Search for: robust-control
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    Control of series resonant converter with robust performance against load and power circuit components uncertainties

    , Article PEDSTC 2010 - 1st Power Electronics and Drive Systems and Technologies Conference, 17 February 2010 through 18 February 2010, Tehran ; 2010 , Pages 122-128 ; 9781424459728 (ISBN) Mohammadpour, A ; Mokhtari, H ; Zolghadri, M. R ; Sharif University of Technology
    Robust performance controller design for duty-cycle controlled series resonant converter is proposed in this paper. The uncertainties of the converter are analyzed with load variation and power circuit components tolerances are taken into consideration. Additionally, a nominal performance H ∞ controller is designed. Closed-loop system is simulated and simulation results of robust controller are compared with H∞ nominal performance controller  

    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
    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... 

    H ∞ and μ synthesis control of virtual structure satellites formation flying

    , Article International Journal of Dynamics and Control ; Volume 5, Issue 3 , 2017 , Pages 741-755 ; 2195268X (ISSN) Hassani, A ; Saghafi, F ; Pasand, M ; Sharif University of Technology
    Recent developments in the space industry and the great tendency to define efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of multiple satellites control methods is the subject of the present paper. In this paper, two linear robust control strategies are applied to position control system of certain satellites in the virtual structure formation flight. The proposed controllers are designed considering different parametric uncertainties such as semimajor axis and eccentricity changes as well as some disturbances like second term of gravitational acceleration function (j2) and drag... 

    Development of H ∞ -Robust control strategy for drying process in fluidized food bed dryers

    , Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 43, Issue 1 , 2019 , Pages 87-101 ; 22286187 (ISSN) Moradi, H ; Ghabraei, S ; Vossoughi, G ; Sharif University of Technology
    Springer International Publishing  2019
    Moisture control of food products is of great importance in drying processes. Improving the dryer control system results in consistent production and reduction in energy consumption. In this paper, a state observer is used to estimate the moisture content and other state variables online. Estimated states are used in a control system including the regulator for disturbance rejection and robust controller for tracking objective. Since the bed dryer mechanism is a multivariable complex system associated with various uncertainties, a realistic uncertain model is considered. Moisture content and temperature of tea leaves (or other food products) are controlled at desired set points by... 

    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
    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... 

    Dynamic Analysis, Simulation and Control of a Single-Axel Two-Wheeled Vehicle

    , M.Sc. Thesis Sharif University of Technology Ayatollahzadeh Shirazi, Hossein (Author) ; Vossoughi, Gholamreza (Supervisor)
    In the recent decade many researches have been done on optimizing urban traffic. The invention of single-axel two-wheeled vehicle -which is also known as Segway- is toward this goal. This vehicle was invented in 2002 by Dean Kaman. The Segway doesn’t need fossil fuels, occupies very little space, is very convenient to use and its parallel wheel configuration makes it compact enough to be maneuvered through most spaces. After the invention of the Segway, two wheel balancing robots has attracted more attention and in recent researches Passenger-carrying capacity has been considered. In this project, by taking into account passenger-carrying capacity and possibility of wheel slippage, an exact... 

    Stability and Performance Analysis of Human-Machine Interaction in Haptic Systems

    , M.Sc. Thesis Sharif University of Technology Tajaddodianfar, Farid (Author) ; Ahmadian, Mohammad Taghi (Supervisor) ; Vossoughi, Gholamreza (Supervisor)
    Transparency is a measure of performance in haptic devices. In order to improve transparency and reduce the difference between the impedance transmitted to the user and the target impedance it is necessary to compensate for the dynamics of the haptic device. Due to stability reasons improvement of transparency is limited. Passivity as a stability criterion has been used widely in design and analysis of haptic devices. Since passivity is a conservative criterion, it acts as an obstacle in improving transparency of the haptic interfaces. In this project instead of passivity, robust stability of the interaction is studied in the presence of parametric uncertainties due to variations in user... 

    Robust Control of Satellites Formation Flying

    , M.Sc. Thesis Sharif University of Technology Hassani, Ali (Author) ; Saghafi, Fariborz (Supervisor)
    Recent developments in space industry and the great tendency for definition of efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of the multiple satellite control methods is the subject of the present project. In this project, the governing equations of motion of satellite formation flight are developed. Based on this development, it is shown that the satellite linear equations of motion like many other linear system presentations, can not sufficiently model the real system. Therefore, some of the most famous uncertainties in space dynamics such as semimajor axis and eccentricity... 

    Design of Robust Controller for Depth of Anesthesia

    , M.Sc. Thesis Sharif University of Technology Hosseinzadeh, Mahdi (Author) ; Sadati, Nasser (Supervisor)
    Automatic control of depth of anesthesia is an important problem in biomedical engineering. The main challenging problem in anesthesia automation is inter-patients differences which is referred to as uncertainty and is crucial in robust controller design. One of the most appropriate tools in designing robust controllers is H_∞ concept. Furthermore, H_2 concept is used to reject the measurement noise which is unavoidable in practical cases. In this project we use mixed H_2/H_∞ concept to design robust controller for depth of anesthesia. Multi-model controller is another approach to design robust controller for depth of anesthesia, which reject measurement noise and also cover the... 

    Robust control strategy for HBV treatment: Considering parametric and nonparametric uncertainties

    , Article Control Applications for Biomedical Engineering Systems ; 2020 , Pages 127-147 Aghajanzadeh, O ; Sharifi, M ; Falsafi, A ; Sharif University of Technology
    Elsevier Inc  2020
    Hepatitis is one of the most perilous viral infectious diseases and many people suffer from it all around the world. In particular, hepatitis B is a terribly dangerous disease which may cause severe liver damage or cancer if it is not treated. Recently, several dynamic models have been developed from experimental studies for describing such diseases mathematically. The certainty of these dynamics models is questionable in realistic treatment processes. Thus, the modeling uncertainties should be considered in the dynamics, which necessitates employing robust control strategies capable to overcome these uncertainties. Accordingly, in this research, a control strategy is developed in order to... 

    RCCT: Robust clustering with cooperative transmission for energy efficient wireless sensor networks

    , Article International Conference on Information Technology: New Generations, ITNG 2008, Las Vegas, NV, 7 April 2008 through 9 April 2008 ; 2008 , Pages 761-766 ; 0769530990 (ISBN); 9780769530994 (ISBN) Ghelichi, M ; Jahanbakhsh, S. K ; Sanaei, E ; Sharif University of Technology
    Data gathering is a common but critical operation in many applications of wireless sensor networks. Innovative techniques that improve energy efficiency to prolong the network lifetime are highly required. Clustering is an effective topology control approach in wireless sensor networks, which can increase scalability and lifetime. These networks require robust wireless communication protocols that are energy efficient and provide low latency. In this paper, we develop and analyze an efficient cooperative transmission protocol with robust clustering (RCCT) for sensor networks that considers a fault-tolerant and energy-efficient distributed clustering with minimum overhead. RCCT distributes... 

    On secure consensus information fusion over sensor networks

    , Article 2007 IEEE/ACS International Conference on Computer Systems and Applications, AICCSA 2007, Amman, 13 May 2007 through 16 May 2007 ; 2007 , Pages 108-115 ; 1424410312 (ISBN); 9781424410316 (ISBN) Kefayati, M ; Talebi, M. S ; Rabiee, H. R ; Khalaj, B. H ; Sharif University of Technology
    In this work we have examined the problem of consensus information fusion from a novel point of view, challenging the fundamental assumption of mutual trust among the fusion parties. In quest for a method to make information fusion possible while preserving the mutual confidentiality and anonymity of the fused information even in case of collusion of the malicious nodes, we propose the Blind Information Fusion Framework (BIFF). In BIFF, which is a secure information fusion framework, the nodes are not aware of the actual information they are processing, yet converging to the intended result(s). We formulate BIFF according to the anonymization transform and discuss its robustness against... 

    Applying robust predictive functional control to mass transmission benchmark

    , Article EUROCON 2005 - The International Conference on Computer as a Tool, Belgrade, 21 November 2005 through 24 November 2005 ; Volume I , 2005 , Pages 294-297 ; 142440049X (ISBN); 9781424400492 (ISBN) Soltanzadeh, A ; Haeri, M ; Sharif University of Technology
    IEEE Computer Society  2005
    Predictive functional controller originally developed based on a first order reference model. In this paper the related equation of the predictive functional control is derived for an arbitrary reference model and then a simple approach to tune different parameters of the controller is examined by applying the controller on a benchmark problem. Finally, the robustness of the design is improved using the so called Youla parameterization approach. © 2005 IEEE  

    Hierarchical optimal robust load-frequency control for power systems

    , Article IET Generation, Transmission and Distribution ; Volume 6, Issue 4 , 2012 , Pages 303-312 ; 17518687 (ISSN) Rahmani, M ; Sadati, N ; Sharif University of Technology
    In this study, a hierarchical optimal robust controller is presented for the power system load-frequency control problem. In this approach, the multi-area power system is first decomposed into several sub-systems (areas). Then by using a two-level control strategy, the overall optimal solution is obtained. At the first level, the optimal control of each area is obtained with respect to local information and also considering interactions coming from other areas. At the second level, by using a coordination strategy, the local controllers will converge to global solution and optimal robust controller is achieved. This approach is applicable to both single-area and multi-area interconnected... 

    Design and performance analysis of a transparent force control strategy for an exoskeleton

    , Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 563-568 ; 9781467372343 (ISBN) Rashidi, A ; Zibafar, A ; Khezrian, R ; Vossoughi, G ; Sharif University of Technology
    Exoskeleton robots are developed for human rehabilitation and power augmentation. Human and robot interaction is an important issue involved with these robots. In this paper, the interaction force reduction is considered leading to the transparency of a lower limb exoskeleton during swing phase of walking. Achieving this goal, a robust Lyapunov based motion control method has been developed. The desired reference signals for motion control are generated using a direct force control approach. Robot accelerations are estimated by an observer to be employed in the control loop. An adaptation procedure has been proposed for the bound estimation of uncertainties. As part of assumptions, the... 

    Robust control of robotic manipulators based on -synthesis

    , Article 17th International Congress on Sound and Vibration 2010, ICSV 2010, Cairo, 18 July 2010 through 22 July 2010 ; Volume 1 , 2010 , Pages 525-532 ; 9781617822551 (ISBN) Moradi, H ; Bakhtiari Nejad, F ; Sadighi, M ; Ahmadian, M. T ; Sharif University of Technology
    A robotic manipulator is modelled as a cantilever rotating Euler-Bernoulli beam. Two dynamic transfer functions are derived to describe beam tip motion and angular rotation in terms of the desired angular rotation. Torque disturbance, imprecision in the payload mass, unknown properties of the manipulator link are sources of uncertainty. The objective is to achieve a desired angular rotation while the vibration of manipulator tip is suppressed. The control input of the system is an external driving torque. The -synthesis control approach is used and an H optimal robust controller is developed based on the DK-iteration algorithm. Results show that the designed controller guarantees the robust... 

    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) Jahromi Shirazi, M ; Vatankhah, R ; Boroushaki, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    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... 

    Nonlinear robust adaptive sliding mode control of influenza epidemic in the presence of uncertainty

    , Article Journal of Process Control ; Volume 56 , 2017 , Pages 48-57 ; 09591524 (ISSN) Sharifi, M ; Moradi, H ; Sharif University of Technology
    Elsevier Ltd  2017
    In this paper, a nonlinear robust adaptive sliding mode control strategy is presented for the influenza epidemics in the presence of model uncertainties. The nonlinear epidemiological model of influenza with five state variables (the numbers of susceptible, exposed, infected, asymptomatic and recovered individuals) and two control inputs (vaccination and antiviral treatment) is considered. The objective of the proposed controller is decreasing the number of susceptible and infected humans to zero by tracking the desired scenarios. As a result of this decreasing, the number of exposed and asymptomatic individuals is also decreased and converged to the zero. Accordingly, it is shown that the... 

    Robust control of a class of fractional order plants in the presence of pole uncertainty

    , Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 881-886 ; 9781538649169 (ISBN) Basiri, M. H ; Tavazoei, M. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    In recent years some approaches for robust control of plants with uncertainty in their poles have been suggested. Recently a new approach for tuning controllers has been introduced that can preserve phase margin in desirable value despite large variations in location of one of the poles and also it is able to provide required gain crossover frequency in the nominal case. In this paper by benefiting from this approach, a fractional order proportional derivative controller is introduced to control the plants with fractional order transfer function with uncertainty in their poles with order in the range (1, 2). Also, sufficient conditions on design specifications and plant parameters for... 

    Adaptive robust control of fractional-order swarm systems in the presence of model uncertainties and external disturbances

    , Article IET Control Theory and Applications ; Volume 12, Issue 7 , 2018 , Pages 961-969 ; 17518644 (ISSN) Naderi Soorki, M ; Tavazoei, M. S ; Sharif University of Technology
    Institution of Engineering and Technology  2018
    This study investigates the asymptotic swarm stabilisation of fractional-order swarm systems in the presence of two different kinds of model uncertainties and external disturbances while the upper bound of the uncertainties is a linear function of pseudo-states norms with unknown coefficients. To this end, first a fractional-integral sliding manifold is constructed and then an adaptive-robust sliding mode controller is designed to guarantee the asymptotic swarm stability in a fractional-order linear time-invariant swarm system. The stability analysis of the proposed control system is done based on the Lyapunov stability theorem. Using the proposed controller, the coefficients of the upper...