clovis francis | Universite Libanaise (original) (raw)

Papers by clovis francis

2018 7th European Workshop on Visual Information Processing (EUVIP), 2018

In this work, we evaluate different classification algorithms used for multi-target detection in ... more In this work, we evaluate different classification algorithms used for multi-target detection in hyperspectral imaging. We took into consideration the scenario of landmine detection in which we compared the performance of each method in various cases. In addition, we introduced the detection of targets using artificial intelligence-based methods in order to obtain better detection performance together with target identification and estimation of its abundance. These algorithms were tested on various types of hyperspectral images where the spectra of the landmines were planted in different proportions in the hyperspectral scenes. The results show the advantage of using our training strategy for radial basis function neural networks (RBFNN) in order to detect, identify and estimate the abundance of the targets in hyperspectral images at the same time. Moreover, the proposed technique requires a comparable computational cost with respect to state of art target detection techniques.

Nasa Sti Recon Technical Report N, Aug 1, 1985

Abstract : A broadband cable system was installed at U.S. Army Combat Systems Test Activity (USAC... more Abstract : A broadband cable system was installed at U.S. Army Combat Systems Test Activity (USACSTA) in 1980 to allow data communication between test site data acquisition systems. The high-speed modems selected for this function were found to be unreliable and unmaintainable. This project was to investigate alternative equipment which would be suitable for providing high-speed data communications on the USACSTA broadband cable system. The investigation was conducted at USACSTA from May 1983 to August 1985. It is concluded that (1) The Fairchild Data Corporation M505 provides the flexibility, reliability, and maintainability required for the USACSTA broadband network; (2) The best network topology consists of using a computer at Building 436 to perform network routing and not using a translator; (3) Routine preventive maintenance must be performed on the broadband cable system to maintain its effectiveness; (4) The CATEL DM-2100 provides adequate low-speed peformance; (5) Additional cable drops must be provided to meet user needs; (6) An improved software data transfer utility must be created to support the broadband cable system requirements; (7) The addition of an audio-communications capability to the broadband cable system would increase its utility and improve range communications. (Author)

Abstract : At the present time automotive test data relative to use and operational environment i... more Abstract : At the present time automotive test data relative to use and operational environment is gathered by tachographs, analog tape recorders, and pulse code modulation (PCM) encoders. This project was to develop a Vehicle Performance Recorder (VPR) to augment the existing automotive test capability. The design objectives of the VPR were: self-contained, analog and digital inputs, digital recording, programmable, not require an on site or skilled operator, 8-hour capacity, 0.1% analog accuracy, 30-second time resolution, useable in US Army Aberdeen Proving Ground (APG) environment, 28 VDC operation, and internal battery operation. A unit which meets these objectives is described in detail. The VPR uses a commercial cassette recorder and a custom controller to provide a flexible, low-power consumption data acquisition system. A description of alternative systems is also provided. It is concluded that: (a) the VPR satisfies a wide variety of measurement needs; (b) commercially manufactured units now exist with a wide spectrum of capabilities; (c) the Army developed Vehicle Monitoring System (VMS) may be available in the future; (d) no single unit satisfies all possible data acquisition requirements. It is recommended that a commercially available unit be used if possible; if not then the VPR be used. (Author)

Journal of Applied Physics, 1995

2022 International Conference on Unmanned Aircraft Systems (ICUAS)

IEEE Transactions on Vehicular Technology

2019 IEEE Intelligent Vehicles Symposium (IV), 2019

In this paper, we focused on the yaw motion dynamics for light electric vehicles. The objective i... more In this paper, we focused on the yaw motion dynamics for light electric vehicles. The objective is to track the yaw rate reference in order to enhance lateral stability. Two controllers were designed, a simple PID controller and a third generation CRONE controller. The design methodology considers the total mass of the vehicle, the longitudinal speed, and the road adhesion as uncertain parameters. Later, we analyze the effect of vertical dynamics, on a controlled full vehicle system, where the variation of the normal wheel-contact forces was taken into consideration. A double lane change maneuver is simulated, and the results show the robustness of the CRONE controller against the uncertain parameters and its effectiveness to lessens the influence of load transfer variations.

2019 4th Conference on Control and Fault Tolerant Systems (SysTol), 2019

This paper considers a distributed planner method for multiple unmanned aerial vehicles (UAV), ba... more This paper considers a distributed planner method for multiple unmanned aerial vehicles (UAV), based on a leaderless approach, using an Artificial Bee Colony (ABC) optimization algorithm. The ABC algorithm is a metaheuristic optimization method inspired by the intelligent behavior of the honeybee swarm. The proposed ABC, implemented on each UAV independently, is used to compute velocity profiles that avoid obstacles and collisions between the UAVs while ensuring the fleet formation control and the target tracking. The proposed algorithm is demonstrated by simulations on Matlab/Simulink in different scenarios.

IFAC-PapersOnLine, 2018

In this paper, the standard PID controller and the fractional first generation CRONE controller a... more In this paper, the standard PID controller and the fractional first generation CRONE controller are applied on the anti-roll moment system to improve ride comfort for passengers in the frame of global chassis control of electric vehicles. A comparative study is done showing the performance and the robustness of the two controllers, in frequency and time domain. It is shown that the first generation CRONE control-system is able to provide robust fractional order controller for uncertain perturbed plants.

IFAC-PapersOnLine, 2019

Active suspensions are an object of interest nowadays, they have been a topic of research for dec... more Active suspensions are an object of interest nowadays, they have been a topic of research for decades due to their key role in Global Chassis Control (GCC). Indeed, a wellcontrolled active suspension system may considerably improve not only the passenger comfort by compensating the chassis dynamics but also road handling by minimizing the dynamics of the wheels normal forces. It may enhance vehicle stability by controlling the wheel load distribution, which influences the lateral and longitudinal dynamics to provide better steering performance, and safety by reducing the braking distance. The main contribution of this paper is to study the impact of fractional order (FO) control methods in the context of an active suspension system and in particular fractional order damping control. We derive two optimal damping control strategies: a comfort-oriented and a road holding oriented strategy, based on non-integer derivation of suspension deflection. The relevant benefits of both methods on vehicle response while driving on rough roads and during braking are evaluated using computer simulations applied on a two-wheel vehicle model.

IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society, 2021

This paper presents a new Energy Management System (EMS) strategy for the Energy Storage System (... more This paper presents a new Energy Management System (EMS) strategy for the Energy Storage System (ESS) of a Microgrid (MG) based on the proper time scale of each ESS component. The theoretical framework allows to achieve more efficient use of the different ESS components’. While almost all existing methods rely on filtering load profile signals to achieve power separation, our proposed approach achieves a better performance on components’ ageing rate with less processing complexity using a simple limiter in algorithm. The proposed method is first evaluated as an EMS only and then extended to the whole MG. Results show an ageing rate reduction of 93% for fast component at the price of 24% of ageing rate increase for slow component.

SSRN Electronic Journal, 2022

IEEE Transactions on Aerospace and Electronic Systems, 2011

2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

In this paper, a new robust model-based supertwisting algorithm is proposed as a control solution... more In this paper, a new robust model-based supertwisting algorithm is proposed as a control solution for parallel kinematic manipulators (PKMs). The conventional supertwisting algorithm for robot manipulators has the structure of a computed-torque control which can be sensitive to measurement noise. This issue may deteriorate the dynamic performance of the manipulator and reduce its robustness towards changes in the operating conditions. The proposed approach, relying on the desired trajectory, is more computationally efficient and more robust. It includes a feedforward dynamic compensator, the super-twisting feedback control, and a feedback stabilizing term. As a validation, real-time experiments have been conducted on a 5-DOF redundantly actuated PKM. Several scenarios have been tested including nominal case and the robustness towards speed variations. The relevance of the proposed control solution is proved through the improvement of the tracking performance at different dynamic operating conditions.

IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society, 2021

In this paper, we present a robust nonlinear de-centralized control scheme for an islanded DC mic... more In this paper, we present a robust nonlinear de-centralized control scheme for an islanded DC microgrid (MG) where the main control goals are to achieve a sustained stability for the DC bus voltage at a certain desired value, to maintain the power balance in the system and to insure robustness against disturbances and perturbations. The proposed control strategy uses the Model Free Super-Twisting Sliding Mode (MFSMC) as it needs no accurate representation of the environment in order to be effective which makes it a suitable choice for system with nonlinear model prone to parameters variation. The studied microgrid is composed of a solar photo-voltaic (PV) unit and a hybrid energy storage system including a battery and a supercapacitor (SC) along with DC loads. To attain the intended objectives, a hierarchical cascaded control strategy is designed with two levels: a high-level control that stabilizes the DC bus voltage at a reference value by generating a current reference to be tracked, and a low-level control composed of an energy management system EMS based on a passive filtration to distribute the reference current between the storage system units according to their dynamic specifications. Simulations on MATLAB/Simulink are carried out to evaluate the effectiveness and robustness of the proposed control scheme under various operating conditions created by random variations of power generation and consumption. Noise sensitivity test is also carried out for this controller and for a model-based one that is the Feedback linearization control technique (FL).

International Journal of Control, 2019

This study focuses on the development of a new class of the Robust Integral of the Sign of the Er... more This study focuses on the development of a new class of the Robust Integral of the Sign of the Error (RISE) control law adequate for second-order nonlinear multiinput-multi-output systems. A revisit for the original RISE is done by altering some static feedback gains into time-varying nonlinear ones depending on the system states. The proposed controller takes advantage of both RISE control robustness towards uncertainties and the special behavior of nonlinear feedback gains towards time-varied parameters. A Lyaponuv-based stability analysis to prove the semiglobal asymptotic tracking of the proposed new controller is included. In order to validate the relevance of the proposed controller, real-time experimental results are presented and discussed. Experiments have been conducted on a Delta parallel manipulator, in different operating conditions including payload and speed variations.

SAE International Journal of Aerospace

Publication in the conference proceedings of EUSIPCO, Barcelona, Spain, 2011

2018 7th European Workshop on Visual Information Processing (EUVIP), 2018

In this work, we evaluate different classification algorithms used for multi-target detection in ... more In this work, we evaluate different classification algorithms used for multi-target detection in hyperspectral imaging. We took into consideration the scenario of landmine detection in which we compared the performance of each method in various cases. In addition, we introduced the detection of targets using artificial intelligence-based methods in order to obtain better detection performance together with target identification and estimation of its abundance. These algorithms were tested on various types of hyperspectral images where the spectra of the landmines were planted in different proportions in the hyperspectral scenes. The results show the advantage of using our training strategy for radial basis function neural networks (RBFNN) in order to detect, identify and estimate the abundance of the targets in hyperspectral images at the same time. Moreover, the proposed technique requires a comparable computational cost with respect to state of art target detection techniques.

Nasa Sti Recon Technical Report N, Aug 1, 1985

Abstract : A broadband cable system was installed at U.S. Army Combat Systems Test Activity (USAC... more Abstract : A broadband cable system was installed at U.S. Army Combat Systems Test Activity (USACSTA) in 1980 to allow data communication between test site data acquisition systems. The high-speed modems selected for this function were found to be unreliable and unmaintainable. This project was to investigate alternative equipment which would be suitable for providing high-speed data communications on the USACSTA broadband cable system. The investigation was conducted at USACSTA from May 1983 to August 1985. It is concluded that (1) The Fairchild Data Corporation M505 provides the flexibility, reliability, and maintainability required for the USACSTA broadband network; (2) The best network topology consists of using a computer at Building 436 to perform network routing and not using a translator; (3) Routine preventive maintenance must be performed on the broadband cable system to maintain its effectiveness; (4) The CATEL DM-2100 provides adequate low-speed peformance; (5) Additional cable drops must be provided to meet user needs; (6) An improved software data transfer utility must be created to support the broadband cable system requirements; (7) The addition of an audio-communications capability to the broadband cable system would increase its utility and improve range communications. (Author)

Abstract : At the present time automotive test data relative to use and operational environment i... more Abstract : At the present time automotive test data relative to use and operational environment is gathered by tachographs, analog tape recorders, and pulse code modulation (PCM) encoders. This project was to develop a Vehicle Performance Recorder (VPR) to augment the existing automotive test capability. The design objectives of the VPR were: self-contained, analog and digital inputs, digital recording, programmable, not require an on site or skilled operator, 8-hour capacity, 0.1% analog accuracy, 30-second time resolution, useable in US Army Aberdeen Proving Ground (APG) environment, 28 VDC operation, and internal battery operation. A unit which meets these objectives is described in detail. The VPR uses a commercial cassette recorder and a custom controller to provide a flexible, low-power consumption data acquisition system. A description of alternative systems is also provided. It is concluded that: (a) the VPR satisfies a wide variety of measurement needs; (b) commercially manufactured units now exist with a wide spectrum of capabilities; (c) the Army developed Vehicle Monitoring System (VMS) may be available in the future; (d) no single unit satisfies all possible data acquisition requirements. It is recommended that a commercially available unit be used if possible; if not then the VPR be used. (Author)

Journal of Applied Physics, 1995

2022 International Conference on Unmanned Aircraft Systems (ICUAS)

IEEE Transactions on Vehicular Technology

2019 IEEE Intelligent Vehicles Symposium (IV), 2019

In this paper, we focused on the yaw motion dynamics for light electric vehicles. The objective i... more In this paper, we focused on the yaw motion dynamics for light electric vehicles. The objective is to track the yaw rate reference in order to enhance lateral stability. Two controllers were designed, a simple PID controller and a third generation CRONE controller. The design methodology considers the total mass of the vehicle, the longitudinal speed, and the road adhesion as uncertain parameters. Later, we analyze the effect of vertical dynamics, on a controlled full vehicle system, where the variation of the normal wheel-contact forces was taken into consideration. A double lane change maneuver is simulated, and the results show the robustness of the CRONE controller against the uncertain parameters and its effectiveness to lessens the influence of load transfer variations.

2019 4th Conference on Control and Fault Tolerant Systems (SysTol), 2019

This paper considers a distributed planner method for multiple unmanned aerial vehicles (UAV), ba... more This paper considers a distributed planner method for multiple unmanned aerial vehicles (UAV), based on a leaderless approach, using an Artificial Bee Colony (ABC) optimization algorithm. The ABC algorithm is a metaheuristic optimization method inspired by the intelligent behavior of the honeybee swarm. The proposed ABC, implemented on each UAV independently, is used to compute velocity profiles that avoid obstacles and collisions between the UAVs while ensuring the fleet formation control and the target tracking. The proposed algorithm is demonstrated by simulations on Matlab/Simulink in different scenarios.

IFAC-PapersOnLine, 2018

In this paper, the standard PID controller and the fractional first generation CRONE controller a... more In this paper, the standard PID controller and the fractional first generation CRONE controller are applied on the anti-roll moment system to improve ride comfort for passengers in the frame of global chassis control of electric vehicles. A comparative study is done showing the performance and the robustness of the two controllers, in frequency and time domain. It is shown that the first generation CRONE control-system is able to provide robust fractional order controller for uncertain perturbed plants.

IFAC-PapersOnLine, 2019

Active suspensions are an object of interest nowadays, they have been a topic of research for dec... more Active suspensions are an object of interest nowadays, they have been a topic of research for decades due to their key role in Global Chassis Control (GCC). Indeed, a wellcontrolled active suspension system may considerably improve not only the passenger comfort by compensating the chassis dynamics but also road handling by minimizing the dynamics of the wheels normal forces. It may enhance vehicle stability by controlling the wheel load distribution, which influences the lateral and longitudinal dynamics to provide better steering performance, and safety by reducing the braking distance. The main contribution of this paper is to study the impact of fractional order (FO) control methods in the context of an active suspension system and in particular fractional order damping control. We derive two optimal damping control strategies: a comfort-oriented and a road holding oriented strategy, based on non-integer derivation of suspension deflection. The relevant benefits of both methods on vehicle response while driving on rough roads and during braking are evaluated using computer simulations applied on a two-wheel vehicle model.

IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society, 2021

This paper presents a new Energy Management System (EMS) strategy for the Energy Storage System (... more This paper presents a new Energy Management System (EMS) strategy for the Energy Storage System (ESS) of a Microgrid (MG) based on the proper time scale of each ESS component. The theoretical framework allows to achieve more efficient use of the different ESS components’. While almost all existing methods rely on filtering load profile signals to achieve power separation, our proposed approach achieves a better performance on components’ ageing rate with less processing complexity using a simple limiter in algorithm. The proposed method is first evaluated as an EMS only and then extended to the whole MG. Results show an ageing rate reduction of 93% for fast component at the price of 24% of ageing rate increase for slow component.

SSRN Electronic Journal, 2022

IEEE Transactions on Aerospace and Electronic Systems, 2011

2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

In this paper, a new robust model-based supertwisting algorithm is proposed as a control solution... more In this paper, a new robust model-based supertwisting algorithm is proposed as a control solution for parallel kinematic manipulators (PKMs). The conventional supertwisting algorithm for robot manipulators has the structure of a computed-torque control which can be sensitive to measurement noise. This issue may deteriorate the dynamic performance of the manipulator and reduce its robustness towards changes in the operating conditions. The proposed approach, relying on the desired trajectory, is more computationally efficient and more robust. It includes a feedforward dynamic compensator, the super-twisting feedback control, and a feedback stabilizing term. As a validation, real-time experiments have been conducted on a 5-DOF redundantly actuated PKM. Several scenarios have been tested including nominal case and the robustness towards speed variations. The relevance of the proposed control solution is proved through the improvement of the tracking performance at different dynamic operating conditions.

IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society, 2021

In this paper, we present a robust nonlinear de-centralized control scheme for an islanded DC mic... more In this paper, we present a robust nonlinear de-centralized control scheme for an islanded DC microgrid (MG) where the main control goals are to achieve a sustained stability for the DC bus voltage at a certain desired value, to maintain the power balance in the system and to insure robustness against disturbances and perturbations. The proposed control strategy uses the Model Free Super-Twisting Sliding Mode (MFSMC) as it needs no accurate representation of the environment in order to be effective which makes it a suitable choice for system with nonlinear model prone to parameters variation. The studied microgrid is composed of a solar photo-voltaic (PV) unit and a hybrid energy storage system including a battery and a supercapacitor (SC) along with DC loads. To attain the intended objectives, a hierarchical cascaded control strategy is designed with two levels: a high-level control that stabilizes the DC bus voltage at a reference value by generating a current reference to be tracked, and a low-level control composed of an energy management system EMS based on a passive filtration to distribute the reference current between the storage system units according to their dynamic specifications. Simulations on MATLAB/Simulink are carried out to evaluate the effectiveness and robustness of the proposed control scheme under various operating conditions created by random variations of power generation and consumption. Noise sensitivity test is also carried out for this controller and for a model-based one that is the Feedback linearization control technique (FL).

International Journal of Control, 2019

This study focuses on the development of a new class of the Robust Integral of the Sign of the Er... more This study focuses on the development of a new class of the Robust Integral of the Sign of the Error (RISE) control law adequate for second-order nonlinear multiinput-multi-output systems. A revisit for the original RISE is done by altering some static feedback gains into time-varying nonlinear ones depending on the system states. The proposed controller takes advantage of both RISE control robustness towards uncertainties and the special behavior of nonlinear feedback gains towards time-varied parameters. A Lyaponuv-based stability analysis to prove the semiglobal asymptotic tracking of the proposed new controller is included. In order to validate the relevance of the proposed controller, real-time experimental results are presented and discussed. Experiments have been conducted on a Delta parallel manipulator, in different operating conditions including payload and speed variations.

SAE International Journal of Aerospace

Publication in the conference proceedings of EUSIPCO, Barcelona, Spain, 2011