The Experts below are selected from a list of 2004 Experts worldwide ranked by ideXlab platform
Cadavid C. - One of the best experts on this subject based on the ideXlab platform.
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Ellipse-based principal component analysis for self-Intersecting Curve reconstruction from noisy point sets
'Springer Science and Business Media LLC', 2021Co-Authors: Ruiz O., Vanegas C., Cadavid C.Abstract:Surface reconstruction from cross cuts usually requires Curve reconstruction from planar noisy point samples. The output Curves must form a possibly disconnected 1-manifold for the surface reconstruction to proceed. This article describes an implemented algorithm for the reconstruction of planar Curves (1-manifolds) out of noisy point samples of a self-Intersecting or nearly self-Intersecting planar Curve C. C:[a,b]R?R 2 is self-Intersecting if C(u)=C(v), u v, u,v (a,b) (C(u) is the self-intersection point). We consider only transversal self-intersections, i.e. those for which the tangents of the Intersecting branches at the intersection point do not coincide (C (u)=C(v)). In the presence of noise, Curves which self-intersect cannot be distinguished from Curves which nearly self-intersect. Existing algorithms for Curve reconstruction out of either noisy point samples or pixel data, do not produce a (possibly disconnected) Piecewise Linear 1-manifold approaching the whole point sample. The algorithm implemented in this work uses Principal Component Analysis (PCA) with elliptic support regions near the self-intersections. The algorithm was successful in recovering contours out of noisy slice samples of a surface, for the Hand, Pelvis and Skull data sets. As a test for the correctness of the obtained Curves in the slice levels, they were input into an algorithm of surface reconstruction, leading to a reconstructed surface which reproduces the topological and geometrical properties of the original object. The algorithm robustly reacts not only to statistical non-correlation at the self-intersections (non-manifold neighborhoods) but also to occasional high noise at the non-self-Intersecting (1-manifold) neighborhoods. © 2010 Springer-Verlag
Xincheng Tian - One of the best experts on this subject based on the ideXlab platform.
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robot path planning with two axis positioner for non ideal sphere pipe joint welding based on laser scanning
The International Journal of Advanced Manufacturing Technology, 2019Co-Authors: Yan Liu, Xincheng TianAbstract:Our paper mainly introduces a novel path planning method for non-ideal sphere-pipe Intersecting Curve robot welding based on laser scanning. This method integrates the generation of laser scanning trajectory, the processing of scanning data, and the path planning of non-ideal sphere-pipe joint welding. First, the paper perfects the ideal sphere-pipe intersection model and represents the parametric equation of ideal Intersecting Curve, which can cover all the intersection ways for sphere-pipe joints. Since the spheres and pipes applied in actual production are not standard, this paper adopts the scheme of scanning and identifying weld seam using the laser displacement sensor and gives the laser sensor scanning trajectory by analyzing the direction and attitude of space welds. In this paper, by sampling and filtering the distance data obtained from laser sensor, a novel weld point identification algorithm suitable for the above scanning trajectory is proposed. In response to the constantly changing of sphere-pipe joints’ weld inclination and attitude, this paper adopts the robot-positioner welding scheme and introduces a novel algorithm for solving the position of two external axes. The ADAMS simulation experiments prove that this scheme can effectively avoid the adverse effects of the uphill and downhill welding on the welding quality.
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trajectory and velocity planning of the robot for sphere pipe intersection hole cutting with single y welding groove
Robotics and Computer-integrated Manufacturing, 2019Co-Authors: Yan Liu, Ya Liu, Xincheng TianAbstract:Abstract The influence of welding preparation and surface treatment of the weldment on welding quality is very important. Single Y-groove technique is a common surface treatment technique in Intersecting Curve welding. This paper presents a trajectory and velocity planning method for robot to machine a spherical single Y-groove. First, the geometrical models of the sphere-pipe intersection and the single Y-groove are established. This model can cover most of the intersection modes and parameterizes the groove angle and root face height to obtain the optimum process parameters. The above model forms the basis of robot trajectory planning and is the core innovations of this paper. Based on this model and the principle of three-dimensional tool compensation, our paper designs the interface of cutting robot tool compensation. Through this interface, the operators can flexibly change the radius to adapt to different tools or cutting torches, which can fulfill the requirements of dynamic compensation. As the goal of our paper, this method gives a general trajectory description of the robot and introduces two algorithms for the velocity planning to ensure the stability of the robot velocity. Finally, this paper takes the plasma cutting as example, and gives the relevant algorithm to solve the optimal start position and orientation of the plasma torch, which can avoid the cutting defects.
Ruiz O. - One of the best experts on this subject based on the ideXlab platform.
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Ellipse-based principal component analysis for self-Intersecting Curve reconstruction from noisy point sets
'Springer Science and Business Media LLC', 2021Co-Authors: Ruiz O., Vanegas C., Cadavid C.Abstract:Surface reconstruction from cross cuts usually requires Curve reconstruction from planar noisy point samples. The output Curves must form a possibly disconnected 1-manifold for the surface reconstruction to proceed. This article describes an implemented algorithm for the reconstruction of planar Curves (1-manifolds) out of noisy point samples of a self-Intersecting or nearly self-Intersecting planar Curve C. C:[a,b]R?R 2 is self-Intersecting if C(u)=C(v), u v, u,v (a,b) (C(u) is the self-intersection point). We consider only transversal self-intersections, i.e. those for which the tangents of the Intersecting branches at the intersection point do not coincide (C (u)=C(v)). In the presence of noise, Curves which self-intersect cannot be distinguished from Curves which nearly self-intersect. Existing algorithms for Curve reconstruction out of either noisy point samples or pixel data, do not produce a (possibly disconnected) Piecewise Linear 1-manifold approaching the whole point sample. The algorithm implemented in this work uses Principal Component Analysis (PCA) with elliptic support regions near the self-intersections. The algorithm was successful in recovering contours out of noisy slice samples of a surface, for the Hand, Pelvis and Skull data sets. As a test for the correctness of the obtained Curves in the slice levels, they were input into an algorithm of surface reconstruction, leading to a reconstructed surface which reproduces the topological and geometrical properties of the original object. The algorithm robustly reacts not only to statistical non-correlation at the self-intersections (non-manifold neighborhoods) but also to occasional high noise at the non-self-Intersecting (1-manifold) neighborhoods. © 2010 Springer-Verlag
C. Cadavid - One of the best experts on this subject based on the ideXlab platform.
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Ellipse-based principal component analysis for self-Intersecting Curve reconstruction from noisy point sets
The Visual Computer, 2011Co-Authors: O. Ruiz, C. Vanegas, C. CadavidAbstract:Surface reconstruction from cross cuts usually requires Curve reconstruction from planar noisy point samples. The output Curves must form a possibly disconnected 1-manifold for the surface reconstruction to proceed. This article describes an implemented algorithm for the reconstruction of planar Curves (1-manifolds) out of noisy point samples of a self-Intersecting or nearly self-Intersecting planar Curve C . C :[ a , b ]⊂ R → R ^2 is self-Intersecting if C ( u )= C ( v ), u ≠ v , u , v ∈( a , b ) ( C ( u ) is the self-intersection point). We consider only transversal self-intersections, i.e. those for which the tangents of the Intersecting branches at the intersection point do not coincide ( C ′( u )≠ C ′( v )). In the presence of noise, Curves which self-intersect cannot be distinguished from Curves which nearly self-intersect. Existing algorithms for Curve reconstruction out of either noisy point samples or pixel data, do not produce a (possibly disconnected) Piecewise Linear 1-manifold approaching the whole point sample. The algorithm implemented in this work uses Principal Component Analysis (PCA) with elliptic support regions near the self-intersections. The algorithm was successful in recovering contours out of noisy slice samples of a surface, for the Hand , Pelvis and Skull data sets. As a test for the correctness of the obtained Curves in the slice levels, they were input into an algorithm of surface reconstruction, leading to a reconstructed surface which reproduces the topological and geometrical properties of the original object. The algorithm robustly reacts not only to statistical non-correlation at the self-intersections (non-manifold neighborhoods) but also to occasional high noise at the non-self-Intersecting (1-manifold) neighborhoods.
N. Nishimura - One of the best experts on this subject based on the ideXlab platform.
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REGULARISED INTEGRAL EQUATIONS IN CRACK SHAPE DETERMINATION PROBLEMS
2016Co-Authors: N. NishimuraAbstract:Let $D $ be a bounded domain in $R^{2} $ which has a smooth boundary $\partial D $. Also let $S $ be a smooth $non-self$-Intersecting Curve contained in $D $. The 2 dimensional (direct) crack problem for Laplace’s equation is formulated into the following boundary value problem: Find a function $u(x) $ in $D\backslash S $ which satisfie
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REGULARISED INTEGRAL EQUATIONS FOR CRACK SHAPE DETERMINATION PROBLEMS
2016Co-Authors: N. NishimuraAbstract:Let $D $ be a bounded domain in $R^{2} $ having a smooth boundary $\partial D $. This domain $D $ contains a smooth piece of non-self-Intersecting Curve $S $ , or a crack, in its interior. The shape and the location of $S $ , however, remain unknown. We are now interested in determining such geometrical information of $S $ from experimental data obtained i
