Frédéric Boyer | EMN - Academia.edu (original) (raw)
Conference Papers by Frédéric Boyer
Conference: 19ème Congrès Français de Mécanique [CFM2009], Marseille, France, Aug 24, 2009
Cet article présente le couplage du solveur fluide ISIS-CFD du LMF et d’un solveur structure de t... more Cet article présente le couplage du solveur fluide ISIS-CFD du LMF et d’un solveur structure de type poutre appliqué à des problèmes 3D complexes d’interaction fluide-structure des corps élancés en grand déplacement, comme les risers. Le couplage temporel s’appuie sur un algorithme itératif. Un soin tout particulier a été porté au couplage spatial, en particulier au processus de déformation de maillage. Afin de valider le code IFS, le cas-test 2D d’Hübner a été traité.
In this paper the coupling of a structural solver for elongated structures in large displacements with the flow solver ISIS-CFD is presented. ISIS-CFD is a 3-D finite volume solver based on the incompressible unsteady Reynolds-averaged Navier-Stokes equations, developed by the CFD group of the Fluid Mechanics Laboratory. The finite element structural solver uses Euler-Bernoulli or Rayleigh kinematics with the Cosserat hypothesis. The time coupling uses an iterative algorithm. Special attention to the space coupling, in particular the remeshing procedure. This coupling algorithm is first validated and then applied to the 2-D Hübner test case.
Papers by Frédéric Boyer
This paper presents a reduced mean model of a three-dimensional Eel-like robot. Such a robot is u... more This paper presents a reduced mean model of a three-dimensional Eel-like robot. Such a robot is under construction in the context of a national French robotic project. This model is based on mechanical considerations as well as on our experience with an existing 3D continuous model of the target prototype. Identification and validation of the dynamic model are presented here.
Procedia CIRP, 2018
The piping inspection for security or sealing checking is an important challenge when the interna... more The piping inspection for security or sealing checking is an important challenge when the internal diameter of the pipe is small with respect to its length. Some mechanisms using closed loops are able to generate contact forces and deployable structures. By using bio-inspired design, we present a mechanism which is able to move inside pipes by mimicking the motion of a caterpillar. The mechanism is composed of three sections, one for the motion and two with legs that are attached with the inner part of the pipe. A compliant mechanism is proposed to add mobility between the three sections of the robot in order to cross the singularity of the pipe. The results coming from a multi-objective optimization process is used to set the geometric and kinematic parameters of the mechanism taking into account the environmental and design constraints. A mechatronic system is proposed that uses industrial components namely DC motors, ball-screws and servo controllers which can be inserted in the pipe. For horizontal and vertical motions, the contact forces and the motor torques are computed to check the feasibility of the clamping. A prototype made at Laboratoire des Sciences du Numérique de Nantes (LS2N) is used to show the behavior of this concept for slow motions.
Techniques De L Ingenieur Informatique Industrielle, 2006
The International Journal of Robotics Research, 2020
This article exploits a bio-inspired sensor technology named artificial electric-sense to emulate... more This article exploits a bio-inspired sensor technology named artificial electric-sense to emulate underwater pre-touch. The sensor is considered as an electric finger controlled remotely by an operator to follow the boundaries of objects. Using electric measurements only, the approach feeds back pre-touch forces and torques to the operator through an haptic interface. These forces and torques are generated by a set of virtual electric charges and dipoles arranged on the probe and reacting in the electric field reflected by the objects. This model of emulated forces is passive and guarantees the stability of a position–position haptic feedback loop. The whole approach is assessed through a set of experiments carried out on a Cartesian slave robot coupled to an haptic interface. The obtained results show the feasibility of the concept and its robustness to different configurations of objects. Such an electro-haptic feedback opens new perspectives in both electric field sensing and und...
Oxford Scholarship Online, 2018
Underwater navigation in turbid water for exploration in catastrophic conditions or navigation in... more Underwater navigation in turbid water for exploration in catastrophic conditions or navigation in confined unstructured environments is still a challenge for robotics. In these conditions, neither vision nor sonar can be used. Pursuing a bio-inspired approach in robotics, one can seek solutions in nature to solve this difficult problem. Several hundred fish species in families Gymnotidae and Mormyridae have developed an original sense well adapted to this situation: the electric sense. Gnathonemus petersii first polarizes its body with respect to an electric organ discharge located at the base of its tail and generates a dipolar electric field in its near surroundings. Then, using many transcutaneous electro-receptors distributed along its body, the fish “measures” the distortion of the electric field and infers an image of its surroundings. Understanding and implementing this bio-inspired sense offers the opportunity to enhance the navigation abilities of our underwater robots in c...
Quality Measurement: The Indispensable Bridge between Theory and Reality (No Measurements? No Science! Joint Conference - 1996: IEEE Instrumentation and Measurement Technology Conference and IMEKO Technical Committee 7. Conference Proceedings
A low-cost non-contact displacement sensor using the self-mixing effect inside a cw single-mode l... more A low-cost non-contact displacement sensor using the self-mixing effect inside a cw single-mode laser diode has been developed to measure displacements of a metallic target for modal analysis. The resonance frequencies of a thin clamped plate have been detected with an accuracy of 0.2 Hz
The International Journal of Robotics Research, 2015
In underwater robotics, several homing and docking techniques are currently being investigated. T... more In underwater robotics, several homing and docking techniques are currently being investigated. They aim to facilitate the recovery of underwater vehicles, as well as their connection to underwater stations for battery charging and data exchange. Developing reliable underwater docking strategies is a critical issue especially in murky water and/or in confined and cluttered environments. Commonly used underwater sensors such as sonar and camera can fail under these conditions. We show how a bio-inspired sensor could be used to help guide an underwater robot during a docking phase. The sensor is inspired by the passive electro-location ability of electric fish. Exploiting the electric interactions and the morphology of the vehicle, a sensor-based reactive control law is proposed. It allows the guidance of the robot toward the docking station by following an exogenous electric field generated by a set of electrodes fixed to the environment. This is achieved while avoiding insulating pe...
This article presents the first results of a work which aims at designing an active sensor inspir... more This article presents the first results of a work which aims at designing an active sensor inspired by the electric fish. Its interest is its potential for robotics underwater navigation and exploration tasks in conditions where vision and sonar would meet difficulty. It could also be used as a complementary omnidirectional, short range sense to vision and sonar. Combined with a well defined engine geometry, this sensor can be modeled analytically. In this article, we focus on a particular measurement mode where one electrode of the sensor acts as a current emitter and the others as current receivers. In spite of the high sensitivity required by electric sense, the first results show that we can obtain a detection range of the order of the sensor length, which suggests that this sensor principle could be used in future for robotics obstacle avoidance.
In this study, the electric sense is used for several modules evolving in formation. The objectiv... more In this study, the electric sense is used for several modules evolving in formation. The objective is to constitute a formation with a given shape and/or to maintain this formation. It is possible to address these problems without explicit electro-location, i.e. without determination of the relative situation (position and orientation) between the agents. The idea is to directly control the formation (i.e. the relative situation ...) in the measurements space via a sensor based control approach. A methodology to define the control law based on experimental measurements and not on a model of electric sense will be developed and experimental results are presented.
2012 IEEE International Conference on Robotics and Automation, 2012
ABSTRACT Morphology, perception and locomotion are three key features highly inter-dependent in r... more ABSTRACT Morphology, perception and locomotion are three key features highly inter-dependent in robotics. This paper gives an overview of an underwater modular robotic platform equipped with a bio-inspired electric sense. The platform is reconfigurable in the sense that it can split into independent rigid modules and vice-versa. Composed of 9 modules, the longer entity can swim like an eel over long distances, while once detached, each of its modules is efficient for small displacements with a high accuracy. Challenges are to mechanically ensure the morphology changes and to do it automatically. Electric sense is used to guide the modules during docking phases and to navigate in unknown scenes. Several aspects of the design of the robot are described and a particular attention is paid to the inter-module docking system. The feasibility of the design is assessed through experiments.
2010 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2010
The aim of this paper is to perform the navigation of an underwater robot equipped with a sensor ... more The aim of this paper is to perform the navigation of an underwater robot equipped with a sensor using the electric sense. The robot navigates in an unbounded environment in presence of spheres. This sensor is inspired of some species of electric fish. A model of this sensor composed of n spherical electrodes is established. The variations of the current due to the presence of the sphere is related to the model of Rasnow [3]. Unscented Kalman Filter is used to localize the robot with respect to the sphere and to estimate the size of the sphere. We show that bio-inspired motions improve the detection of the spheres. We illustrate the efficiency of the method in two cases: a two electrodes sensor and a four electrodes sensor.
The International Journal of Robotics Research, 2013
Electric fish sense the perturbations of a self-generated electric field through their electro-re... more Electric fish sense the perturbations of a self-generated electric field through their electro-receptive skin. This sense allows them to navigate and reconstruct their environment in conditions where vision and sonar cannot work. In this article, we use a sensor inspired by this sense to address both problems of locating and estimating the size of small objects (electrolocation) and navigating in a tank. Based on a Kalman filter, any small object in the surroundings of the motion-controlled sensor can be modeled as an equivalent sphere whose location is well estimated by the filter. As a first application to the problem of navigation, the filter is included into a closed feedback loop in order to achieve wall following in a tank. Our experimental results demonstrate the feasibility of this approach.
IEEE Transactions on Robotics, 2014
ABSTRACT Some fish species use electric sense to navigate efficiently in the turbid waters of con... more ABSTRACT Some fish species use electric sense to navigate efficiently in the turbid waters of confined spaces. This paper presents a first attempt to use this sense to control a group of nonholonomic rigid underwater vehicles navigating in a cooperative way. A leader whose motion is unknown to the others serves as an active agent for its passive neighbor, which perceives the leader’s electric field via current measurements and moves in order to follow a trajectory relative to it. Then, this passive agent, becomes in its turn the leader for the next agent and so on. Sufficient conditions of convergence of the control law are derived for electric current servoing. This is achieved without the explicit knowledge of the location of the agents. Some limits on the possible motion of the leader along with the importance of the choice of controlled outputs are demonstrated. Switching between different group configurations by following a virtual agent is also described. Simulation and experimental results illustrate the theoretical study.
IEEE Sensors Journal, 2013
ABSTRACT This article presents the first research into designing an active sensor inspired by ele... more ABSTRACT This article presents the first research into designing an active sensor inspired by electric fish. It is notable for its potential for robotics underwater navigation and exploration tasks in conditions where vision and sonar would meet difficulty. It could also be used as a complementary omnidirectional, short range sense to vision and sonar. Combined with a well defined engine geometry, this sensor can be modeled analytically. In this article, we focus on a particular measurement mode where one electrode of the sensor acts as a current emitter and the others as current receivers. In spite of the high sensitivity required by electric sense, the first results show that we can obtain a detection range of the order of the sensor length, which suggests that this sensor principle can be used for robotics obstacle avoidance as it is illustrated at the end of the article.
2008 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2008
In this paper, a multi-variable feedback design for the 3D movement of an eel-like robot is prese... more In this paper, a multi-variable feedback design for the 3D movement of an eel-like robot is presented. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the eel's head as well as the stabilization of the rolling angle. The control design is based on a recently developed reduced model that have been validated using a 3D complete continuous model described in [3]. Several scenarios are proposed to assess the efficiency of the proposed feedback law.
IEEE Transactions on Robotics, 2012
This article reports the first results from a programme of work aimed at developing a swimming ro... more This article reports the first results from a programme of work aimed at developing a swimming robot equipped with electric sense. After having presented the principles of a bioinspired electric sensor, now working, we will build the models for electrolocation of objects that are suited to this kind of sensor. The produced models are in a compact analytical form in order to be tractable on the onboard computers of the future robot. These models are tested by comparing them with numerical simulations based on the boundary elements method. The results demonstrate the feasibility of the approach and its compatibility with online objects electrolocation, another parallel programme of ours.
Journal of Computational and Nonlinear Dynamics, 2011
In this article, the finite element simulation of cables is investigated for future applications ... more In this article, the finite element simulation of cables is investigated for future applications to robotics and hydrodynamics. The solution is based on the geometrically exact approach of Cosserat beams in finite transformations, as initiated by Simo in the 1980s. However, the internal basic kinematics of the beam theory is not those of Reissner–Timoshenko but rather those of Kirchhoff. Based on these kinematics, the dynamic model adopted is a nonlinear extension of the so-called linear model of twisted and stretched Euler–Bernoulli beams. In agreement with the investigated applications, one or both of the ends of the cable are submitted to predefined motions. This model is also implemented into a computational fluid dynamics code, which solves the Reynolds-averaged Navier–Stokes equations. Regarding this last point, an implicit/iterative algorithm including a conservative load transfer for the variable hydrodynamic forces exerted all along the beam length has been used to reach a stable coupling. The relevance of the approach is tested through three advanced examples. The first is related to the prediction of cable motion in robotics. Then, the two last illustrations deal with fluid-structure interaction (FSI). A 2D classical benchmark in FSI is first investigated, and, at last, a computation illustrates the procedure in a 3D case.
Conference: 19ème Congrès Français de Mécanique [CFM2009], Marseille, France, Aug 24, 2009
Cet article présente le couplage du solveur fluide ISIS-CFD du LMF et d’un solveur structure de t... more Cet article présente le couplage du solveur fluide ISIS-CFD du LMF et d’un solveur structure de type poutre appliqué à des problèmes 3D complexes d’interaction fluide-structure des corps élancés en grand déplacement, comme les risers. Le couplage temporel s’appuie sur un algorithme itératif. Un soin tout particulier a été porté au couplage spatial, en particulier au processus de déformation de maillage. Afin de valider le code IFS, le cas-test 2D d’Hübner a été traité.
In this paper the coupling of a structural solver for elongated structures in large displacements with the flow solver ISIS-CFD is presented. ISIS-CFD is a 3-D finite volume solver based on the incompressible unsteady Reynolds-averaged Navier-Stokes equations, developed by the CFD group of the Fluid Mechanics Laboratory. The finite element structural solver uses Euler-Bernoulli or Rayleigh kinematics with the Cosserat hypothesis. The time coupling uses an iterative algorithm. Special attention to the space coupling, in particular the remeshing procedure. This coupling algorithm is first validated and then applied to the 2-D Hübner test case.
This paper presents a reduced mean model of a three-dimensional Eel-like robot. Such a robot is u... more This paper presents a reduced mean model of a three-dimensional Eel-like robot. Such a robot is under construction in the context of a national French robotic project. This model is based on mechanical considerations as well as on our experience with an existing 3D continuous model of the target prototype. Identification and validation of the dynamic model are presented here.
Procedia CIRP, 2018
The piping inspection for security or sealing checking is an important challenge when the interna... more The piping inspection for security or sealing checking is an important challenge when the internal diameter of the pipe is small with respect to its length. Some mechanisms using closed loops are able to generate contact forces and deployable structures. By using bio-inspired design, we present a mechanism which is able to move inside pipes by mimicking the motion of a caterpillar. The mechanism is composed of three sections, one for the motion and two with legs that are attached with the inner part of the pipe. A compliant mechanism is proposed to add mobility between the three sections of the robot in order to cross the singularity of the pipe. The results coming from a multi-objective optimization process is used to set the geometric and kinematic parameters of the mechanism taking into account the environmental and design constraints. A mechatronic system is proposed that uses industrial components namely DC motors, ball-screws and servo controllers which can be inserted in the pipe. For horizontal and vertical motions, the contact forces and the motor torques are computed to check the feasibility of the clamping. A prototype made at Laboratoire des Sciences du Numérique de Nantes (LS2N) is used to show the behavior of this concept for slow motions.
Techniques De L Ingenieur Informatique Industrielle, 2006
The International Journal of Robotics Research, 2020
This article exploits a bio-inspired sensor technology named artificial electric-sense to emulate... more This article exploits a bio-inspired sensor technology named artificial electric-sense to emulate underwater pre-touch. The sensor is considered as an electric finger controlled remotely by an operator to follow the boundaries of objects. Using electric measurements only, the approach feeds back pre-touch forces and torques to the operator through an haptic interface. These forces and torques are generated by a set of virtual electric charges and dipoles arranged on the probe and reacting in the electric field reflected by the objects. This model of emulated forces is passive and guarantees the stability of a position–position haptic feedback loop. The whole approach is assessed through a set of experiments carried out on a Cartesian slave robot coupled to an haptic interface. The obtained results show the feasibility of the concept and its robustness to different configurations of objects. Such an electro-haptic feedback opens new perspectives in both electric field sensing and und...
Oxford Scholarship Online, 2018
Underwater navigation in turbid water for exploration in catastrophic conditions or navigation in... more Underwater navigation in turbid water for exploration in catastrophic conditions or navigation in confined unstructured environments is still a challenge for robotics. In these conditions, neither vision nor sonar can be used. Pursuing a bio-inspired approach in robotics, one can seek solutions in nature to solve this difficult problem. Several hundred fish species in families Gymnotidae and Mormyridae have developed an original sense well adapted to this situation: the electric sense. Gnathonemus petersii first polarizes its body with respect to an electric organ discharge located at the base of its tail and generates a dipolar electric field in its near surroundings. Then, using many transcutaneous electro-receptors distributed along its body, the fish “measures” the distortion of the electric field and infers an image of its surroundings. Understanding and implementing this bio-inspired sense offers the opportunity to enhance the navigation abilities of our underwater robots in c...
Quality Measurement: The Indispensable Bridge between Theory and Reality (No Measurements? No Science! Joint Conference - 1996: IEEE Instrumentation and Measurement Technology Conference and IMEKO Technical Committee 7. Conference Proceedings
A low-cost non-contact displacement sensor using the self-mixing effect inside a cw single-mode l... more A low-cost non-contact displacement sensor using the self-mixing effect inside a cw single-mode laser diode has been developed to measure displacements of a metallic target for modal analysis. The resonance frequencies of a thin clamped plate have been detected with an accuracy of 0.2 Hz
The International Journal of Robotics Research, 2015
In underwater robotics, several homing and docking techniques are currently being investigated. T... more In underwater robotics, several homing and docking techniques are currently being investigated. They aim to facilitate the recovery of underwater vehicles, as well as their connection to underwater stations for battery charging and data exchange. Developing reliable underwater docking strategies is a critical issue especially in murky water and/or in confined and cluttered environments. Commonly used underwater sensors such as sonar and camera can fail under these conditions. We show how a bio-inspired sensor could be used to help guide an underwater robot during a docking phase. The sensor is inspired by the passive electro-location ability of electric fish. Exploiting the electric interactions and the morphology of the vehicle, a sensor-based reactive control law is proposed. It allows the guidance of the robot toward the docking station by following an exogenous electric field generated by a set of electrodes fixed to the environment. This is achieved while avoiding insulating pe...
This article presents the first results of a work which aims at designing an active sensor inspir... more This article presents the first results of a work which aims at designing an active sensor inspired by the electric fish. Its interest is its potential for robotics underwater navigation and exploration tasks in conditions where vision and sonar would meet difficulty. It could also be used as a complementary omnidirectional, short range sense to vision and sonar. Combined with a well defined engine geometry, this sensor can be modeled analytically. In this article, we focus on a particular measurement mode where one electrode of the sensor acts as a current emitter and the others as current receivers. In spite of the high sensitivity required by electric sense, the first results show that we can obtain a detection range of the order of the sensor length, which suggests that this sensor principle could be used in future for robotics obstacle avoidance.
In this study, the electric sense is used for several modules evolving in formation. The objectiv... more In this study, the electric sense is used for several modules evolving in formation. The objective is to constitute a formation with a given shape and/or to maintain this formation. It is possible to address these problems without explicit electro-location, i.e. without determination of the relative situation (position and orientation) between the agents. The idea is to directly control the formation (i.e. the relative situation ...) in the measurements space via a sensor based control approach. A methodology to define the control law based on experimental measurements and not on a model of electric sense will be developed and experimental results are presented.
2012 IEEE International Conference on Robotics and Automation, 2012
ABSTRACT Morphology, perception and locomotion are three key features highly inter-dependent in r... more ABSTRACT Morphology, perception and locomotion are three key features highly inter-dependent in robotics. This paper gives an overview of an underwater modular robotic platform equipped with a bio-inspired electric sense. The platform is reconfigurable in the sense that it can split into independent rigid modules and vice-versa. Composed of 9 modules, the longer entity can swim like an eel over long distances, while once detached, each of its modules is efficient for small displacements with a high accuracy. Challenges are to mechanically ensure the morphology changes and to do it automatically. Electric sense is used to guide the modules during docking phases and to navigate in unknown scenes. Several aspects of the design of the robot are described and a particular attention is paid to the inter-module docking system. The feasibility of the design is assessed through experiments.
2010 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2010
The aim of this paper is to perform the navigation of an underwater robot equipped with a sensor ... more The aim of this paper is to perform the navigation of an underwater robot equipped with a sensor using the electric sense. The robot navigates in an unbounded environment in presence of spheres. This sensor is inspired of some species of electric fish. A model of this sensor composed of n spherical electrodes is established. The variations of the current due to the presence of the sphere is related to the model of Rasnow [3]. Unscented Kalman Filter is used to localize the robot with respect to the sphere and to estimate the size of the sphere. We show that bio-inspired motions improve the detection of the spheres. We illustrate the efficiency of the method in two cases: a two electrodes sensor and a four electrodes sensor.
The International Journal of Robotics Research, 2013
Electric fish sense the perturbations of a self-generated electric field through their electro-re... more Electric fish sense the perturbations of a self-generated electric field through their electro-receptive skin. This sense allows them to navigate and reconstruct their environment in conditions where vision and sonar cannot work. In this article, we use a sensor inspired by this sense to address both problems of locating and estimating the size of small objects (electrolocation) and navigating in a tank. Based on a Kalman filter, any small object in the surroundings of the motion-controlled sensor can be modeled as an equivalent sphere whose location is well estimated by the filter. As a first application to the problem of navigation, the filter is included into a closed feedback loop in order to achieve wall following in a tank. Our experimental results demonstrate the feasibility of this approach.
IEEE Transactions on Robotics, 2014
ABSTRACT Some fish species use electric sense to navigate efficiently in the turbid waters of con... more ABSTRACT Some fish species use electric sense to navigate efficiently in the turbid waters of confined spaces. This paper presents a first attempt to use this sense to control a group of nonholonomic rigid underwater vehicles navigating in a cooperative way. A leader whose motion is unknown to the others serves as an active agent for its passive neighbor, which perceives the leader’s electric field via current measurements and moves in order to follow a trajectory relative to it. Then, this passive agent, becomes in its turn the leader for the next agent and so on. Sufficient conditions of convergence of the control law are derived for electric current servoing. This is achieved without the explicit knowledge of the location of the agents. Some limits on the possible motion of the leader along with the importance of the choice of controlled outputs are demonstrated. Switching between different group configurations by following a virtual agent is also described. Simulation and experimental results illustrate the theoretical study.
IEEE Sensors Journal, 2013
ABSTRACT This article presents the first research into designing an active sensor inspired by ele... more ABSTRACT This article presents the first research into designing an active sensor inspired by electric fish. It is notable for its potential for robotics underwater navigation and exploration tasks in conditions where vision and sonar would meet difficulty. It could also be used as a complementary omnidirectional, short range sense to vision and sonar. Combined with a well defined engine geometry, this sensor can be modeled analytically. In this article, we focus on a particular measurement mode where one electrode of the sensor acts as a current emitter and the others as current receivers. In spite of the high sensitivity required by electric sense, the first results show that we can obtain a detection range of the order of the sensor length, which suggests that this sensor principle can be used for robotics obstacle avoidance as it is illustrated at the end of the article.
2008 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2008
In this paper, a multi-variable feedback design for the 3D movement of an eel-like robot is prese... more In this paper, a multi-variable feedback design for the 3D movement of an eel-like robot is presented. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the eel's head as well as the stabilization of the rolling angle. The control design is based on a recently developed reduced model that have been validated using a 3D complete continuous model described in [3]. Several scenarios are proposed to assess the efficiency of the proposed feedback law.
IEEE Transactions on Robotics, 2012
This article reports the first results from a programme of work aimed at developing a swimming ro... more This article reports the first results from a programme of work aimed at developing a swimming robot equipped with electric sense. After having presented the principles of a bioinspired electric sensor, now working, we will build the models for electrolocation of objects that are suited to this kind of sensor. The produced models are in a compact analytical form in order to be tractable on the onboard computers of the future robot. These models are tested by comparing them with numerical simulations based on the boundary elements method. The results demonstrate the feasibility of the approach and its compatibility with online objects electrolocation, another parallel programme of ours.
Journal of Computational and Nonlinear Dynamics, 2011
In this article, the finite element simulation of cables is investigated for future applications ... more In this article, the finite element simulation of cables is investigated for future applications to robotics and hydrodynamics. The solution is based on the geometrically exact approach of Cosserat beams in finite transformations, as initiated by Simo in the 1980s. However, the internal basic kinematics of the beam theory is not those of Reissner–Timoshenko but rather those of Kirchhoff. Based on these kinematics, the dynamic model adopted is a nonlinear extension of the so-called linear model of twisted and stretched Euler–Bernoulli beams. In agreement with the investigated applications, one or both of the ends of the cable are submitted to predefined motions. This model is also implemented into a computational fluid dynamics code, which solves the Reynolds-averaged Navier–Stokes equations. Regarding this last point, an implicit/iterative algorithm including a conservative load transfer for the variable hydrodynamic forces exerted all along the beam length has been used to reach a stable coupling. The relevance of the approach is tested through three advanced examples. The first is related to the prediction of cable motion in robotics. Then, the two last illustrations deal with fluid-structure interaction (FSI). A 2D classical benchmark in FSI is first investigated, and, at last, a computation illustrates the procedure in a 3D case.
IEEE Transactions on Robotics, 2006
This paper presents the dynamic modeling of a continuous three-dimensional swimming eel-like robo... more This paper presents the dynamic modeling of a continuous three-dimensional swimming eel-like robot. The modeling approach is based on the "geometrically exact beam theory" and on that of Newton-Euler, as it is well known within the robotics community. The proposed algorithm allows us to compute the robot's Galilean movement and the control torques as a function of the expected internal deformation of the eel's body.