Assistant Professor in Control Engineering, (Maître de Conférence, classe "A") ----------------------------------------------------------- "20 August 1955" Uninersity of Skikda, Faculty of Technology, Department of Electrical Engineering, BP 26, Skikda 21000, Algeria. http://www.univ-skikda.dz Tel/Fax: 00213 (0) 38 70 17 00 ----------------------------------------------------------- Laboratory of Signal Processing, University of Mentouri, Department of Electronics, Route de Ain Elbey, 25000 Constantine, Algeria. http://www.umc.edu.dz Tel/Fax : 00213 (0) 31 81 89 85
samir_ladaci@yahoo.fr
Samir Ladaci received the State Engineer degree in Automatics from the Polytechnic School of Algiers in 1995 and the Magister degree in Industrial Automation from Annaba University, Algeria in 1999. He received his Ph.D. and HDR degree (Habilitation à diriger les Recherches) from the department of Electronics, Mentouri University of Constantine, Algeria in 2007 and 2009 respectively. Since 2001, he is an assistant professor in the Department of Electrical Engineering at Skikda University, Algeria. From 2002 to 2010, he made many research sojourns in IRCCyN laboratory (Nantes, France). His current research interests include Fractional order Control, Adaptive Control, Robust Control.
Abstract: In this paper we have introduced as a model in the adaptive Internal Model Control (IMC) structure a fractional order system
to obtain a fractional adaptive IMC scheme. We have shown that this adaptive control scheme always provides theoretical
guarantees of stability when a stable fractional order transfer function is used as an IMC parameter and that the use of
this fractional IMC parameter can improve the performances of the control system along with its robustness against noises.
A comparative simulation example is given to illustrate the efficiency of the proposed fractional order adaptive control
scheme. Copyright q 2010 John Wiley & Sons, Ltd.
Abstract: In this paper we show that a fractional adaptive controller based on high gain output feedback can always be found to stabilize any given linear, time-invariant, minimum phase, siso systems of relative degree one. We generalize the stability theorem of integer order controllers to the fractional order case, and we introduce a new tuning parameter for the performance behaviour of the controlled plant. A simulation example is given to illustrate the effectiveness of the proposed algorithm.
Abstract: Introducing fractional operators in the adaptive control loop, and especially in Model Reference Adaptive Control (MRAC), has proven to be a good mean for improving the plant dynamics with respect to response time and disturbance rejection. The idea of introducing fractional operators in adaptation algorithms is very recent and needs to be more established, that is why many research teams are working on the subject. Previously, some authors have introduced a fractional model reference in the adaptation scheme, and then fractional integration has been used to deal directly with the control rule. Our original contribution in this paper is the use of a fractional derivative feedback of the plant output, showing that this scheme is equivalent to the fractional integration, one with a certain benefit action on the system dynamical behaviour and a good robustness effect. Numerical simulations are presented to show the effectiveness of the proposed fractional adaptive schemes.
Abstract: In recent years, it is remarkable to see the increasing number of studies related to the theory and application of fractional order controller (FOC), especially PIλDμ. Many new ideas have been proposed in specialized literature, based on classical PI-type adaptive controller.
In this paper a fractional adaptive PIλ controller for a buck DC/DC converter operating in the continuous conduction mode will be proposed. The controller is designed to monitor the output loading condition, and adaptively changes its control parameters to give optimal dynamic performances corresponding to any loading variations. Introducing fractional order operators in the control scheme has proven to give results which can either be better than or at least similar to the integer one.
Simulation results show that the DC-CD Buck converter is stabilized with the fractional adaptive PIλ Controller and gives more flexibility to improve the output behavior when compared to the classical control scheme. In fact we obtain a faster transient response and reduced steady state error and improved controller's reliability during under loaded operation.
Further research work will concern the robustness analysis of the proposed controller in practical working conditions of the DC-CD Buck converter.
Abstract: Over the few last years the idea of introducing fractional calculus
and systems in adaptive control has found a great interest, for the benefit one
can win in the performances given by such systems. In adaptive control, the dynamic
behavior of the system is defined by a chosen reference model and an
adaptation algorithm modifies the correction to minimize the process output
error. In this work, an adaptive control with a fractional order reference model
is suggested. The main idea consists of making beforehand an approximation
of the fractional reference model using one of the frequency domain approximation
methods. After that, we use a classical algorithm of the adaptive control
with the resulting reference model. Our objective is to find a control which
takes the system to the desired state (the referential signal) with an improved
behavior when compared to the integer order model scheme. The results of simulation
have confirmed the efficiency proposed fractional order reference
model adaptive controller.
Abstract: Recently, a great number of researchers have focused on fractional order systems (FOS). Many new ideas have
been proposed for analysis and design of fractional order controllers (FOC). Based on classical PI-type adaptive
controller for a given class of linear systems with relative degree one and constant disturbances, a concept of adaptive fractional PI controllers, involving a fractional order integral action of order lambda, is proposed in this paper. The mager contribution of this work is to derive the stability proof of the proposed fractional control scheme. An Illustrative example is presented to show the use of the derived formulas and the advantages of the proposed adaptive fractional PIl controller compared to the adaptive PI-type controller.
Abstract: In this paper we demonstrate that a fractional adaptive controller based on the high gain output feedback stabilizes the class of linear, time-invariant, minimum phase, siso systems of relative degree one. We generalize the stability theorem of integer controllers to fractional order controllers whose derivative order is a real number between one and two, and introduce a new tuning parameter for the performance behaviour of the controlled plant. A simulation example is given to illustrate the effectiveness of the proposed algorithm.
