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output-feedback
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Maximal bound for output feedback gain in stabilization of fixed points of fractional-order chaotic systems
, Article Journal of Computational and Nonlinear Dynamics ; Volume 6, Issue 3 , February , 2011 ; 15551415 (ISSN) ; Sharif University of Technology
2011
Abstract
This paper deals with the problem of stabilizing the unstable fixed points of a class of fractional-order chaotic systems via using static output feedback. At first, a static output feedback controller designed to stabilize a fixed point of a fractional-order chaotic system is considered. Then, the maximal allowable perturbation bound around the nominal value of the output feedback gain of the designed controller, such that the stability of the intended fixed point in the closed-loop system is guaranteed, is analytically determined. Also, some numerical examples are presented to confirm the validity of the analytical results of the paper
Observer-free control of satellite attitude using a single vector measurement
, Article IEEE Transactions on Aerospace and Electronic Systems ; Vol. 50, issue. 3 , 2014 , pp. 2070-2081 ; ISSN: 00189251 ; Namvar, M ; Sharif University of Technology
Abstract
The existing methods in attitude control of satellites are based on using the estimate of satellite attitude, which is usually generated by using multiple vector measurements. In this paper we propose an output feedback controller that directly uses a single vector measurement and does not use an attitude estimator. The output feedback gain is computed by solving a generalized Riccati differential equation (GRDE). The existence of a solution to the GRDE depends on a uniform controllability condition
Output feedback control of satellite attitude using a single vector measurement
, Article Proceedings of the IEEE Conference on Decision and Control, 10 December 2012 through 13 December 2012, Maui, HI ; 2012 , Pages 490-495 ; 01912216 (ISSN) ; Namvar, M ; Sharif University of Technology
2012
Abstract
The existing methods in attitude control of satellites are based on employing the estimate of satellite attitude which is usually generated by using multiple vector measurements. In this paper we propose an output feedback control law that directly uses a single vector measurement and gyro, and without any need for estimating the satellite attitude. The output feedback gain is computed by solving a generalized Riccati time varying differential equation. We assume the moment-of-inertia matrix of satellite is unknown. The controller guarantees asymptotic convergence of the attitude to its desired value. A realistic simulation is presented where a magnetometer is used to provide the single...
Linear output feedback control of a three-pole magnetic bearing
, Article IEEE/ASME Transactions on Mechatronics ; Vol. 19, issue. 4 , 2014 , pp. 1323-1330 ; ISSN: 10834435 ; Behzad, M ; Salarieh, H ; Mehdigholi, H ; Sharif University of Technology
Abstract
The design and implementation of linear and nonlinear control methods for a three-pole active magnetic bearing (AMB) is presented in this paper. It is shown that the system has nearly linear dynamics by adding a bias to coil currents. A decentralized PID feedback law and an integral sliding mode controller are proposed and the unknown state variables of the system are estimated by the Kalman filter. The optimal gains of the linear controller are determined by the LQG technique. To evaluate the effectiveness of the proposed controllers, they are implemented on an experimental setup. The experimental results show that the proposed methods can effectively stabilize the three-pole AMB. The...
Partial integrity of unstable LTI systems
, Article 24th Mediterranean Conference on Control and Automation, 21 June 2016 through 24 June 2016 ; 2016 , Pages 1302-1306 ; 9781467383455 (ISBN) ; Nobakhti, A ; Babazadeh, M ; MCA ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
This paper considers the Integral Stabilizability (IS) and partial integrity of Linear Time Invariant (LTI) systems with an unstable sub-system. The main contribution of the paper is to show that if the unstable sub-system can be stabilized by means of output feedback, then one obtains an integrity condition which is actually equivalent to that of open-loop stable systems, with two additional assumptions. This means the condition may be evaluated solely on the basis of plant information and does not rely on the knowledge of the values of the controller parameters
Structured design of an integrated subscriber line interface system and circuit
, Article Proceedings of the 2003 IEEE International Symposium on Circuits and Systems, Bangkok, 25 May 2003 through 28 May 2003 ; Volume 2 , 2003 , Pages II284-II287 ; 02714310 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
2003
Abstract
A structured design of Subscriber Line Interface System and Circuit will be described. A high level synthesis allows extracting overall system and circuit requirements to satisfy the desired specifications, standards, and a robust implementation. For this purpose, first the output driving stage will be analyzed and then, dc, ac, and longitudinal balance feedbacks will be considered. Then based on extracted system specifications, optimum circuit design of line-driver will be described. High-level design of line-driver as the most important circuit block optimized for stability, accuracy, area, and power dissipation will be elaborated
A very low power CMOS, 1.5V, 2.5GHz prescaler
, Article 2002 45th Midwest Symposium on Circuits and Systems, Tulsa, OK, 4 August 2002 through 7 August 2002 ; Volume 3 , 2002 , Pages III378-III380 ; Sharif University of Technology
2002
Abstract
A very low power CMOS, 1.5V, 2.5GHz prescaler was designed. Implemented in 0.25u standard CMOS technology, this prescaler can operate up to 3GHz range. The prescaler consists of three delay flip flops (DFF) that work synchronously with RF sinusoidal clock and divides by 4 or 5 according to control signal
Genetic approach to pole placement by static output feedback
, Article 2002 Congress on Evolutionary Computation, CEC 2002, Honolulu, HI, 12 May 2002 through 17 May 2002 ; Volume 2 , 2002 , Pages 1174-1179 ; 0780372824 (ISBN); 9780780372825 (ISBN) ; Kuchakkhani, S ; Sharif University of Technology
IEEE Computer Society
2002
Abstract
In this paper, a new approach for solving the problem of pole assignment, using static output feedback, has been proposed. The proposed approach is based on genetic algorithm where it can place all the closed-loop poles at desired locations with a high accuracy, provided that there exists a solution to the problem. It is also shown that how some known difficulties of static output feedback like order of system, multiplicity of the desired poles and the need for having closed-loop poles to be distinct or different from the open loop poles have been solved. Numerical examples at the end of the paper illustrate the applicability and the performance of the proposed method. © 2002 IEEE
Global Estimation and Control of Rigid-body Attitude and Position Using Single Landmark Measurement
, M.Sc. Thesis Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
The purpose of determining orientation and position of a rigid-body is specifying its attitude and position with respect to a specified reference frame in order to using in controller. Since there is no sensor that can directly measures the attitude and position, we have to estimate those variables by observers. In this thesis we derive a new and explicit neccesary and sufficient condition for observability of the rigid-body kinematic equation. Also we propose a new observer for estimating the attitude and position of the rigid-body. The special feature of the proposed estimator is that it use only a single landmark and is globally and exponentially stable. In the next step we study the...
Attitude Control of Satellite Using a Single Vector Measurement and Gyro
, Ph.D. Dissertation Sharif University of Technology ; Namvar, Mehrzad (Supervisor)Adaptive fuzzy approach for H∞ temperature tracking control of continuous stirred tank reactors
, Article Control Engineering Practice ; Volume 16, Issue 9 , September , 2008 , Pages 1101-1108 ; 09670661 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
2008
Abstract
In this paper, an adaptive fuzzy temperature controller is proposed for a class of continuous stirred tank reactors (CSTRs) based on input-output feedback linearization. Since for control implementation concentrations of all species are needed, based on the observability concept, a fuzzy logic system is used to estimate the concentration dependent terms and other unknown system parameters in the control law, using temperature measurements. It has been shown that the H∞ tracking control performance with a prescribed attenuation level is achieved, by using the proposed controller. Finally the effectiveness of the proposed controller has been demonstrated by applying it to a benchmark chemical...
Application of neural networks and state space averaging to a DC/DC PWM converter in sliding mode operation
, Article IECON Proceedings (Industrial Electronics Conference) ; Volume 1 , 2000 , Pages 172-177 ; Nasiri, M. R ; Agah, A ; Sharif University of Technology
IEEE Computer Society
2000
Abstract
A novel output feedback neural controller is presented for the implementation of sliding mode control of DC/DC converters. The controller, which consists of a multilayer perceptron, has been trained so as to be robust for large variations of system parameters and state variables. Fast dynamic behavior is the other main advantage of the proposed controller, which allows realization of all the beneficial features of sliding mode control technique. Other advantages of the controller are simplicity and low cost. Computer simulations are carried out to investigate the effectiveness of the controller in voltage regulation for a relatively complex topology such as a Cuk converter. Simulation...
Output feedback adaptive control of a class of nonlinear discrete-time systems with unknown control directions and preceded by hysteresis
, Article International Journal of Control ; Volume 88, Issue 11 , Jun , 2015 , Pages 2412-2422 ; 00207179 (ISSN) ; Ghaderi, A ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
This paper considers the output feedback adaptive controller design problem for a class of discrete-time nonlinear systems in output feedback form with unknown control directions and preceded by unknown hysteresis. The problem of lacking in a-priori knowledge on the control directions and unknown hysteresis are solved by using the discrete Nussbaum gain and Prandtl-Ishlinskii model, respectively. The system is transformed into the form of a nonlinear auto regressive moving average (NARMA) model to construct an output feedback control. To overcome the noncausal problem in the control design, future output prediction laws and parameter update laws with the dead-zone technique are constructed...
Fixed Order Controller Design Via Convex Optimization
, M.Sc. Thesis Sharif University of Technology ; Nobakhti, Amin (Supervisor)
Abstract
In this thesis we introduce a new methodology to solve the problem of multi-objective control design of linear output-feedback with a constraint on the order of controller. This problem can be formulated as a set of linear matrix inequalities and an additional rank constraint. This constraint is highly non-convex and makes this optimization problem NP-hard. The proposed methodology results in methods which are multi-step and in each step a convex optimization problem shall be solved. This methodology can consider any combination of different design objectives such as H2 performance, H1 performance, passivity and regional pole assignment. In the development of described methodology, a...
Analysis and Design of Adaptive Control Systems Based on Contraction Theory
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohammad Saleh (Supervisor)
Abstract
This thesis deals with output feedback control design, adaptive output feedback control design, and adaptive actuator compensation for input-affine nonlinear systems on the basis of contraction metrics. In Section I, some necessary backgrounds on Riemannian geometry and contraction analysis are presented. In Section II, firstly, an observer for the considered class of nonlinear systems is proposed. Then, it is shown that by combining the introduced observer with state-feedback controllers in a suitable way, output tracking can be achieved. Moreover, the obtained results are extended to be used for adaptive output feedback stabilization of uncertain nonlinear systems. The introduced...
Functional observer design with application to pre-compensated multi-variable systems
, Article 2015 IEEE Conference on Control and Applications, CCA 2015 - Proceedings, 21 September 2015 through 23 September 2015 ; 2015 , Pages 620-625 ; 9781479977871 (ISBN) ; Mohajerpoor, R ; Abdi, H ; Nahavandi, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Partial state estimation of dynamical systems provides significant advantages in practical applications. Likewise, pre-compensator design for multi variable systems invokes considerable increase in the order of the original system. Hence, applying functional observer to pre-compensated systems can result in lower computational costs and more practicability in some applications such as fault diagnosis and output feedback control of these systems. In this note, functional observer design is investigated for pre-compensated systems. A lower order pre-compensator is designed based on a H2 norm optimization that is designed as the solution of a set of linear matrix inequalities (LMIs). Next, a...
Observer-Based Output Feedback Linearization Control with Application to HIV Dynamics
, Article Industrial and Engineering Chemistry Research ; Volume 54, Issue 10 , January , 2015 , Pages 2697-2708 ; 08885885 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
American Chemical Society
2015
Abstract
This paper presents the feedback linearization control of HIV infection. A multi-input multi-output (MIMO) dynamic nonlinear HIV infection model for this purpose has been used. For this purpose, three widely used drugs are considered. A Luenberger-like nonlinear observer (LNO) is designed for estimation of unavailable states. To minimize the side effects of drugs, the concentration of ZDV which has the highest side effect is fixed to a minimum value and the external controllers parameters are obtained by maximizing an objective function. In the control design, limitations on drug consumption and unavailability of all states are taken into account. The closed-loop stability has been...
Flexible formation of multiple car-like robots with respect to a dynamic environment
, Article Scientia Iranica ; Volume 23, Issue 4 , 2016 , Pages 1844-1855 ; 10263098 (ISSN) ; Sharif University of Technology
Sharif University of Technology
Abstract
This paper attempts to give a perspective on decentralized formation control of multiple car-like mobile robots using local information and formation changes in a dynamic environment having several obstacles. In addition, for every mobile robot, it takes physical dimensions, mass, moment of inertia, movement constraints, and saturation of actuators into account. This study makes use of Input/Output Feedback Linearization Method to control each robot. Hence, hierarchical leader-follower based algorithm is employed to control the group formation. To avoid collision between robots and obstacles, and of robots with each other, local artificial potential fields are addressed. The group can change...
Observer based feedback control of a biodynamical model of tumor growth with sampled measurements
, Article 2016 European Control Conference, ECC 2016, 29 June 2016 through 1 July 2016 ; 2017 , Pages 2423-2428 ; 9781509025916 (ISBN) ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
This paper deals with the cancer treatment scheduling via observer-based feedback control of a tumor growth biodynamical model. An experimental nonlinear model is utilized to design a feedback controller. This model was validated by a pharmacological study on xenograft models obtained by transplantation of colon carcinoma cell lines in athymic mice. Input-output feedback linearization approach is used to linearize the nonlinear model of the system and design a control law. It is assumed that tumor weight can be measured in definite intervals. So a continuous-discrete observer is designed to estimate states of the system based on discrete sampled data which are tumor weight in this case. To...
Direct synthesis of fixed-order multi-objective controllers
, Article Optimal Control Applications and Methods ; Volume 41, Issue 3 , 2020 , Pages 849-865 ; 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...