Salih ABDELAZIZ - Academia.edu (original) (raw)

Papers by Salih ABDELAZIZ

2020 IEEE International Conference on Robotics and Automation (ICRA), 2020

This paper introduces a 2-DOF spatial remote center of motion (RCM) tensegrity mechanism, based o... more This paper introduces a 2-DOF spatial remote center of motion (RCM) tensegrity mechanism, based on a double parallelogram system, dedicated for percutaneous needle insertion. The originality of this mechanism is its ability to be reconfigured and its capacity to perform a decoupled modulation of its stiffness in an asynchronous way. To do so, an analytical stiffness model of the robot is established, and a control methodology is proposed. A prototype of the robot is developed and assessed experimentally. The position tracking is evaluated using a 6-DOF magnetic tracker sensor showing a root mean square error less than 0.8 • in both directions of the needle guide.

Mechanism and Machine Theory, 2017

Cable-driven systems are of great interest in applications for which remote actuation is required... more Cable-driven systems are of great interest in applications for which remote actuation is required, like for instance to operate within medical imaging devices. In such applications, robotic architectures based on remotely actuated cable-driven manipulators (CDM) offer innovative design options. However, unlike more conventional CDM, such designs involve specific control problems. This paper deals with the control of CDM in the presence of friction, as experienced when particular design constraints have to be taken into account (size, materials, length of transmissions). In this case, the influence of friction on the manipulator motions is such that dynamic modeling, identification and control, are no longer adapted, nor even possible. As a result, for quasi-static positioning tasks, we propose a CDM position control strategy resulting from a cascade structure, with an internal cable tension control loop to handle friction. Cable tension is measured using an original instrumented compliant structure. From the control point of view, the originality of the present paper comes in particular from the development of a feasibility algorithm which allows us to limit cables tensions within a specified range. This strategy is experimentally assessed on a robot for image-guided medical procedures.

In this paper, we present the design of a novel MR-compatible needle holder with variable stiffne... more In this paper, we present the design of a novel MR-compatible needle holder with variable stiffness and a first experimental evaluation of its ability to be controlled in position and stiffness. The device should be able to control both the orientation and the angular stiffness of the needle around the insertion point within the MR-environment. To do so, our design is based on tensegrity mechanisms, a class of prestressed mechanisms that exhibit interesting properties for our context since they are compact, lightweight and remotely controllable. An experimental setup is developed. The position and stiffness control on one degree of freedom is then performed using an open loop control strategy. Encouraging results are finally presented as well as future works to be carried out.

La realisation de gestes percutanes dans l’IRM ouvre la voie a des pratiques medicales prometteus... more La realisation de gestes percutanes dans l’IRM ouvre la voie a des pratiques medicales prometteuses. En revanche, l’utilisation de l’IRM reste a ce jour limitee, et ce malgre l’interet en terme de qualite d’image. Cela est du principalement a l’etroitesse du tunnel et a la complexite des gestes realises. Pour rendre accessibles de telles pratiques, une assistance robotique semble tres pertinente. Pour le concepteur, la realisation d’un systeme robotise compatible IRM n’est pas une tâche facile, etant donne l’espace disponible et la presence d’un champ magnetique intense. C'est dans ce contexte que nous avons developpe un assistant robotique, MRGuide, dedie aux traitements du cancer de la prostate dans l’IRM. Il s'agit d'un manipulateur a câbles avec un actionnement deporte. Dans ce travail, de nombreuses contributions menant a la realisation de ce prototypes ont presentees. Parmi celles‐ci, une instrumentation originale pour estimer la tension des câbles est proposee. Ce...

INTED2019 Proceedings, 2019

The eHealth Eurocampus project, an EU-funded project, aims at preparing innovative professionals ... more The eHealth Eurocampus project, an EU-funded project, aims at preparing innovative professionals able to cope with the challenge of fostering a spirit of innovation in eHealth in Europe as the way forward to ensure better health and better and safer care. The main objectives of the eHealth Eurocampus are improving the relevance and quality of higher education in the field of ICT applications for health, and fostering employability through curricula adaptation to labour market needs and the development of entrepreneurship skills. In the frame of this project we are developing course materials, and implementing new and innovative teaching methods that are tested through joint learning activities (summer schools), which will be used later on in different master courses. The project includes the organization of training seminars to exchange good practices and knowledge among teachers and researchers. The eHealth Eurocampus consortium includes 8 higher education institutions, a regional ...

Precise trajectory tracking and stiffness modulation for tensegrity mechanisms are a challenging ... more Precise trajectory tracking and stiffness modulation for tensegrity mechanisms are a challenging topic that can open new horizon of applications for this type of systems. This paper presents a new control strategy of tensegrity mechanisms using a model predictive controller (MPC). Based on a dynamic model, the proposed approach allows to track trajectories with low and relatively high dynamics as well as to modulate the mechanism stiffness by changing only the controller’s parameters. Trajectories of 30 s, 5 s and 1 s are performed showing a trajectory tracking improvement of up to \(64\%\) in the root mean square error when compared to literature results.

Introduction The field of MR imaging has extended from diagnosis to guidance and control in a wid... more Introduction The field of MR imaging has extended from diagnosis to guidance and control in a wide variety of interventional procedures [1]. Due to the lack of space and manipulability within the MRI scanner, there is an ongoing interest for robotic assistance in MR-guided interventions. Numerous MR-compatible robots have been proposed, especially for needle manipulation. For needle insertion in the liver, patient-mounted robots are particularly interesting for the pro- vided partial compensation of the breathing motion. The needle holder must however still fulfill two contradictory requirements: it needs to be stiff during the insertion and compliant afterwards, in order to avoid organ lacerations [2]. This led to the development of needle grasping systems that allow the needle to move freely between two insertion phases [3]. In this paper, an alternate approach is considered: a needle manipulation system with adaptive compliance is proposed that is based on so-called tensegrity me...

This paper deals with the impact of the design parameters on the static workspace and the stiffne... more This paper deals with the impact of the design parameters on the static workspace and the stiffness range of a planar 3-DoF tensegrity mechanism. The static model is established through the energetic approach and the stiffness is derived analytically along the 3-DoF of the mechanism. The design parameters considered here are the spring stiffness and the location of the mechanism attachment points to the base. Results on the impact of these parameters are finally analyzed. This analysis constitutes a first step towards the geometric optimization of tensegrity mechanisms.

Cable-driven tensegrity mechanisms can be considered to control at the same time position and sti... more Cable-driven tensegrity mechanisms can be considered to control at the same time position and stiffness. Adequate control solutions have however not been proposed yet. This paper focuses on the development of an original control method using a tension distribution algorithm adapted from related work on cable-driven mechanisms. The algorithm is being used to modify the mechanism configuration together with its stiffness through the level of prestress in the system, which constitutes a step towards the exploitation of such mechanisms for variable stiffness applications. Simulations show encouraging results on the stiffness variation capacity of the presented mechanism.

Robotique

Les mecanismes de tensegrite sont issus des tensegrites, une classe de structures precontraintes ... more Les mecanismes de tensegrite sont issus des tensegrites, une classe de structures precontraintes pouvant supporter des charges importantes tout en restant legeres et compliantes. Leur exploitation en robotique de manipulation presente de nombreux interets, tout particulierement pour la robotique d’interaction. L’article introduit ces systemes, en fournissant des elements d’analyse, de conception et de commande indispensables a leur exploitation dans ce contexte. Leurs differentes applications en robotique de manipulation, ainsi que les defis technologiques et fondamentaux associes a leur exploitation sont egalement introduits.

Journal of Pressure Vessel Technology, 2013

High-pressure measurements in most scientific fields rely on metal vessels, a consequence of the ... more High-pressure measurements in most scientific fields rely on metal vessels, a consequence of the superior tensile strength of metals. Magnetic resonance imaging in conjunction with metallic pressure vessels has recently been introduced. Magnetic resonance imaging with compatible metallic pressure vessels is a very general concept. This paper outlines the specifics of the development and design of these vessels. Metallic pressure vessels not only provide inherently high tensile strengths and efficient temperature control, they also permit optimization of the radio-frequency probe sensitivity. The design and application of magnetic resonance imaging compatible pressure vessels is illustrated through a rock core holder fabricated using nonmagnetic stainless steel. Water flooding through a porous rock at elevated pressure and temperature is shown as an example of its applications. High-pressure magnetic resonance plays an indispensable role in several scientific fields; this work will o...

EDULEARN19 Proceedings, Jul 1, 2019

The aim of this paper is to present the results of an initiative called the eHealth Eurocampus (h... more The aim of this paper is to present the results of an initiative called the eHealth Eurocampus (http://ehealtheurocampus.eu), whose main goal is to define a framework to prepare professionals for the eHealth work environment. To do so, three main activities have been organized: develop eHealth learning materials, international intensive study programs for both health science and IT students and international training seminars for researches and professors. The consortium of the eHealth Eurocampus project along with the participants of the designed activities have created an original eHealth teaching-learning framework where university professors, students, researchers, and clinicians are able to share their experiences and knowledge with the aim of improving the skills of graduates in order to improve their employability.

IEEE Transactions on Radiation and Plasma Medical Sciences

Mechanism and Machine Theory

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Mechanism and Machine Theory

Cable-driven tensegrity mechanisms are now considered for various applications in which their rec... more Cable-driven tensegrity mechanisms are now considered for various applications in which their reconfiguration capacities are required together with their inherent lightness. Moreover, they can exhibit interesting variable stiffness capacities through the modification of their level of prestress when composed of deformable cables. Control schemes that deal with both reconfiguration and stiffness variation have however not been developed in the literature yet. This paper presents two control strategies for that purpose to transform a cable-driven tensegrity mechanism into a variable stiffness device. The mechanism is a planar tensegrity mechanism allowing us to control an angular position and the associated stiffness. Relying on the properties of the mechanism models, the proposed control strategies allow a modulation of the stiffness or of its first time derivative. The interest of both propositions is outlined and an experimental investigation of their characteristics is performed. Encouraging results are obtained in terms of reconfiguration capabilities and stiffness variation.

2016 IEEE International Conference on Robotics and Automation (ICRA), 2016

In this paper, the design of a new variable stiffness spherical joint for MR-compatible robotics ... more In this paper, the design of a new variable stiffness spherical joint for MR-compatible robotics is presented. It is based on the use of prestressed cable-driven mechanisms in singular configurations to provide large stiffness variation ranges, including zero stiffness configuration as required by the medical context. An original implementation is proposed, with a prestress adjustment system using pneumatic energy and taking advantage of multimaterial additive manufacturing. The proposed component combines compactness, MR-compatibility and is lightweight. The system is evaluated on a dedicated experimental setup with validation of the expected behavior, with in particular a very large achievable range of stiffnesses. The approach is effective for the design of such device and constitutes a novel solution for the design of variable stiffness devices with complex motions.

Http Www Theses Fr, Nov 29, 2012

Volume 5A: 39th Mechanisms and Robotics Conference, 2015

2020 IEEE International Conference on Robotics and Automation (ICRA), 2020

This paper introduces a 2-DOF spatial remote center of motion (RCM) tensegrity mechanism, based o... more This paper introduces a 2-DOF spatial remote center of motion (RCM) tensegrity mechanism, based on a double parallelogram system, dedicated for percutaneous needle insertion. The originality of this mechanism is its ability to be reconfigured and its capacity to perform a decoupled modulation of its stiffness in an asynchronous way. To do so, an analytical stiffness model of the robot is established, and a control methodology is proposed. A prototype of the robot is developed and assessed experimentally. The position tracking is evaluated using a 6-DOF magnetic tracker sensor showing a root mean square error less than 0.8 • in both directions of the needle guide.

Mechanism and Machine Theory, 2017

Cable-driven systems are of great interest in applications for which remote actuation is required... more Cable-driven systems are of great interest in applications for which remote actuation is required, like for instance to operate within medical imaging devices. In such applications, robotic architectures based on remotely actuated cable-driven manipulators (CDM) offer innovative design options. However, unlike more conventional CDM, such designs involve specific control problems. This paper deals with the control of CDM in the presence of friction, as experienced when particular design constraints have to be taken into account (size, materials, length of transmissions). In this case, the influence of friction on the manipulator motions is such that dynamic modeling, identification and control, are no longer adapted, nor even possible. As a result, for quasi-static positioning tasks, we propose a CDM position control strategy resulting from a cascade structure, with an internal cable tension control loop to handle friction. Cable tension is measured using an original instrumented compliant structure. From the control point of view, the originality of the present paper comes in particular from the development of a feasibility algorithm which allows us to limit cables tensions within a specified range. This strategy is experimentally assessed on a robot for image-guided medical procedures.

In this paper, we present the design of a novel MR-compatible needle holder with variable stiffne... more In this paper, we present the design of a novel MR-compatible needle holder with variable stiffness and a first experimental evaluation of its ability to be controlled in position and stiffness. The device should be able to control both the orientation and the angular stiffness of the needle around the insertion point within the MR-environment. To do so, our design is based on tensegrity mechanisms, a class of prestressed mechanisms that exhibit interesting properties for our context since they are compact, lightweight and remotely controllable. An experimental setup is developed. The position and stiffness control on one degree of freedom is then performed using an open loop control strategy. Encouraging results are finally presented as well as future works to be carried out.

La realisation de gestes percutanes dans l’IRM ouvre la voie a des pratiques medicales prometteus... more La realisation de gestes percutanes dans l’IRM ouvre la voie a des pratiques medicales prometteuses. En revanche, l’utilisation de l’IRM reste a ce jour limitee, et ce malgre l’interet en terme de qualite d’image. Cela est du principalement a l’etroitesse du tunnel et a la complexite des gestes realises. Pour rendre accessibles de telles pratiques, une assistance robotique semble tres pertinente. Pour le concepteur, la realisation d’un systeme robotise compatible IRM n’est pas une tâche facile, etant donne l’espace disponible et la presence d’un champ magnetique intense. C'est dans ce contexte que nous avons developpe un assistant robotique, MRGuide, dedie aux traitements du cancer de la prostate dans l’IRM. Il s'agit d'un manipulateur a câbles avec un actionnement deporte. Dans ce travail, de nombreuses contributions menant a la realisation de ce prototypes ont presentees. Parmi celles‐ci, une instrumentation originale pour estimer la tension des câbles est proposee. Ce...

INTED2019 Proceedings, 2019

The eHealth Eurocampus project, an EU-funded project, aims at preparing innovative professionals ... more The eHealth Eurocampus project, an EU-funded project, aims at preparing innovative professionals able to cope with the challenge of fostering a spirit of innovation in eHealth in Europe as the way forward to ensure better health and better and safer care. The main objectives of the eHealth Eurocampus are improving the relevance and quality of higher education in the field of ICT applications for health, and fostering employability through curricula adaptation to labour market needs and the development of entrepreneurship skills. In the frame of this project we are developing course materials, and implementing new and innovative teaching methods that are tested through joint learning activities (summer schools), which will be used later on in different master courses. The project includes the organization of training seminars to exchange good practices and knowledge among teachers and researchers. The eHealth Eurocampus consortium includes 8 higher education institutions, a regional ...

Precise trajectory tracking and stiffness modulation for tensegrity mechanisms are a challenging ... more Precise trajectory tracking and stiffness modulation for tensegrity mechanisms are a challenging topic that can open new horizon of applications for this type of systems. This paper presents a new control strategy of tensegrity mechanisms using a model predictive controller (MPC). Based on a dynamic model, the proposed approach allows to track trajectories with low and relatively high dynamics as well as to modulate the mechanism stiffness by changing only the controller’s parameters. Trajectories of 30 s, 5 s and 1 s are performed showing a trajectory tracking improvement of up to \(64\%\) in the root mean square error when compared to literature results.

Introduction The field of MR imaging has extended from diagnosis to guidance and control in a wid... more Introduction The field of MR imaging has extended from diagnosis to guidance and control in a wide variety of interventional procedures [1]. Due to the lack of space and manipulability within the MRI scanner, there is an ongoing interest for robotic assistance in MR-guided interventions. Numerous MR-compatible robots have been proposed, especially for needle manipulation. For needle insertion in the liver, patient-mounted robots are particularly interesting for the pro- vided partial compensation of the breathing motion. The needle holder must however still fulfill two contradictory requirements: it needs to be stiff during the insertion and compliant afterwards, in order to avoid organ lacerations [2]. This led to the development of needle grasping systems that allow the needle to move freely between two insertion phases [3]. In this paper, an alternate approach is considered: a needle manipulation system with adaptive compliance is proposed that is based on so-called tensegrity me...

This paper deals with the impact of the design parameters on the static workspace and the stiffne... more This paper deals with the impact of the design parameters on the static workspace and the stiffness range of a planar 3-DoF tensegrity mechanism. The static model is established through the energetic approach and the stiffness is derived analytically along the 3-DoF of the mechanism. The design parameters considered here are the spring stiffness and the location of the mechanism attachment points to the base. Results on the impact of these parameters are finally analyzed. This analysis constitutes a first step towards the geometric optimization of tensegrity mechanisms.

Cable-driven tensegrity mechanisms can be considered to control at the same time position and sti... more Cable-driven tensegrity mechanisms can be considered to control at the same time position and stiffness. Adequate control solutions have however not been proposed yet. This paper focuses on the development of an original control method using a tension distribution algorithm adapted from related work on cable-driven mechanisms. The algorithm is being used to modify the mechanism configuration together with its stiffness through the level of prestress in the system, which constitutes a step towards the exploitation of such mechanisms for variable stiffness applications. Simulations show encouraging results on the stiffness variation capacity of the presented mechanism.

Robotique

Les mecanismes de tensegrite sont issus des tensegrites, une classe de structures precontraintes ... more Les mecanismes de tensegrite sont issus des tensegrites, une classe de structures precontraintes pouvant supporter des charges importantes tout en restant legeres et compliantes. Leur exploitation en robotique de manipulation presente de nombreux interets, tout particulierement pour la robotique d’interaction. L’article introduit ces systemes, en fournissant des elements d’analyse, de conception et de commande indispensables a leur exploitation dans ce contexte. Leurs differentes applications en robotique de manipulation, ainsi que les defis technologiques et fondamentaux associes a leur exploitation sont egalement introduits.

Journal of Pressure Vessel Technology, 2013

High-pressure measurements in most scientific fields rely on metal vessels, a consequence of the ... more High-pressure measurements in most scientific fields rely on metal vessels, a consequence of the superior tensile strength of metals. Magnetic resonance imaging in conjunction with metallic pressure vessels has recently been introduced. Magnetic resonance imaging with compatible metallic pressure vessels is a very general concept. This paper outlines the specifics of the development and design of these vessels. Metallic pressure vessels not only provide inherently high tensile strengths and efficient temperature control, they also permit optimization of the radio-frequency probe sensitivity. The design and application of magnetic resonance imaging compatible pressure vessels is illustrated through a rock core holder fabricated using nonmagnetic stainless steel. Water flooding through a porous rock at elevated pressure and temperature is shown as an example of its applications. High-pressure magnetic resonance plays an indispensable role in several scientific fields; this work will o...

EDULEARN19 Proceedings, Jul 1, 2019

The aim of this paper is to present the results of an initiative called the eHealth Eurocampus (h... more The aim of this paper is to present the results of an initiative called the eHealth Eurocampus (http://ehealtheurocampus.eu), whose main goal is to define a framework to prepare professionals for the eHealth work environment. To do so, three main activities have been organized: develop eHealth learning materials, international intensive study programs for both health science and IT students and international training seminars for researches and professors. The consortium of the eHealth Eurocampus project along with the participants of the designed activities have created an original eHealth teaching-learning framework where university professors, students, researchers, and clinicians are able to share their experiences and knowledge with the aim of improving the skills of graduates in order to improve their employability.

IEEE Transactions on Radiation and Plasma Medical Sciences

Mechanism and Machine Theory

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Mechanism and Machine Theory

Cable-driven tensegrity mechanisms are now considered for various applications in which their rec... more Cable-driven tensegrity mechanisms are now considered for various applications in which their reconfiguration capacities are required together with their inherent lightness. Moreover, they can exhibit interesting variable stiffness capacities through the modification of their level of prestress when composed of deformable cables. Control schemes that deal with both reconfiguration and stiffness variation have however not been developed in the literature yet. This paper presents two control strategies for that purpose to transform a cable-driven tensegrity mechanism into a variable stiffness device. The mechanism is a planar tensegrity mechanism allowing us to control an angular position and the associated stiffness. Relying on the properties of the mechanism models, the proposed control strategies allow a modulation of the stiffness or of its first time derivative. The interest of both propositions is outlined and an experimental investigation of their characteristics is performed. Encouraging results are obtained in terms of reconfiguration capabilities and stiffness variation.

2016 IEEE International Conference on Robotics and Automation (ICRA), 2016

In this paper, the design of a new variable stiffness spherical joint for MR-compatible robotics ... more In this paper, the design of a new variable stiffness spherical joint for MR-compatible robotics is presented. It is based on the use of prestressed cable-driven mechanisms in singular configurations to provide large stiffness variation ranges, including zero stiffness configuration as required by the medical context. An original implementation is proposed, with a prestress adjustment system using pneumatic energy and taking advantage of multimaterial additive manufacturing. The proposed component combines compactness, MR-compatibility and is lightweight. The system is evaluated on a dedicated experimental setup with validation of the expected behavior, with in particular a very large achievable range of stiffnesses. The approach is effective for the design of such device and constitutes a novel solution for the design of variable stiffness devices with complex motions.

Http Www Theses Fr, Nov 29, 2012

Volume 5A: 39th Mechanisms and Robotics Conference, 2015