Samir Ladaci

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This paper presents a new approach to robust adaptive control, using fractional order systems as parallel feedforward in the adaptation loop. The problem is that adaptive control systems may diverge when confronted with finite sensor and actuator dynamics, or with parasitic disturbances. One of the classical robust adaptive control solutions to these(More)
This paper investigates the L-stability properties of fractional nonlinear differential equations. Systems defined on a finite time interval are considered. The principal contributions are summarized in a theorem which give sufficient conditions for bounded stability of fractional order systems. We show that the proposed results can not be extended to the(More)
In this paper, we propose a new control scheme based on Extremum-Seeking (ES) combined with Fractional-Order Systems (FOS). This auto-tuning strategy involving a fractional order integral action, is developed to optimize the system response without external dithering, exploiting disturbances already present in the control system. We show by mean of(More)
This paper investigates the linear feedback control of the fractional-order Chen chaotic system. The analysis and implementation of the control system in the frequency domain is realized by mean of Charef's singularity function method. A numerical simulation shows the effectiveness of the proposed controller in stabilizing the system on an unstable fixed(More)
Based on the bifurcation diagram technique, this paper analyses the stabilization conditions of the nonlinear chaotic Genesio-Tesi system with the use of a fractional order control scheme. Stability analysis is performed for the closedloop nonlinear chaotic system behavior, for the fractional order integral and derivative actions by mean of the bifurcation(More)
A fuzzy adaptive controller scheme is presented in this work, where the system dynamics are estimated in real time by mean of fuzzy systems. The controller design is dedicated to a class of nonlinear SISO systems with unknown model and control gain sign. Such a control design becomes a true challenge, and generally impossible via the inversion if the system(More)
The main objective of this work is to study design methods of polynomial control laws by pole placement that presents actually smart solutions to many industrial applications. Even if these regulators are widely used, most of their applications concern problems where the reference signal does not vary in time. In this paper, we propose an indirect adaptive(More)
Fractional order adaptive controllers are gathering a great interest in the control research community mainly because of the additional tools and freedom offered to the designer in order to respond to more severe control specifications, for processes under control in real-time. The present work introduce a new innovation for a particular regulator in this(More)