D. Chablat - Profile on Academia.edu (original) (raw)
Parallel robots papers by D. Chablat
Abstract This paper addresses an interval analysis based study that is applied to the design and ... more Abstract This paper addresses an interval analysis based study that is applied to the design and the comparison of three-degrees-of-freedom (3-DoF) parallel kinematic machines. Two design criteria are used:(i) a regular workspace shape and (ii) a kinetostatic performance index that needs to be as homogeneous as possible throughout the workspace.
Papers by D. Chablat
Workspaces Classification of 3R Orthogonal Manipulators
On Advances in Robot Kinematics, 2004
A classification of a family of 3-revolute (3R) positioning manipulators is established. This cla... more A classification of a family of 3-revolute (3R) positioning manipulators is established. This classification is based on the topology of their workspace. The workspace is characterized in a half-cross section by the singular curves of the manipulator. The workspace topology is defined by the number of cusps and nodes that appear on these singular curves. The design parameters space is shown to be partitioned into nine subspaces of distinct workspace topologies. Each separating surface is given as an explicit expression in the DH-parameters.
Volume 10: 44th Mechanisms and Robotics Conference (MR), 2020
The paper deals with the stiffness analysis and stability study of equilibrium configurations for... more The paper deals with the stiffness analysis and stability study of equilibrium configurations for dual-triangle tensegrity mechanism, which is actuated by adjusting elastic connections between the triangle edges. For this mechanism, the torque-deflection relation was obtained as a function of control inputs and geometric parameters. It was proved that the mechanism can has either a single or three equilibrium configurations that can be both stable and unstable. Corresponding conditions of stability were found allowing user to choose control inputs ensuring the mechanism controllability. The obtained results are confirmed by the simulation examples presented in the paper.
Proceedings of the Third International Conference on Informatics in Control, Automation and Robotics, 2006
The subject of this paper is about the kinematic analysis and the trajectory planning of the Orth... more The subject of this paper is about the kinematic analysis and the trajectory planning of the Orthoglide 5-axis. The Orthoglide 5-axis a five degrees of freedom parallel kinematic machine developed at IRCCyN and is made up of a hybrid architecture, namely, a three degrees of freedom translational parallel manipulator mounted in series with a two degrees of freedom parallel spherical wrist. The simpler the kinematic modeling of the Orthoglide 5-axis, the higher the maximum frequency of its control loop. Indeed, the control loop of a parallel kinematic machine should be computed with a high frequency, i.e., higher than 1.5 MHz, in order the manipulator to be able to reach high speed motions with a good accuracy. Accordingly, the direct and inverse kinematic models of the Orthoglide 5-axis, its inverse kinematic Jacobian matrix and the first derivative of the latter with respect to time are expressed in this paper. It appears that the kinematic model of the manipulator under study can be written in a quadratic form due to the hybrid architecture of the Orthoglide 5-axis. As illustrative examples, the profiles of the actuated joint angles (lengths), velocities and accelerations that are used in the control loop of the robot are traced for two test trajectories.
The orthoglide is a 3-DOF parallel mechanism designed at IRCCyN for machining applications. It fe... more The orthoglide is a 3-DOF parallel mechanism designed at IRCCyN for machining applications. It features three fixed parallel linear joints which are mounted orthogonally and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The orthoglide has been designed as function of a prescribed Cartesian workspace with prescribed kinetostatic performances. The interesting features of the orthoglide are a regular Cartesian workspace shape, uniform performances in all directions and good compactness. A small-scale prototype of the orthoglide under development is presented at the end of this paper.
Volume 5A: 42nd Mechanisms and Robotics Conference, 2018
In robotic rehabilitation the interaction is usually implemented by means of robots based on mult... more In robotic rehabilitation the interaction is usually implemented by means of robots based on multi-Degree of Freedom (DOF) open kinematic chains. Despite their inherent flexibility these machines are expensive, complex and require routine maintenance and IT support. In contrast, mechanisms based on closed kinematic chains and especially 1-DOF four- and six bar linkages are simple, yet capable of generating paths with complex kinematic characteristics. These mechanisms are preferable when simplicity and cost are the major criteria, for example in the case of community-based rehabilitation in developing countries. On the other hand, rehabilitation using 1-DOF limits flexibility and potentially impairs the exercise effectiveness, since the patient does not have access to a variety of kinematic challenges. Nevertheless, by careful ergonomic design and by considering varying time constraints, link rotation ranges and varying link lengths this limitation can be overcome. This work aims to...
Journal of Mechanisms and Robotics, 2019
This article presents a new variable actuation mechanism based on the 3-RPR parallel robot. This ... more This article presents a new variable actuation mechanism based on the 3-RPR parallel robot. This mechanism is an evolution of the NaVARo robot, a 3-RRR parallel robot, for which the second revolute joint of the three legs is replaced by a scissor to obtain a larger working space and avoid the use of parallelograms to operate the second revolute joint. To obtain better spatial rigidity, the leg mechanism is constructed by placing the scissors in an orthogonal plane to the plane of the manipulator displacement (3-RRR or even the 3-RPR). This geometric property brings the significant consequence of allowing the scissors to directly substitute the prismatic chains in the 3-RPR and enjoy the same kinematics advantages for the overall robots as only one solution to the inverse kinematic model. From the Jacobian expression, surfaces of singularity can be calculated and presented in a compact form. The singularity equations are presented for a robot with a similar base and mobile platform. ...
Éco-conception et innovation responsable, 2015
L'objectif de ce projet soutenu par le programme ROBEA CNRS est de concevoir, étudier et réaliser... more L'objectif de ce projet soutenu par le programme ROBEA CNRS est de concevoir, étudier et réaliser un robot « anguille » capable de nager en trois dimensions. Pour cela nous étudions sur la base de modèles continus macroscopiques, les problèmes de la simulation, locomotion et commande. L'étude s'appuie sur une analyse biomécanique de la nage et se concrétise par la réalisation d'une plate-forme logicielle et d'un prototype. Pour atteindre ces objectifs un groupe pluridisciplinaire d'équipes et laboratoires a été formé :
Optimal Design of the Three-Degree-of-Freedom Parallel Manipulator in a Spray-Painting Equipment
Robotica, 2019
SUMMARYSpray-painting equipments are important for the automatic spraying of long conical objects... more SUMMARYSpray-painting equipments are important for the automatic spraying of long conical objects such as rocket fairing. This paper proposes a spray-painting equipment that consists of a feed worktable, a gantry frame and two serial–parallel mechanisms and investigates the optimal design of PRR–PRR parallel manipulator in serial–parallel mechanisms. Based on the kinematic model of the parallel manipulator, the conditioning performance, workspace and accuracy performance indices are defined. The dynamic model is derived using virtual work principle and dynamic evaluation index is defined. The conditioning performance, workspace, accuracy performance and dynamic performance are involved in multi-objective optimization design to determine the optimal geometrical parameters of the parallel manipulator. Furthermore, the geometrical parameters of the gantry frame are optimized. An example is given to show how to determine these parameters by taking a long object with conical surface as p...
Various performance indices are used for the design of serial manipulators. One method of optimiz... more Various performance indices are used for the design of serial manipulators. One method of optimization relies on the condition number of the Jacobian matrix. The minimization of the condition number leads, under certain conditions, to isotropic configurations, for which the roundoff-error amplification is lowest. In this paper, the isotropy conditions, introduced elsewhere, are the motivation behind the introduction of isotropic sets of points. By connecting together these points, we define families of isotropic manipulators. This paper is devoted to planar manipulators, the concepts being currently extended to their spatial counterparts. Furthermore, only manipulators with revolute joints are considered here.
Proceedings of the ASME Design Engineering Technical Conference, 2008
The kinematic analysis of a spherical wrist with parallel architecture is the object of this arti... more The kinematic analysis of a spherical wrist with parallel architecture is the object of this article. This study is part of a larger French project, which aims to design and to build an eel like robot to imitate the eel swimming. To implement direct and inverse kinematics on the control law of the prototype, we need to evaluate the workspace without any collisions between the different bodies. The tilt and torsion parameters are used to represent the workspace.
Communications in Computer and Information Science, 2011
International Journal of Industrial Ergonomics, 2011
Virtual reality techniques have been increasingly used for ergonomic applications. However, it is... more Virtual reality techniques have been increasingly used for ergonomic applications. However, it is always important to know whether the results obtained in a virtual environment (VE) are representative of a real environment (RE) ones. This paper presents our preliminary experimental results on the relationship between ergonomic measurements in VE and RE for some typical "drilling" tasks. The same tasks were carried out by thirty male manufacturing factory workers in both VE and RE. Five evaluation indices e three objective (elbow angle, maximum force capacity reduction, and task completion time) and two subjective (BPD e Body Part Discomfort and RPE e Rated Perceived Exertion) e were used to evaluate the similarities between VE and RE for the selected "drilling" tasks. Four of these indices (all except elbow angle) were significantly higher (p < 0.05) in VE than in RE, which indicates that subjects experienced more discomfort and grew fatigued more quickly in VE. However, linear correlations (Pearson's rho: 0.635e0.807) between VE and RE were found for two of the five indices (BPD and maximum force capacity reduction). Relevance to industry: Using digital mock-ups and virtual reality simulations, industrial work activities can be evaluated to identify potential ergonomic problems during an early design stage, which reduces design time and costs, increases quality and improves customer satisfaction. A validated linear relationship can provide a reference for work design in virtual reality.
The work presented in this paper is related to the use of a haptic device in an environment of ro... more The work presented in this paper is related to the use of a haptic device in an environment of robotic simulation. Such device introduces a new approach to feel and to understand the boundaries of the workspace of mechanisms as well as its kinetostatic properties. Indeed, these concepts are abstract and thus often difficult to understand for the end-users. To catch his attention, we propose to amplify the problems of the mechanisms in order to help him to take the good decisions.
Sébastien Briot
... Philippe Wenger Institut de Recherche en Communications et Cybernétique de Nantes 1, rue la N... more ... Philippe Wenger Institut de Recherche en Communications et Cybernétique de Nantes 1, rue la Noë BP 92101 44321, Nantes Cedex 3, France Self-Motions of General 3-RPR Planar Parallel Robots Abstract We study ...
Computers & Industrial Engineering, 2009
Automation technique has been widely used in manufacturing industry, but there are still manual h... more Automation technique has been widely used in manufacturing industry, but there are still manual handling operations required in assembly and maintenance work in industry. Inappropriate posture and physical fatigue might result in musculoskeletal disorders (MSDs) in such physical jobs. In ergonomics and occupational biomechanics, virtual human modelling techniques have been employed to design and optimize the manual operations in design stage so as to avoid or decrease potential MSD risks. In these methods, physical fatigue is only considered as minimizing the muscle or joint stress, and the fatigue effect along time for the posture is not considered enough. In this study, based on the existing methods and multiple objective optimisation method (MOO), a new posture prediction and analysis method is proposed for predicting the optimal posture and evaluating the physical fatigue in the manual handling operation. The posture prediction and analysis problem is mathematically described and a special application case is demonstrated for analyzing a drilling assembly operation in European Aeronautic Defence & Space Company (EADS) in this paper.
Abstract This paper addresses an interval analysis based study that is applied to the design and ... more Abstract This paper addresses an interval analysis based study that is applied to the design and the comparison of three-degrees-of-freedom (3-DoF) parallel kinematic machines. Two design criteria are used:(i) a regular workspace shape and (ii) a kinetostatic performance index that needs to be as homogeneous as possible throughout the workspace.
Workspaces Classification of 3R Orthogonal Manipulators
On Advances in Robot Kinematics, 2004
A classification of a family of 3-revolute (3R) positioning manipulators is established. This cla... more A classification of a family of 3-revolute (3R) positioning manipulators is established. This classification is based on the topology of their workspace. The workspace is characterized in a half-cross section by the singular curves of the manipulator. The workspace topology is defined by the number of cusps and nodes that appear on these singular curves. The design parameters space is shown to be partitioned into nine subspaces of distinct workspace topologies. Each separating surface is given as an explicit expression in the DH-parameters.
Volume 10: 44th Mechanisms and Robotics Conference (MR), 2020
The paper deals with the stiffness analysis and stability study of equilibrium configurations for... more The paper deals with the stiffness analysis and stability study of equilibrium configurations for dual-triangle tensegrity mechanism, which is actuated by adjusting elastic connections between the triangle edges. For this mechanism, the torque-deflection relation was obtained as a function of control inputs and geometric parameters. It was proved that the mechanism can has either a single or three equilibrium configurations that can be both stable and unstable. Corresponding conditions of stability were found allowing user to choose control inputs ensuring the mechanism controllability. The obtained results are confirmed by the simulation examples presented in the paper.
Proceedings of the Third International Conference on Informatics in Control, Automation and Robotics, 2006
The subject of this paper is about the kinematic analysis and the trajectory planning of the Orth... more The subject of this paper is about the kinematic analysis and the trajectory planning of the Orthoglide 5-axis. The Orthoglide 5-axis a five degrees of freedom parallel kinematic machine developed at IRCCyN and is made up of a hybrid architecture, namely, a three degrees of freedom translational parallel manipulator mounted in series with a two degrees of freedom parallel spherical wrist. The simpler the kinematic modeling of the Orthoglide 5-axis, the higher the maximum frequency of its control loop. Indeed, the control loop of a parallel kinematic machine should be computed with a high frequency, i.e., higher than 1.5 MHz, in order the manipulator to be able to reach high speed motions with a good accuracy. Accordingly, the direct and inverse kinematic models of the Orthoglide 5-axis, its inverse kinematic Jacobian matrix and the first derivative of the latter with respect to time are expressed in this paper. It appears that the kinematic model of the manipulator under study can be written in a quadratic form due to the hybrid architecture of the Orthoglide 5-axis. As illustrative examples, the profiles of the actuated joint angles (lengths), velocities and accelerations that are used in the control loop of the robot are traced for two test trajectories.
The orthoglide is a 3-DOF parallel mechanism designed at IRCCyN for machining applications. It fe... more The orthoglide is a 3-DOF parallel mechanism designed at IRCCyN for machining applications. It features three fixed parallel linear joints which are mounted orthogonally and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The orthoglide has been designed as function of a prescribed Cartesian workspace with prescribed kinetostatic performances. The interesting features of the orthoglide are a regular Cartesian workspace shape, uniform performances in all directions and good compactness. A small-scale prototype of the orthoglide under development is presented at the end of this paper.
Volume 5A: 42nd Mechanisms and Robotics Conference, 2018
In robotic rehabilitation the interaction is usually implemented by means of robots based on mult... more In robotic rehabilitation the interaction is usually implemented by means of robots based on multi-Degree of Freedom (DOF) open kinematic chains. Despite their inherent flexibility these machines are expensive, complex and require routine maintenance and IT support. In contrast, mechanisms based on closed kinematic chains and especially 1-DOF four- and six bar linkages are simple, yet capable of generating paths with complex kinematic characteristics. These mechanisms are preferable when simplicity and cost are the major criteria, for example in the case of community-based rehabilitation in developing countries. On the other hand, rehabilitation using 1-DOF limits flexibility and potentially impairs the exercise effectiveness, since the patient does not have access to a variety of kinematic challenges. Nevertheless, by careful ergonomic design and by considering varying time constraints, link rotation ranges and varying link lengths this limitation can be overcome. This work aims to...
Journal of Mechanisms and Robotics, 2019
This article presents a new variable actuation mechanism based on the 3-RPR parallel robot. This ... more This article presents a new variable actuation mechanism based on the 3-RPR parallel robot. This mechanism is an evolution of the NaVARo robot, a 3-RRR parallel robot, for which the second revolute joint of the three legs is replaced by a scissor to obtain a larger working space and avoid the use of parallelograms to operate the second revolute joint. To obtain better spatial rigidity, the leg mechanism is constructed by placing the scissors in an orthogonal plane to the plane of the manipulator displacement (3-RRR or even the 3-RPR). This geometric property brings the significant consequence of allowing the scissors to directly substitute the prismatic chains in the 3-RPR and enjoy the same kinematics advantages for the overall robots as only one solution to the inverse kinematic model. From the Jacobian expression, surfaces of singularity can be calculated and presented in a compact form. The singularity equations are presented for a robot with a similar base and mobile platform. ...
Éco-conception et innovation responsable, 2015
L'objectif de ce projet soutenu par le programme ROBEA CNRS est de concevoir, étudier et réaliser... more L'objectif de ce projet soutenu par le programme ROBEA CNRS est de concevoir, étudier et réaliser un robot « anguille » capable de nager en trois dimensions. Pour cela nous étudions sur la base de modèles continus macroscopiques, les problèmes de la simulation, locomotion et commande. L'étude s'appuie sur une analyse biomécanique de la nage et se concrétise par la réalisation d'une plate-forme logicielle et d'un prototype. Pour atteindre ces objectifs un groupe pluridisciplinaire d'équipes et laboratoires a été formé :
Optimal Design of the Three-Degree-of-Freedom Parallel Manipulator in a Spray-Painting Equipment
Robotica, 2019
SUMMARYSpray-painting equipments are important for the automatic spraying of long conical objects... more SUMMARYSpray-painting equipments are important for the automatic spraying of long conical objects such as rocket fairing. This paper proposes a spray-painting equipment that consists of a feed worktable, a gantry frame and two serial–parallel mechanisms and investigates the optimal design of PRR–PRR parallel manipulator in serial–parallel mechanisms. Based on the kinematic model of the parallel manipulator, the conditioning performance, workspace and accuracy performance indices are defined. The dynamic model is derived using virtual work principle and dynamic evaluation index is defined. The conditioning performance, workspace, accuracy performance and dynamic performance are involved in multi-objective optimization design to determine the optimal geometrical parameters of the parallel manipulator. Furthermore, the geometrical parameters of the gantry frame are optimized. An example is given to show how to determine these parameters by taking a long object with conical surface as p...
Various performance indices are used for the design of serial manipulators. One method of optimiz... more Various performance indices are used for the design of serial manipulators. One method of optimization relies on the condition number of the Jacobian matrix. The minimization of the condition number leads, under certain conditions, to isotropic configurations, for which the roundoff-error amplification is lowest. In this paper, the isotropy conditions, introduced elsewhere, are the motivation behind the introduction of isotropic sets of points. By connecting together these points, we define families of isotropic manipulators. This paper is devoted to planar manipulators, the concepts being currently extended to their spatial counterparts. Furthermore, only manipulators with revolute joints are considered here.
Proceedings of the ASME Design Engineering Technical Conference, 2008
The kinematic analysis of a spherical wrist with parallel architecture is the object of this arti... more The kinematic analysis of a spherical wrist with parallel architecture is the object of this article. This study is part of a larger French project, which aims to design and to build an eel like robot to imitate the eel swimming. To implement direct and inverse kinematics on the control law of the prototype, we need to evaluate the workspace without any collisions between the different bodies. The tilt and torsion parameters are used to represent the workspace.
Communications in Computer and Information Science, 2011
International Journal of Industrial Ergonomics, 2011
Virtual reality techniques have been increasingly used for ergonomic applications. However, it is... more Virtual reality techniques have been increasingly used for ergonomic applications. However, it is always important to know whether the results obtained in a virtual environment (VE) are representative of a real environment (RE) ones. This paper presents our preliminary experimental results on the relationship between ergonomic measurements in VE and RE for some typical "drilling" tasks. The same tasks were carried out by thirty male manufacturing factory workers in both VE and RE. Five evaluation indices e three objective (elbow angle, maximum force capacity reduction, and task completion time) and two subjective (BPD e Body Part Discomfort and RPE e Rated Perceived Exertion) e were used to evaluate the similarities between VE and RE for the selected "drilling" tasks. Four of these indices (all except elbow angle) were significantly higher (p < 0.05) in VE than in RE, which indicates that subjects experienced more discomfort and grew fatigued more quickly in VE. However, linear correlations (Pearson's rho: 0.635e0.807) between VE and RE were found for two of the five indices (BPD and maximum force capacity reduction). Relevance to industry: Using digital mock-ups and virtual reality simulations, industrial work activities can be evaluated to identify potential ergonomic problems during an early design stage, which reduces design time and costs, increases quality and improves customer satisfaction. A validated linear relationship can provide a reference for work design in virtual reality.
The work presented in this paper is related to the use of a haptic device in an environment of ro... more The work presented in this paper is related to the use of a haptic device in an environment of robotic simulation. Such device introduces a new approach to feel and to understand the boundaries of the workspace of mechanisms as well as its kinetostatic properties. Indeed, these concepts are abstract and thus often difficult to understand for the end-users. To catch his attention, we propose to amplify the problems of the mechanisms in order to help him to take the good decisions.
Sébastien Briot
... Philippe Wenger Institut de Recherche en Communications et Cybernétique de Nantes 1, rue la N... more ... Philippe Wenger Institut de Recherche en Communications et Cybernétique de Nantes 1, rue la Noë BP 92101 44321, Nantes Cedex 3, France Self-Motions of General 3-RPR Planar Parallel Robots Abstract We study ...
Computers & Industrial Engineering, 2009
Automation technique has been widely used in manufacturing industry, but there are still manual h... more Automation technique has been widely used in manufacturing industry, but there are still manual handling operations required in assembly and maintenance work in industry. Inappropriate posture and physical fatigue might result in musculoskeletal disorders (MSDs) in such physical jobs. In ergonomics and occupational biomechanics, virtual human modelling techniques have been employed to design and optimize the manual operations in design stage so as to avoid or decrease potential MSD risks. In these methods, physical fatigue is only considered as minimizing the muscle or joint stress, and the fatigue effect along time for the posture is not considered enough. In this study, based on the existing methods and multiple objective optimisation method (MOO), a new posture prediction and analysis method is proposed for predicting the optimal posture and evaluating the physical fatigue in the manual handling operation. The posture prediction and analysis problem is mathematically described and a special application case is demonstrated for analyzing a drilling assembly operation in European Aeronautic Defence & Space Company (EADS) in this paper.
arXiv (Cornell University), Jun 6, 2011
Emails: {Abdel-Kader.Zaiter, Philippe.Wenger, Damien.Chablat}@irccyn.ec-nantes.fr} Résumé-Dans un... more Emails: {Abdel-Kader.Zaiter, Philippe.Wenger, Damien.Chablat}@irccyn.ec-nantes.fr} Résumé-Dans une section de l'espace articulaire des manipulateurs parallèles, les points cusps et noeuds ont un rôle essentiel dans le changement de mode d'assemblage. Ce travail présente une étude détaillée de ces points dans l'espace articulaire et de travail. On démontre qu'un point cusp (resp. un noeud) définit un point de tangence (resp. un point d'intersection), dans l'espace de travail, entre les courbes singulières et les courbes associées aux surfaces caractéristiques. L'étude est illustrée sur le manipulateur planaire 3-RPR mais son champ d'application est général.