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2016

J. Nebhen, N. Brochard, J. Dubois, D. Ginhac

Design of Low-Noise and Low-Power Photoreceptor for CMOS Vision Sensor , IEEE International Conference on Electronics, Circuits and Systems (ICECS), 11 December 2016, Monte Carlo, Monaco, France. , 2016-12-11
[Abstract]
Abstract
This paper presents the design of a low-power and low-noise CMOS photo-transduction circuit. We propose to use a pseudo-cascode split-length transistor technique for noise reduction of photoreceptor in the subthreshold by exploiting the small size effects of CMOS transistors. Several power and noise optimizations, design requirements, and performance limitations relating to the CMOS photoreceptor are presented. This new structure with split-length transistor technique ensures low noise and low power consumption. The CMOS photoreceptor, implemented in a 130 nm standard CMOS technology with a 1.2 V supply voltage, achieves a noise floor of 0.05 µV within the frequency range from 1 Hz to 10 kHz. The current consumption of the CMOS photoreceptor is 827 nA. This paper shows the need for the design of phototransduction circuit at low voltage, low noise and how these constraints are reflected in the design of CMOS vision sensor.

N. Brochard, J. Nebhen, D. Ginhac

3D-IC: New Perspectives for a Digital Pixel Sensor , 10th International Conference on Distributed Smart Cameras (ICDSC 2016), Paris, France, , 2016-09-12
[Abstract]
Abstract
This paper presents the design of a low-power low-noise CMOS photo-transduction circuit. We propose to use a pseudo-cascode split-length transistor technique for noise reduction of photoreceptor in the subthreshold by exploiting the small size effects of CMOS transistors. Several power and noise optimizations, design requirements, and performance limitations relating to the CMOS photoreceptor are presented. This new structure with split-length transistor technique ensures low noise and low power consumption. The CMOS photoreceptor, implemented in a 130 nm standard CMOS technology with a 1.2 V supply voltage, achieves a 70-dB DC gain and 40° phase margin. It achieves a noise floor of 5 within the frequency range from 1 Hz to 10 kHz. The current consumption of the CMOS photoreceptor is 827 nA. The achieved performances make it one of the best among state-of-the-art photoreceptor in terms of noise and power consumption. This paper shows the need for the design of phototransduction circuit at low voltage, low noise and how these constraints are reflected in the design of CMOS vision sensor.

N. Brochard, J. Nebhen, J. Dubois, D. Ginhac

A 1000 µm2 3D-IC Multi-Resolution Digital Pixel Sensor , SPIE Photonics Europe Conference, Brussels, Belgium , 2016-04-03
[Abstract]
Abstract
This paper presents a digital pixel sensor (DPS) integrating a sigma-delta analog-to-digital converter (ADC) at pixel level. The digital pixel includes a photodiode, a delta-sigma modulation and a digital decimation filter. It features adaptive dynamic range and multiple resolutions (up to 10-bit) with a high linearity. A specific row decoder and column decoder are also designed to permit to read a specific pixel chosen in the matrix and its neighborhood of 4 x 4. Finally, a complete design with the CMOS 130 nm 3D-IC FaStack Tezzaron technology is also described, revealing a high fill-factor of about 80%.

2015

F. Tounsi, M. Kandpal, E. Ayechi, B. Mezghani, M Masmoudi and V.R. Rao

Behavior Analysis of a 3-axis detection Push-Pull Piezoresistive MEMS Accelerometer , DOI: 10.1109/SSD.2015.7348246 , 2015-03-19
[Abstract]
Abstract
This paper reports a new concept of a 3-axis accelerometer design along with proposed fabrication steps and a circuit readout configuration. In order to achieve a better performance in terms of induced output, the study focuses on the optimization of the structure dimensions and the optimal piezoresistor's location. The proposed model will be analyzed using Finite Element Modeling (FEM) to fully investigate the stress field in the structure based on the seismic mass movement and dimensions of attachment arms. Using Finite Element Analysis results, the push–pull operation mode has been confirmed. Maximum stress magnitude with an appropriate profile has been studied in terms of various key geometric parameters. Under an acceleration of 100g, symmetric stress magnitude profile with an approximate value of 3MPa, has been detected. This paper also discusses the structure of the built-in network of the piezoresistive Wheatstone bridge circuit and its position. We also show a flip-chip process flow for the ongoing fabrication of a polymer based accelerometer prototype.

2014

J. Nebhen, E. Savary, W. Rahajandraibe, C. Dufaza, S. Meillère, E. Kussener, H. Barthélemy

Low-Noise CMOS amplifier for readout electronic of resistive NEMS audio sensor , IEEE Design, Test, Integration & Packaging of MEMS/MOEMS, Cannes Cote d’Azur, France , 2014-04-01
[Abstract]
Abstract
Investigation of readout electronic dedicated to electromechanical audio sensor is presented. The circuit is able of reading piezoresistive gauge implemented with silicon nanowire (NEMS) and bring electromechanical signal to high-resolution digital output. Low-noise low-power CMOS operational transconductance amplifier (OTA) is presented. The low-noise amplifier (LNA) has been designed in a 0.28 ?m CMOS process with a 2.5 V supply voltage and occupies an area of 120 x 160 ?m2. For the Post-layout Simulation, the OTA achieves a 65 dB DC gain. It achieves a noise floor of 6 nV/?Hz within the frequency range from 1 Hz to 10 kHz. The total power consumption including the common mode feedback circuit (CMFB) and the biasing circuit is 150 ?W.

2013

F. Haddad, W. Rahajandraibe, H. Aziza, K. Castellani-Coulié, J-M. Portal, J. Nebhen and H. Barthélemy

Low-Cost Auto-Calibration of Passive Polyphase Filter In Image Reject Receiver , IEEE International Conference on Electronics, Circuits, and Systems (ICECS), Abu Dhabi, UAE , 2013-12-08
[Abstract]
Abstract
A low-cost auto-calibration technique of Radio- Frequency (RF) Passive Polyphase Filter (PPF) for high image rejection in low Intermediate Frequency receiver is presented. The resistance values of the filter are process and temperature dependent with great mismatch constraints especially in the RF domain. That can severely impact the circuit performances if not controlled. In order to overcome this limitation, an in-line auto-calibration of the PPF resistance values, based on Design Of Experiment (DOE) methodology, is presented. Using DOE, a model is derived from thermal and process deviations of the chip responses. This approach results in a robust and low-cost solution.

J. Nebhen, E. Savary, W. Rahajandraibe, C. Dufaza, S. Meillère, E. Kussener, H. Barthélemy

Low-Noise Smart Sensor Based On Silicon Nanowires For MEMS Resistive Microphone , IEEE Sensors, Baltimore, Maryland, USA , 2013-11-03
[Abstract]
Abstract
The design of CMOS integrated circuits dedicated to hybrid integration of a MEMS resistive microphone with readout interface is presented. Audio sensing is achieved with an innovative low-cost technology that implements piezoresistive detection in MEMS devices with single crystal silicon nanowires. The complete circuit includes a custom designed analog frontend consisting of a sensor conditioning and a fourth order single bit continuous-time sigma-delta modulator (CT-??M). The complete interface circuit exhibits a current consumption of 2mA. The obtained smart-sensor features a reduced output data rate that is suitable for a wireless sensor network with direct transmission of the raw data to a remote base station.

B. Mezghani, F. Tounsi and M. Masmoudi

Sensitivity Modeling of dual-axis CMOS MEMS Convective Accelerometers using FEM and Spherical Model , Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS, April 2013, Barcelona, Spain (DTIP 2013). , 2013-04-19
[Abstract]
Abstract
This paper presents sensitivity behavior study and optimization of dual axis CMOS MEMS convective accelerometers using both analytical and FEM techniques. In a first part, newly developed accelerometer 3D model is used in FEM simulations. Using different sizes for micromachined and square cover shapes, it is found that sensitivity readings and its maximum position in cavity are affected by both cover size and shape. In addition, micromachined bottom cavity, with half width of 300µm, is found to produce sensitivity saturation starting at a depth of 200µ for both cover shapes. The used cover size is that offering maximum sensitivity readings. From computed heating efficiency values, it is concluded that dual axis accelerometers are more power efficient than single axis ones. In the second part, we present Hardee’s spherical model and investigate its possible application on the dual axis accelerometer. It is concluded that inner and outer isotherms deformation should be modeled by including sensor geometry parameters in governing equations.

B. Mezghani, F. Tounsi, and M. Masmoudi

Dual-axis CMOS MEMS Convective Accelero-meters sensitivity modeling using FEM and spherical model , 15th Conference in Design, Test, Integration & Packaging of MEMS/MOEMS, DTIP'13, 16-18 April, 2013, Barcelona, Spain. , 2013-04-16
[Abstract]
Abstract

E. Savary, J. Nebhen, W. Rahajandraibe, C. Dufaza, S. Meillère, E. Kussener, H. Barthélemy

Readout Electronic for Digital Output Resistive NEMS Audio Sensor , 8th IEEE International conference on Design & Technology of Integrated Systems in nanoscale era, DTIS , 2013-03-26
[Abstract]
Abstract
Investigation of readout electronic dedicated to electromechanical audio sensor is presented. The circuit is able of reading piezoresistive gauge implemented with silicon nanowire (NEMS) and bring electromechanical signal to highresolution digital output.

B. Mezghani, F. Tounsi, H. Yaich and M. Masmoudi

Conductive Behavior Modeling of Dual-axis CMOS MEMS Convective Accelerometers Using 3D FEM and Spherical Model , International Multi-Conference on Systems, Signals & Devices, March 2013, Hammamet, Tunisia (IEEE – SSD 2013). , 2013-03-22
[Abstract]
Abstract
This paper presents heat conduction modeling of dual axis micromachined convective accelerometers. Results from FEM simulation are used to develop an analytical model of heat conduction main parameters. Two variables are used in FEM simulations: heater temperature and cavity depth. The latter parameter has a large impact on the overall conductive behavior of thermal accelerometers since it fixes the volume where the heat bubble can expand. Simulation results are used in a derived spherical model to develop an analytical expression of outer isotherm equivalent radius. The hot bubble radius and form are closely related to sensor geometry parameters and temperature. Two distinct equivalent radius modeling are studied and are used to express both heater heat transfer coefficient and common mode. These physically-based derived expressions govern the overall sensor conductive behavior. It is also shown that these derived expressions are still valid for different sensor design geometries.

2012

J. Nebhen, S. Meillere, J-L. Seguin, K. Aguir, M. Masmoudi, H. Barthelemy

A Temperature Compensated CMOS Ring Oscillator For Wireless Sensing Applications , 10th IEEE International NEWCAS Conference, NEWCAS, Montréal, Canada , 2012-06-17
[Abstract]
Abstract
This paper presents a CMOS voltage controlled ring oscillator (VCO) with temperature compensation circuit suitable for low-cost and low-power wireless sensing applications. To operate at low frequency, a control voltage generated by a CMOS bandgap reference (BGR) is described and the measurement results of the fabricated chips are presented. The output voltage of the reference is set by resistive subdivision. In order to achieve small area and low power consumption, n-well resistors are used. This design features a reference voltage of 1V. The chip is fabricated in AMS 0.35 ?m CMOS process with an area of 0.032mm2. Operating at 1.25V, the output frequency is within 200±l0kHz over the temperature range of -25°C to 80°C with power consumption of 810?W.

J. Nebhen, S. Meillere, J-L. Seguin, K. Aguir, M. Masmoudi, H. Barthelemy

A temperature Compensated CMOS Ring Oscillator For Chopper Amplifier MEMS Gas Sensor , 8th Conference on Ph.D. Research in Microelectronics & Electronics, PRIME, Aachen, Germany , 2012-06-12
[Abstract]
Abstract
This paper presents a CMOS voltage controlled ring oscillator (VCO) with temperature compensation circuit suitable for low-cost and low-power MEMS gas sensor. This compensated ring oscillator is dedicated to Chopper Stabilized CMOS Amplifier (CHS-A). To operate at low frequency, a control voltage generated by a CMOS bandgap reference (BGR) is described and the measurement results of the fabricated chips are presented. The output voltage of the reference is set by resistive subdivision. In order to achieve small area and low power consumption, n-well resistors are used. This design features a reference voltage of 1V. The chip is fabricated in AMS 0.35 ?m CMOS process with an area of 0.032mm2. Operating at 1.25V, the output frequency is within 200±l0kHz over the temperature range of -25°C to 80°C with power consumption of 810?W.

J. Nebhen, S. Meillere, J-L. Seguin, K. Aguir, M. Masmoudi, H. Barthelemy

A 250 ?W 0.194 nV/rtHz Chopper-Stabilized Instrumentation Amplifier for MEMS Gas Sensor , 7th IEEE International conference on Design & Technology of Integrated Systems in nanoscale era, DTIS, Gammarth, Tunisia , 2012-05-16
[Abstract]
Abstract
In this paper, a low-noise, low-power and low voltage Chopper Stabilized CMOS Amplifier (CHS-A) is presented and simulated using transistor model parameters of the AMS 0.35 ?m CMOS process. Chopping is used to modulate the offset away from the output signal where it can be easily filtered out, providing continuous offset reduction which is insensitive to drift. The CHS was simulated using typical transistor model parameters BSIM 3V3 of the 0.35 ?m CMOS process technology from AMS [1]. Under at ±1.25 V power supply and a voltage gain of 49dB, the total power consumption is 250 ?W only. At the same simulation condition, it achieves a noise floor of 0.194 nV / Hz within the frequency range from 1 kHz to 10 kHz and the inband PSRR is above 90, the CMRR exceeds 120 dB. The circuit occupies an effective small chip area of 3.233 mm2.

B. Mezghani, F. Tounsi, A.A. Rekik, F. Mailly, M. Masmoudi and P. Nouet

Efficiency modeling of a CMOS MEMS convective accelerometer , International Conference on Design and Technology of Integrated Systems in Nanoscale era, May 2012, Guammarth, Tunisia, (IEEE – DTIS 2012). , 2012-03-23
[Abstract]
Abstract
This paper reports efficiency modeling using 3D FEM simulation of a convective accelerometer obtained by FSBM of a die fabricated using standard CMOS technology. In such sensors, best sensitivity is obtained by placing temperature detectors where air temperature is the most sensitive to acceleration. This will obviously depends on 3D effects. In a previous work, a behavioral model of the sensor including only 2D effects was developed. This work investigates 3D effects which give the opportunity to better predict not only sensor sensitivity but also power dissipation. Experimental sensitivity values and 3D FEM ones are verified for two different sensors and two different heater temperatures. For a prototype having a heater-cavity border distance of 340µm and a heater length of 230µm, maximum sensitivity point is obtained for detectors localized at a distance of 125µm from heater center. Using this 3D geometry in FEM simulations, we show that electrical power decreases more rapidly than sensitivity when heater length is reduced. Moreover, when detectors are shortened, the sensitivity will be quite higher with an optimal value obtained for a detector implemented on one third of the side bridge.

2011

B. Mezghani, A. Brahim, F. Tounsi, A.A. Rekik, M. Masmoudi and P. Nouet

From 2D to 3D FEM simulations of a CMOS MEMS convective accelerometer , International Conference on Microelectronics, December 2011, Hammamet, Tunisia (IEEE – ICM 2011). , 2011-12-23
[Abstract]
Abstract
In this paper, we present 3D FEM simulations of a CMOS MEMS convective accelerometer. Differences between 3D and previously published 2D simulations are also discussed. We describe sensor architecture and we present a sensor model that is used for 3D FEM simulations. The prototype has a heater-cavity border distance of 350µm. We show the details of the sensitivity evaluation along the sensitive axis. It is found that the maximum sensitivity location is at a distance of 125µm from the heater center. So, the detector should be placed closer to the heater than the mid distance. It is shown that this is closely related to the smaller size of isotherms obtained in 3D simulations.

J. Nebhen, S. Meillere, J-L. Seguin, K. Aguir, M. Masmoudi, H. Barthelemy

Low Noise Micro-Power Chopper Amplifier for MEMS Gas Sensor , 18th IEEE International Conference Mixed Design of Integrated Circuits and Systems, Poland , 2011-06-16
[Abstract]
Abstract
We describe in this paper a low-noise, low-power and low-voltage analog front-end amplifier dedicated to high resistive gas sensor detection. A mobile sensor system for very low level signals such as gas spikes detection is required to implement with a scaled CMOS technology. For a key circuit of these systems, a Chopper Stabilization Amplifier (CHS) which suppresses DC offset and 1/f noise figure of MOS devices is commonly used. This CHS operates from a modest supply voltage of ±1.25 V, drawing 4 ?A of current thus consuming 5 ?W of power. The resulting equivalent input referred noise is 0.19 nV / Hz for a chopping frequency of 210 kHz.

J. Nebhen, S. Meillere, J-L. Seguin, K. Aguir, M. Masmoudi

Low Noise CMOS Chopper Amplifier for MEMS Gas Sensor , IEEE International Conference on Autonomous and Intelligent Systems AIS, Burnaby, BC, Canada , 2011-06-10
[Abstract]
Abstract
We describe in this paper a low-noise, low-power and low-voltage analog front-end amplifier dedicated to high resistive gas sensor detection. A mobile sensor system for very low level signals such as gas spikes detection is required to implement with a scaled CMOS technology. For a key circuit of these systems, a Chopper Stabilization Amplifier (CHS) which suppresses DC offset and 1/f noise figure of MOS devices is commonly used. This CHS operates from a modest supply voltage of ±1.25 V, drawing 4 ?A of current thus consuming 5 ?W of power. The resulting equivalent input referred noise is 0.19 nV / Hz for a chopping frequency of 210 kHz.

2007

B. Mezghani, F. Tounsi and M. Masmoudi

Mechanical-Thermal Noise Characterization of a new Micromachined Acoustic Sensor , In Proceedings of SPIE Fluctuations and Noise, Noise and Fluctuations in Circuits, devices and Materials, Vol. 6600, 660015, Florence, Italy (SPIE – FN 2007). , 2007-04-06
[Abstract]
Abstract
A new integrated CMOS micromachined inductive microphone is studied and characterized for mechanical-thermal noise. This acoustic sensor has one suspended membrane attached to the substrate with 4 arms, the I-beam or L-beam shaped attachments. This membrane has 1.4x1.4mm2 active area, 22µg mass and its natural frequency is found to be around 250 kHz, for the I-beam and 134 kHz, for the L-beam attachment. We give a brief explanation of the superiority of this new design over conventional acoustic sensors. Then, some experimental points are discussed and solutions are given. This sensor is analyzed for mechanical-thermal noise by applying a new developed analysis based on mass and natural frequency. Our system damping factor is found to be 5x10-2 N.s.m-1, which gives a fluctuating force spectral density of 2.88x10-11 N.Hz-1/2. This corresponds to an A-weighted sound level of about 39 dB(A) SPL. A SNR value of 55 dB is found for an incident pressure of 1 Pa on the suspended membrane. The relationship between the SNR and the mechanical and geometrical characteristics of the suspended membrane is also investigated. Finally, our sensor mechanical noise displacement is evaluated, around 10-15 m.Hz-1/2, and plotted for the two attachment types.

B. Mezghani, F. Tounsi, S. Smaoui and M. Masmoudi

Mechanical Noise Modeling of a new Micromachined Acoustic Sensor , CD-ROM International Multi-Conference on Systems, Signals & Devices, March 19-22, Tunisia (IEEE – SSD 2007). , 2007-03-23
[Abstract]
Abstract
In this paper, we present mechanical-thermal noise calculation and modeling for a new CMOS micromachined acoustic sensor. This new inductive microphone has a suspended moving membrane attached to the substrate with 4 attachment arms. Two different attachment structures are studied. The membrane has a 1.4x1.4mm2 surface and a total mass of 22.4 µg. The natural frequency of the suspended membrane is found for the two different attachment structures, the I-shaped and the L-shaped beams. Using a theoretical mechanical modeling, we get natural frequency values of 263 kHz and 115 kHz, for the I-shaped and L-shaped beam design, respectively. With a numerical FEM analysis, we get natural frequency values of 238 kHz and 154 kHz. Average natural frequency values of 250 kHz and 134 kHz are used. Thermal noise contribution of the two different attachment types is investigated. In addition, damping factor and noise level are evaluated for different membrane mass values. It is found that the thermal noise contribution is about the same for the I-shaped and L-shaped beam designs. The same conclusion is drawn when the mass of the membrane is changed.

2006

Mezghani B., Haboura K., Tounsi F., Smaoui S., El-Borgi S., Choura S. and Masmoudi M.

Theoretical and Numerical modeling of a CMOS micromachined acoustic sensor , In Proceedings of International Conference on Design and Test of Integrated Systems in Nanoscale Technology, September 5-7, Tunisia, 441-444 (IEEE – DTIS 2006). , 2006-09-07
[Abstract]
Abstract
In this paper, we present theoretical and numerical modeling done on a new structure of CMOS micromachined inductive microphone. Its mode of operation is based on the variation of the mutual inductance between an external fixed inductor and an internal suspended inductor. This internal inductor is designed on a 1.4x1.4mm2 suspended membrane. The displacement of the suspended membrane with two different attachment structures, the I-shaped and the L-shaped beams, is studied. Using a theoretical mechanical modeling, we get displacement values of 13.11µm and 68.82 µm, for the I-shaped and L-shaped beam design, respectively. With a numerical FEM analysis, using the Ansys software, displacement values of 12.7µm and 63.5 µm were found for the I-shaped and L-shaped beam design, respectively. Using the analogy between acoustic, mechanical and electrical domains, the dynamic behavior of the L-shaped beam design sensor is studied and a corner frequency around 200 kHz is found. This value is also found when applying analytical dynamics principles to determine the equations of motion for the suspended membrane. A FEM analysis, using the Ansys software, is conducted in order to validate this theoretical model.

0

Hanene Rouabah, Chokri Abdelmoula, Mohamed Masmoudi

Behavior Control of a Mobile Robot Based on Fuzzy Logic and Neuro Fuzzy Approaches for Monitoring Wall , 2012 International Conference on Design & Technology of Integrated Systems in Nanoscale Era , 0000-00-00
[Abstract]
Abstract
Abstract— This work describes the design and development of controllers based on artificial intelligence tried on a newly design of a mobile robot type-vehicle to control behavior for monitoring wall. Two approaches have been optimized and developed to control the robot: The first one is based on Fuzzy logic. This control algorithm combines the different sensory information and provides a suitable control command allowing the mobile robot to follow the wall deviations. The second approach consists of applying a hybrid-type Neuro-Fuzzy ANFIS controller for the same task. This controller combines the advantages of Fuzzy logic and Neural Networks. Simulations results are presented and implemented with VHDL using ANFIS architecture. Keywords- Mobile Robot; Wall Following; Fuzzy Logic; Neural Networks; Neuro-Fuzzy; ANFIS

Hanene Rouabah,Chokri Abdelmoula,Mohamed Masmoudi

The Realization of a Neural Network Controller for Vehicle-Type Mobile Robot Navigation , 2012 International Conference on Design & Technology of Integrated Systems in Nanoscale Era , 0000-00-00
[Abstract]
Abstract
Abstract— This work is part of improving the autonomous navigation of mobile robots. In an environment where many obstacles in form of wall are present, the robot must detect obstacles around it, steer to the nearest and track its deviations keeping a desired distance fixed. A joint use of information issued from the three sensors installed on the platform: in front, on the left and on the right are used to determine the proper motion for the robot at each position allowing it to navigate autonomously. The effectiveness of Neural Networks in mobile robot control is important in their learning abilities and their capacity to treat noisy data. Keywords-Mobile Robot; Wall Following; Neural Networks

Chokri ABDELMOULA Fakher Chaari Mohamed MASMOUDI

Implementation of Applications on a Newly Designed Robot Prototype: “Autonomous Navigation and Parallel Parking” , 2009 International Conference on Signals, Circuits and Systems , 0000-00-00
[Abstract]
Abstract
Abstract— Autonomous navigation and parallel parking of robots is usually a challenging maneuver for conductors in industrial environments and in heavy traffic congestion respectively. Soft computing techniques are suited for robots like car control system when modeled by highly non linear differential equations and navigation in unknown and unstructured environments. To demonstrate their applicability in real-world applications, two easy control units are designed for performing tasks. In this paper, a novel vision of autonavigation system and parallel parking is proposed and confirmed on the newly designed robot prototype for each model. The experimental results show the accuracy of measurement and recognition, and the robustness of dynamic auto-navigation in indoor environments. All these applications are implemented on the new prototype of the robot designed in the (EMC) research unit at the National Engineering School of Sfax. Keywords— Auto-navigation, 3D measurement, mobile robot, intelligent parking system.

Chokri ABDELMOULA, Mohamed MASMOUDI, Fakher CHAARI

Obstacle Avoidance of a Mobile Robot Using a Hierarchical Control , 2008 International Conference on Design & Technology of Integrated Systems in Nanoscale Era , 0000-00-00
[Abstract]
Abstract
Abstract— A new approach of obstacle avoidance of a mobile robot (autonomous vehicles) using a hierarchical control for navigation is proposed. It is based on the identification of the kinematics model of the mobile robot to determine the procedure of navigation in an unknown environment. Then, the information about the global goal and the long-range sensory data, with regards to the navigation environment, are used to guide the mobile robot to reach its sub-goal while avoiding collisions. The implementation results of this concept are presented confirming the effectiveness of the proposed control approach. Keywords: Autonomous navigation, Mobile robot, Hierarchical control, Unknown Environment

Chokri ABDELMOULA Fakher Chaari Mohamed MASMOUDI

A New Generation of a Mobile Robot For Universal and Didactic Applications , 2009 6th International Multi-Conference on Systems, Signals and Devices , 0000-00-00
[Abstract]
Abstract
Abstract – In this paper, a novel prototype of a wellstructured robot for navigation in an industrial environment, and for didactic applications is presented. The robot has two axels. The driving wheels are mounted in the rear axle of the robot, and the front axle which is equipped by two wheels is responsible of the rotation and maneuvering the robot. In addition to the mechanical components, the prototype is equipped with a DC power supply, three infra-red sensors, one ultrasound sensor, and control modules composed of an FPGA card, a microcontroller card and two cards for commanding the two DC motors installed in the rear axle, and the stepper motor which is installed in the front axle. These two cards are used to control those actuators. The parameters of the mechanical and electronic components are optimized to perform multiple tasks for training and instruction applications. A mathematical model that describes the dynamics of the robot prototype is also developed. Simulation, experimental and theoretical investigations were carried out consisting in avoiding navigation with specific maneuvers and for didactic applications such us self parking in complex environments. Experimental and theoretical results agree well in both applications. Keywords: Autonomous vehicles, embedded design, mobile robot

Amel Neifar, Hatem Trabelsi, Ghazi Bouzid and Mohamed Masmoudi

Design of a zero crossing BFSK demodulator for a wireless sensor , 2012 International Conference on Design & Technology of Integrated Systems in Nanoscale Era , 0000-00-00
[Abstract] [Full Text]
Abstract
In this paper, a transistor-level simulation result of a Zero crossing BFSK demodulator is presented. The detector will be integrated into a frequency-hopped spread spectrum receiver operating in the 863-870 MHz ISM band, using the zigbee protocol (IEEE 802.15.4). This end to demodulate a received bit sequence with a bit rate equal to 20 kbps using 0.35 m CMOS technology and a 3V power supply. The proposed demodulator dedicated to an application of low power and low cost can maintain good performance under process variation. The BER results show that the proposed demodulator needs only 10.9dB input signal_to_noise ratio to achieve a BER of 10-3 as specified in zigbee standard.

Amel Neifar, Ghazi Bouzid, Hatem Trabelsi and Mohamed Masmoudi

Design of Ultra Wideband Oscillator in 0.18 ?m Standard CMOS Technology , 1st International Conference on Advanced Technologies for Signal and Image Processing - ATSIP'2014 March 17-19, 2014, Sousse, Tunisia , 0000-00-00
[Abstract] [Full Text]
Abstract
This paper describes the design of a 3-5 GHz oscillator for Impulse-Radio Ultra-Wideband (IR-UWB) transceiver in the 0.18?m CMOS technology. The most important specifications for the voltage control oscillator (VCO) are provided and architecture for an existing frequency plan is introduced along with a discussion on its performance and implementation. The simulated VCO can achieve very wide tuning range along with low phase noise performance that varies from -92.02dBc/?Hz to -73dBc/Hz at 1 MHz frequency offset from the carrier and the overall power consumption is 18.1 mW from a 1.8V voltage supply.