a 5-link biped robot

    , Article Robotica ; Volume 38, Issue 11 , January , 2020 , Pages 2023-2038 Kakaei, M. M ; Salarieh, H ; Sharif University of Technology
    Cambridge University Press  2020
    Abstract
    This paper proposes a new design of robust control combining feedback linearization, backstepping, and sliding mode control called FLBS applied to the locomotion of five-link biped robot. Due to the underactuated robot's model, the system has a hybrid nature, while the FLBS control can provide a stabilized walking movement even with the existence of large disturbances and uncertainties by implementing smooth chatter-free signals. Stability of the method is proven using the Lyapunov theorem based on the hybrid zero dynamics and Poincaré map. The simulations show the controller performance such as robustness and chatter-free response in the presence of uncertainty and disturbance. Copyright ©... 

    L1 Adaptive integrated guidance and control for flexible hypersonic flight vehicle in the presence of dynamic uncertainties

    , Article Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering ; Volume 235, Issue 8 , 2021 , Pages 1521-1531 ; 09596518 (ISSN) Khankalantary, S ; Rezaee Ahvanouee, H ; Mohammadkhani, H ; Sharif University of Technology
    SAGE Publications Ltd  2021
    Abstract
    In this article, an integrated guidance and control design method for general nonlinear flexible hypersonic flight vehicles in the presence of dynamic uncertainties based on the (Formula presented.) adaptive state feedback control approach is presented. Initially, the 6-degree-of-freedom integrated guidance and autopilot dynamic model is organized using the combination of flexible uncertain hypersonic flight vehicle dynamic model and hypersonic flight vehicle-target relative motion model whereas aerodynamic and model uncertainties, cross-coupling effects, and disturbances are considered. The proposed integrated guidance and control method based on (Formula presented.) adaptive control scheme...