oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 1284 matches for " Damien Chablat "
All listed articles are free for downloading (OA Articles)
Page 1 /1284
Display every page Item
Kinematic Analysis of the vertebra of an eel like robot
Damien Chablat
Physics , 2008,
Abstract: 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.
Path Planner for Objects, Robots and Mannequins by Multi-Agents Systems or Motion Captures
Damien Chablat
Computer Science , 2008,
Abstract: In order to optimise the costs and time of design of the new products while improving their quality, concurrent engineering is based on the digital model of these products. However, in order to be able to avoid definitively physical model without loss of information, new tools must be available. Especially, a tool making it possible to check simply and quickly the maintainability of complex mechanical sets using the numerical model is necessary. Since one decade, the MCM team of IRCCyN works on the creation of tools for the generation and the analysis of trajectories of virtual mannequins. The simulation of human tasks can be carried out either by robot-like simulation or by simulation by motion capture. This paper presents some results on the both two methods. The first method is based on a multi-agent system and on a digital mock-up technology, to assess an efficient path planner for a manikin or a robot for access and visibility task taking into account ergonomic constraints or joint limits. The human operator is integrated in the process optimisation to contribute to a global perception of the environment. This operator cooperates, in real-time, with several automatic local elementary agents. In the second method, we worked with the CEA and EADS/CCR to solve the constraints related to the evolution of human virtual in its environment on the basis of data resulting from motion capture system. An approach using of the virtual guides was developed to allow to the user the realization of precise trajectory in absence of force feedback.
Animation of virtual mannequins, robot-like simulation or motion captures
Damien Chablat
Computer Science , 2007,
Abstract: In order to optimize the costs and time of design of the new products while improving their quality, concurrent engineering is based on the digital model of these products, the numerical model. However, in order to be able to avoid definitively physical model, old support of the design, without loss of information, new tools must be available. Especially, a tool making it possible to check simply and quickly the maintainability of complex mechanical sets using the numerical model is necessary. Since one decade, our team works on the creation of tool for the generation and the analysis of trajectories of virtual mannequins. The simulation of human tasks can be carried out either by robot-like simulation or by simulation by motion capture. This paper presents some results on the both two methods. The first method is based on a multi-agent system and on a digital mock-up technology, to assess an efficient path planner for a manikin or a robot for access and visibility task taking into account ergonomic constraints or joint and mechanical limits. In order to solve this problem, the human operator is integrated in the process optimization to contribute to a global perception of the environment. This operator cooperates, in real-time, with several automatic local elementary agents. In the case of the second approach, we worked with the CEA and EADS/CCR to solve the constraints related to the evolution of human virtual in its environment on the basis of data resulting from motion capture system. An approach using of the virtual guides was developed to allow to the user the realization of precise trajectory in absence of force feedback. The result of this work validates solutions through the digital mock-up; it can be applied to simulate maintenability and mountability tasks.
Joint space and workspace analysis of a two-DOF closed-chain manipulator
Damien Chablat
Computer Science , 2010,
Abstract: The aim of this paper is to compute of the generalized aspects, i.e. the maximal singularity-free domains in the Cartesian product of the joint space and workspace, for a planar parallel mechanism in using quadtree model and interval analysis based method. The parallel mechanisms can admit several solutions to the inverses and the direct kinematic models. These singular configurations divide the joint space and the workspace in several not connected domains. To compute this domains, the quadtree model can be made by using a discretization of the space. Unfortunately, with this method, some singular configurations cannot be detected as a single point in the joint space. The interval analysis based method allow us to assure that no singularities are not found and to reduce the computing times. This approach is tested on a simple planar parallel mechanism with two degrees of freedom.
Kinematic analysis of a class of analytic planar 3-RPR parallel manipulators
Philippe Wenger,Damien Chablat
Computer Science , 2009,
Abstract: A class of analytic planar 3-RPR manipulators is analyzed in this paper. These manipulators have congruent base and moving platforms and the moving platform is rotated of 180 deg about an axis in the plane. The forward kinematics is reduced to the solution of a 3rd-degree polynomial and a quadratic equation in sequence. The singularities are calculated and plotted in the joint space. The second-order singularities (cups points), which play an important role in non-singular change of assembly-mode motions, are also analyzed.
A New Six Degree-of-Freedom Haptic Device based on the Orthoglide and the Agile Eye
Damien Chablat,Philippe Wenger
Computer Science , 2007,
Abstract: The aim of this paper is to present a new six degree-of-freedom (dof) haptic device using two parallel mechanisms. The first one, called orthoglide, provides the translation motions and the second one produces the rotational motions. These two motions are decoupled to simplify the direct and inverse kinematics, as it is needed for real-times control. To reduce the inertial load, the motors are fixed on the base and a transmission with two universal joints is used to transmit the rotational motions from the base to the end-effector. The main feature of the orthoglide and of the agile eye mechanism is the existence of an isotropic configuration. The length of the legs and the range limits of the orthoglide are optimized to have homogeneous performance throughout the Cartesian workspace, which has a nearly cubic workspace. These properties permit to have a high stiffness throughout the workspace and workspace limits that are easily understandable by the user.
Moveability and Collision Analysis for Fully-Parallel Manipulators
Damien Chablat,Philippe Wenger
Computer Science , 2007,
Abstract: The aim of this paper is to characterize the moveability of fully-parallel manipulators in the presence of obstacles. Fully parallel manipulators are used in applications where accuracy, stiffness or high speeds and accelerations are required \cite{Merlet:97}. However, one of its main drawbacks is a relatively small workspace compared to the one of serial manipulators. This is due mainly to the existence of potential internal collisions, and the existence of singularities. In this paper, the notion of free aspect is defined which permits to exhibit domains of the workspace and the joint space free of singularity and collision. The main application of this study is the moveability analysis in the workspace of the manipulator as well as path-planning, control and design.
Design of a Spherical Wrist with Parallel Architecture: Application to Vertebrae of an Eel Robot
Damien Chablat,Philippe Wenger
Computer Science , 2007,
Abstract: The design of a spherical wrist with parallel architecture is the object of this article. This study is part of a larger project, which aims to design and to build an eel robot for inspection of immersed piping. The kinematic analysis of the mechanism is presented first to characterize the singular configurations as well as the isotropic configurations. We add the design constraints related to the application, such as (i) the compactness of the mechanism, (ii) the symmetry of the elements in order to ensure static and dynamic balance and (iii) the possibility of the mechanism to fill the elliptic form of the ell sections.
The Computation of All 4R Serial Spherical Wrists With an Isotropic Architecture
Damien Chablat,Jorge Angeles
Computer Science , 2007,
Abstract: A spherical wrist of the serial type is said to be isotropic if it can attain a posture whereby the singular values of its Jacobian matrix are all identical and nonzero. What isotropy brings about is robustness to manufacturing, assembly, and measurement errors, thereby guaranteeing a maximum orientation accuracy. In this paper we investigate the existence of redundant isotropic architectures, which should add to the dexterity of the wrist under design by virtue of its extra degree of freedom. The problem formulation leads to a system of eight quadratic equations with eight unknowns. The Bezout number of this system is thus 2^8 = 256, its BKK bound being 192. However, the actual number of solutions is shown to be 32. We list all solutions of the foregoing algebraic problem. All these solutions are real, but distinct solutions do not necessarily lead to distinct manipulators. Upon discarding those algebraic solutions that yield no new wrists, we end up with exactly eight distinct architectures, the eight corresponding manipulators being displayed at their isotropic posture.
Kinematic Analysis of a New Parallel Machine Tool: the Orthoglide
Philippe Wenger,Damien Chablat
Computer Science , 2007,
Abstract: This paper describes a new parallel kinematic architecture for machining applications: the orthoglide. This machine 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 main interest of the orthoglide is that it takes benefit from the advantages of the popular PPP serial machines (regular Cartesian workspace shape and uniform performances) as well as from the parallel kinematic arrangement of the links (less inertia and better dynamic performances), which makes the orthoglide well suited to high-speed machining applications. Possible extension of the orthoglide to 5-axis machining is also investigated.
Page 1 /1284
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.