Browsing by Author "Nafa, Fares"

Now showing 1 - 8 of 8

adaptive wavelets sliding mode control for a class of second order nderactuated mechanical systems.
(2021) Nafa, Fares; Boudouda, Aimad; Smaani, Billel
The control of underactuated mechanical systems (UMS) remains an attracting field where researchers can develop their control algorithms. To this date, various linear and nonlinear control techniques using classical and intelligent methods have been published in literature. In this work, an adaptive controller using sliding mode control (SMC) and wavelets network (WN) is proposed for a class of second-order UMS with two degrees of freedom (DOF). This adaptive control strategy takes advantage of both sliding mode control and wavelet properties. In the main result, we consider the case of un-modeled dynamics of the above-mentioned UMS, and we introduce a wavelets network to design an adaptive controller based on the SMC. The update algorithms are directly extracted by using the gradient descent method and conditions are then settled to achieve the required convergence performance. The efficacy of the proposed adaptive approach is demonstrated through an application to the pendubot.
Analysis of the gate-to-channel capacitance variation for the tri-gate nanowire junctionless transistors
(2021) Smaani, Billel; Yakhelef, Yassine; Nafa, Fares; Salah, Mouhamed
In this paper, the gate-to-channel capacitance variation for the tFlat-band voltageri-gate nanowire junctionless transistor (JLT) has been analyzed. It is based on the 2-D electrostatic numerical simulation realized using Silvaco-TCAD Software. The flat-band voltage and the threshold voltage are extracted trough the plotting of the derivative for the gate-to-channel capacitance versus the gate voltage. This plotting is performed for different values of the channel width and the channel height of the tri-gate JLT. Moreover, the physical effect of the back-gate biasing has been investigated
Double-gate MOSFET model implemented in verilog-AMS language for the transient simulation and the configuration of ultra low-power analog circuits
(Polska Akademia Nauk, 2021) Smaani, Billel; Meraihi, Yassine; Nafa, Fares; Benlatreche, Mohamed Salah; Akroum, Hamza; Latreche, Saida
This paper deals with the implementation of a DC and AC double-gate MOSFET compact model in the Verilog-AMS language for the transient simulation and the configuration of ultra low-power analog circuits. The Verilog-AMS description of the proposed model is inserted in SMASH circuit simulator for the transient simulation and the configuration of the Colpitts oscillator, the common-source amplifier, and the inverter. The proposed model has the advantages of being simple and compact. It was validated using TCAD simulation results of the same transistor realized with Silvaco Software
Optimal design of wireless power transfer coils for biomedical implants using machine learning and meta-heuristic algorithms
(Springer Nature, 2024) Bennia, Fatima; Boudouda, Aimad; Nafa, Fares
The classical methods for optimizing wireless power transfer (WPT) systems using mathematical equations or finite element methods can be time-consuming and may only sometimes yield optimal designs. In order to overcome this challenge, this paper introduces a novel approach integrating machine learning techniques with meta-heuristic methods to design and optimize a miniaturized, high-efficiency WPT receiving coil for biomedical applications. The objective is to achieve dimensions below 20 mm, a depth of 30 mm within the tissue, and a frequency of 13.56 MHz. Our approach leverages a neural network (NN) model to predict efficiency based on geometric coil parameters, eliminating the need for complex equations. The NN was trained on a dataset generated via finite element method simulations. We employ two meta-heuristic algorithms, the genetic algorithm and the coyote optimization method, to find optimal parameters that maximize efficiency. Our NN model demonstrates exceptional accuracy, exceeding 97%. Furthermore, the proposed WPT coil design approach enhances transfer efficiency by up to 76%, significantly reducing computation time compared to classical methods. Finally, we validate our results using finite element simulation with Ansys Maxwell 3D.
Recent progress on field-effect transistor-based biosensors: device perspective
(Beilstein-Institut Zur Forderung der Chemischen Wissenschaften, 2024) Smaani, Billel; Nafa, Fares; Benlatrech, Mohamed Salah; Mahdi, Ismahan; Akroum, Hamza; Azizi, Mohamed walid; Harrar, Khaled; Kanungo, Sayan
Over the last few decades, field-effect transistor (FET)-based biosensors have demonstrated great potential across various industries, including medical, food, agriculture, environmental, and military sectors. These biosensors leverage the electrical properties of transistors to detect a wide range of biomolecules, such as proteins, DNA, and antibodies. This article presents a comprehensive review of advancements in the architectures of FET-based biosensors aiming to enhance device performance in terms of sensitivity, detection time, and selectivity. The review encompasses an overview of emerging FET-based biosensors and useful guidelines to reach the best device dimensions, favorable design, and realization of FET-based biosensors. Consequently, it furnishes researchers with a detailed perspective on design considerations and applications for future generations of FET-based biosensors. Finally, this article proposes intriguing avenues for further research on the topology of FET-based biosensors.
Robust decoupled adaptive fuzzy sliding mode control for a class of underactuated mechanical systems
(Levrotto and Bella, 2021) Nafa, Fares; Boudouda, Aimad; Smaani, Billel
Nowadays, Underactuated Mechanical Systems (UMS) remain an interesting research field for control laws development. This work deals with the design of an adaptive controller on the basis of Sliding Mode Control (SMC) and the universal approximation property of Fuzzy Systems (FS) for a classe of second order UMS two Degrees of Freedom (DOF). We first design an SMC law to force a coupled sliding urface to be reached in finite time. Second, by considering model uncertainties, fuzzy systems are then introduced to approximate the unknown controller. The adjustable parameters are updated by using gradient descent method. Through the stability analysis for both cases, it is shown that the system converges asymptotically to its equilbrium points in finite time. To demonstrate the validity and the performance of the proposed methods, an appropriate numerical application to an overhead crane systems is presented
Spectral analysis of switch voltage for dual randomized PWM DC-DC converters operating in DCM
(Taylor and Francis, 2021) Boudouda, Aimad; Bouzida, Ahcene; Nafa, Fares
This paper addresses the spectral characteristics of a dual randomised pulse width modulation scheme (RCFM-RPPM) for reducing conducted EMI in the basic DC-DC converters (buck, boost, and buck-boost) operating in discontinuous conduction mode (DCM). It combines two simple schemes, random carrier frequency modulation (RCFM), and a random pulse position (RPPM). First, the modulating principle of the dual randomised PWM is presented. Then, a mathematical model of power spectral density (PSD) that characterises the switch voltage of the three basic DC-DC converters is derived. The mathematical model is validated by simulation of a buck converter operating in DCM. Analytical and simulation results show the effectiveness of PSD spreading of the dual randomised scheme compare to the simple randomised schemes. Moreover, the PSD analysis is confirmed by FFT (Fast Fourier Transform) analysis of the switch voltage. Finally, the effect of randomness levels on the PSD spreading is studied
Wireless Power Transfer Optimization Using Meta-heuristic Algorithms
(IEEE, 2024) Bennia, Fatima; Boudouda, Aimad; Nafa, Fares
The importance of Wireless Power Transfer (WPT) technology in biomedical implants to mitigate the risk of regeneration has increased significantly in recent years. WPT systems are dependent on key parameters such as the coupling coefficient (K), quality factor (Q), and mutual inductance (M), which play a crucial role in determining power transfer efficiency. These parameters are closely related to the geometric characteristics of the coils involved. Therefore, this study explores various meta-heuristic algorithms to search for optimal parameters that maximize power transfer efficiency. The initial results demonstrate that these algorithms perform well across different iterations. To confirm these findings, the study conducted comprehensive validation using Ansys Maxwell software to verify the optimal values obtained through optimization.