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Home>Products>Journal and Reviews>I.RE.A.CO.>Latest issue International Review of Automatic Control (Theory and Applications) - July 2008 - Papers
International Review of Automatic Control - Papers
by B. Larroque, F. Noureddine, F. Rotella Vol. 1. n. 2, pp. 132-142
Abstract - This paper provides a procedure for the design of a reduced order observer of a state linear functional for a linear time-invariant system. The case, defined in [1], where the observer order p is given by the number m of single independent linear functionals to be observed, is called in this paper the minimum case where p = m. The minimum case is revisited and numerically simplified. The aim of this paper is to extend the minimum case to the case where m < p < n-l, named minimal case. A constructive procedure is given to design the linear functional observer. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Linear functional observers, linear time-invariant systems, generalized inverse.
by C. Mnasri, M. Gasmi Vol. 1. n. 2, pp. 143-152
Abstract - In This paper, three dominating limitations of the classic sliding mode control are raised with the proposal of a new adaptive fuzzy full-order sliding Mode control scheme. The first limitation, the reaching mode existence, has been overcame by a particular choice of the sliding surface allowing to the system trajectory to be initially in sliding mode. The second one which is the information need of the upper bounds of uncertainties has been solved by the use of the adaptive technique. The main drawback of sliding mode, which is the chattering phenomenon, is eliminated by the incorporation of a fuzzy logic inference mechanism. The mathematical proof of the proposed methodology in sense of Lyapunov stability for model-reference control of uncertain systems is established. The robustness of stability, the tracking performance and the chattering removal are guaranteed. These performances are validated through the simulation of a two-degree-of-freedom robotic manipulator. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Adaptive Technique, Chattering, Fuzzy Logic, Robustness, Matched Uncertainties, Robot manipulator, Sliding Mode, Tracking Performance.
Vol. 1. n. 2, pp. 153-158
Abstract - This paper describes the implementation of Gaussian process (GP) based Discrete-time Sliding Mode Control (DSMC). A Gaussian process is a random function fully characterized by its mean and co-variance functions. Sliding-mode control (SMC) is one of the powerful techniques to analyze nonlinear and uncertain systems. The SMC has the properties of insensitivity to the unpredictable external disturbances and modeling errors. This proposed method ensures for any bounded initial conditions and uncertainties the controller steers the system states to the sliding manifold. A controller trained using Gaussian Process is used to implement DSMC. The simulation results demonstrate the advantages of the proposed controller. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Gaussian process model, Nonlinear systems, discrete-time sliding mode control.
Vol. 1. n. 2, pp. 159-168
Abstract - In this paper we propose an approach based on an initial controller for Youla parameterization defined by a mixed LQR/H∞ optimization. Moreover, the choices of the weighting coefficients of this initial controller have a great impact on the satisfaction of the required specifications of the system and its performances. To make the optimization problem always convex it is necessary to choose a convex combination of the two initial controllers. Our objective is to design a LQR/H∞ controller stabilizing the system with defined specifications in both time and frequencies domain via LMI optimization for an multi-objective optimization of the output feedback design in discrete time. Another objective of this work is to reduce the LMI conservatism. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Youla Parameter, LMI Optimization, LQR, H control, Multiobjective control.
Vol. 1. n. 2, pp. 169-176
Abstract - A predictive control algorithm for non-linear process based on the Generalized Predictive Control (GPC) algorithm with the Takagi-Sugeno, TS, fuzzy modeling approach is proposed. In the controller design, the online solution procedure is carried out using a two layered iterative optimization process. At the lower layer, local control policies are defined to minimize prediction errors for each subsystem arising in the TS model. The overall near optimum is then sought through coordinating the subsystems to attain an overall minimum prediction error at the upper layer. The performance of the fuzzy GPC approach is demonstrated with two simulations examples. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Fuzzy logic generalized predictive control, decomposition-coordination, and nonlinear systems.
Vol. 1. n. 2, pp. 177-183
Abstract - This paper presents a model-based technique for fault detection and isolation (FDI) of actuators of a benchmark which schematizes a hydraulic process made up of three tanks. Takagi Sugeno’s model approach is used for describing the dynamic of the system. In the same way, the fuzzy membership functions used for constructing Takagi and Sugeno’s model are combined with local unknown input observers to form robust fuzzy observer. Sufficient conditions for the existence of this fuzzy observer are derived. The stability as well as eigen-value constraints conditions are presented and solved in the LMI framework. For the observer gives a good estimation without amplifying noise and with a convergence faster than the dynamic of the system a eigen-value assignment is necessary. Robust residual signals, generated by these fuzzy observers robust to unknown inputs are dedicated to supervise actuators. These residuals are sensitive to faults acting on one actuator and are also insensitive to faults on the others by considering faults such unknown disturbances. This permits to carry out directly the isolation of the faulty actuator. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: FDI, LMI Approach, Nonlinear System, T-S Fuzzy Model, Unknown Input Fuzzy Observers, Quadratic Stability.
Vol. 1. n. 2, pp. 184-191
Abstract - Electrical action of higher performance of permanent magnet synchronous motors (PMSM) requires advanced strategies related to complex dynamic behaviour of these machines. In this paper, we propose a sliding mode technique to control the field-oriented Permanent magnet synchronous machine. The use of the nonlinear sliding mode method provides very good performance for motor operation and robustness of the control law despite the external/internal perturbations. Simulation results are given to highlight the performances of the proposed control technique under load disturbances and parameter uncertainties. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: PMSM, motor drives, robustness, sliding mode control.
Vol. 1. n. 2, pp. 192-199
Abstract - This paper presents a detailed design of an adaptive nonlinear controller applied to a three-phase permanent-magnet synchronous motor. The designed controller combines the nonlinear Input-Output linearization technique with linear adaptive control techniques. It takes into account the uncertainties in the stator inductance and the rotor moment of inertia which are difficult to measure with accuracy in practice. The stability of the closed-loop system is ensured by Lyapunov stability criterion. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Input-output linearization technique, Adaptive control, Lyapunov stability.
Vol. 1. n. 2, pp. 200-208
Abstract - The non-linear control scheme control based on the multiscalar machine model for a doubly fed induction generator connected to grid utility and driven by a wind turbine is presented. The input-output feedback linearisation method is applied to the dc-bus voltage regulation. And a analytical space vector modulation back-to-back PWM three-level converter is used, The paper discusses the operating principles of the power generation scheme. Simulation results show that the proposed non-linear control approach provides a decoupled control and perfect tracking of the generated active and reactive powers. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Doubly fed induction machine, wind turbine, multiscalar machine model, input-putput feedback linearization, three level converters, analytical SVMPWM algorithm.
Vol. 1. n. 2, pp. 209-216
Abstract - In these last years, there is a growing interest to use the wind turbines systems to produce the electricity (see [1]) because it uses a renewable and non polluted energy which is the wind. There is different challenges in the control of the wind energy systems and we have to take in a count a several parameters that perturb the system as: the wind speed variation, the consumption variation of the electricity energy and the kind of the power consumed (active or reactive) ...etc. In this paper, we present a method to synthesize a robust controller for a wind turbine system based in a model equipped with doubly fed asynchronous machine which is the most used model in this last years [2] and we used the H∞ robust control method with the recent method based on the use of the linear matrix inequalities (LMI’s): Gahinet-Akparian [3], the results show the stability and the performance robustness of the system in spite of the perturbations mentioned before. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Doubly fed asynchronous machine, robust control, H∞ controller design method, linear matrix inequality LMI.
Vol. 1. n. 2, pp. 217-226
Abstract -
Today, design requirements are extending more and more from electronic
(analogue and digital) to multidiscipline design. These current needs
imply implementation of methodologies to make the CAD product reliable
in order to improve time to market, study costs, reusability and
reliability of the design process. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Virtual prototyping, co-simulation, multi-domain simulation, heterogeneous systems, digital control systems, Direct Torque Control, design methodology, VHDL-AMS.
Vol. 1. n. 2, pp. 227-234
Abstract - In power electronics equipment, diode rectifies are commonly applied in the front end of DC link power converters as an interface with the grid. A rectifier is nonlinear in nature and generates harmonic currents in the AC line power, which causes a low power factor. One solution to overcome this problem is the so-called active rectifier. Additionally, this kind of device provides DC bus voltage regulation. In this paper, a passivity-based control is proposed in order to achieve DC bus regulation and power factor correction even in presence of load changes and voltage sags. Furthermore, a sliding modes observer is used to estimate AC line current to replace the current sensor, this algorithm also permits to survey the accurate operation of other (voltage) sensors in the system. Numerical simulations are performed, with severe operation settings, to validate the proposed observer-based controller. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Power quality, active rectifier, sliding modes observer, passivity-based control.
Vol. 1. n. 2, pp. 235-242
Abstract - In this paper, an optimal design of a power system stabilizer (PSS) based on multi layer perceptron (MLP) artificial neural network (ANN) using linear optimal control (LOC) method is introduced and analyzed. Benefits of the conventional power system stabilizer (CPSS), the optimizing property of LOC strategy and the quick response of ANN are combined in the proposed stabilizer. The proposed ANN-PSS is trained using data generated by the optimal control stabilizer (LOC-PSS). Using the proposed method, system damping will increase in a wide range of system operating points. Various stabilizers performances are compared and results show that designed stabilizer improves dynamic response of power system under various contingences and operating conditions. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: PSS, Liner Optimal Control, Neural Network, Training.
Vol. 1. n. 2, pp. 243-247
Abstract - The application of the genetic algorithm method (GAs) in the calculation of the optimal power flow simplifies more of the problem. In this case the mathematical aspect is based on the analogy of the physical and biological processes .this new technique or approach reduces the complexity, which is generally encountered, for the resolution of the optimization problems. The combination of the decoupled method and (GAs) method obtain a new calculation algorithm of the optimal power flow .this study present an approach to determine the optimal placement of Flexible AC Transmission System (FACTS) for voltage security enhancement, the propose method has been applied the western Algerian transmission system. The FACTS placement problem considers the upper and lower bound constraints of voltage at different load levels which minimize the system loss. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Reactive power control, algorithm genetic, FACTS devices, voltage violation.
by H. H. Afshari, H. Naseh, A. B. Novinzadeh, J. Roshanian Vol. 1. n. 2, pp. 248-257
Abstract - An optimal trajectory design of a nonlinear injection into orbit problem with maximum velocity is investigated. This design includes an exact solution to the nonlinear two-point boundary value problem which determines optimal control history as well as optimal state trajectories in the open-loop form. Also, the Neighboring Optimal Control (NOC) law is utilized for finding nonlinear optimal closed-loop solution in the exact form which can protect the mission against the environment disturbances. The NOC law can produce time-variant feedback gains minimizing the performance measure to second order for perturbations from a nominal optimal path. Generally, this law is a function of perturbations appeared in states and constraints and can be computed using the backward sweep method. The simulation results indicate that the presented methodology can be successfully utilized in the real world application with good robustness to each noise or disturbance. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Neighboring Optimal Control, Injection into Orbit, Nonlinear Explicit Guidance.
by J. Kurian, P. R. Saseendran Pillai Vol. 1. n. 2, pp. 258-262
Abstract - This paper describes the design, characterization and implementation details of a digital encoded infrared sheet of light based beacon system for intelligent control of the public transportation system. The system consists of an encoded infrared sheet of light beacon, which can convey the current location and traffic information to the vehicles. The system is capable of receiving traffic status input through a GSM (Global System Mobile) modem. The vehicles have an infrared receiver and a processor capable of decoding the information, and generating the audio and video messages to the driver. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: infrared beacons, traffic control, traffic management, driver support system, sheet of light beacons.
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