The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Tai Yong Wang - One of the best experts on this subject based on the ideXlab platform.
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study on the technology of 3d cutter radius compensation based on direction Vector
International Conference on Mechatronics and Automation, 2010Co-Authors: Tai Yong WangAbstract:Cutter radius compensation is the key technology in CNC system and is the data sources and basis of contour interpolation. It is the necessary premise to guarantee the part contour according to programming track and cutter radius to plan the tool center path, especially the coordinates of the joint points. The concept of Orientation Vector is introduced and a technology of 3D cutter radius compensation based on Vector method is put forward. The theory and method of cutter radius compensation in coordinates linear processing is studied deeply. The corresponding algorithm of tool center path for programming contour is established according to the relation between the geometric elements. Simulation results proved that the algorithm is accurate and feasible.
Rosales Leobardo - One of the best experts on this subject based on the ideXlab platform.
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Partial boundary regularity for co-dimension one area-minimizing currents at immersed $C^{1,\alpha}$ tangential boundary points; full exposition
2017Co-Authors: Rosales LeobardoAbstract:We give partial boundary regularity for co-dimension one absolutely area-minimizing currents at points where the boundary consists of a sum of $C^{1,\alpha}$ submanifolds, possibly with multiplicity, meeting tangentially, given that the current has a tangent cone supported in a hyperplane with constant Orientation Vector; this partial regularity is such that we can conclude the tangent cone is unique. The proof closely follows that giving the boundary regularity result of Hardt and Simon.Comment: 82 pages. See arXiv:1508.04229v2 for an alternate abridged versio
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Partial boundary regularity for co-dimension one area-minimizing currents at immersed $C^{1,\alpha}$ tangential boundary points
2015Co-Authors: Rosales LeobardoAbstract:We give partial boundary regularity for co-dimension one absolutely area-minimizing currents at points where the boundary consists of a sum of $C^{1,\alpha}$ submanifolds, possibly with multiplicity, meeting tangentially, given that the current has a tangent cone supported in a hyperplane with constant Orientation Vector; this partial regularity is such that we can conclude the tangent cone is unique. The proof follows closely the boundary regularity result given by Hardt and Simon in [9].Comment: Made a slight correction to the statement of the main theore
Angulo Jesus - One of the best experts on this subject based on the ideXlab platform.
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Adaptive morphological filters based on a multiple Orientation Vector field dependent on image local features.
'Elsevier BV', 2018Co-Authors: Legaz-aparicio Álvar-ginés, Verdu-monedero Rafael, Angulo JesusAbstract:International audienceThis paper addresses the formulation of adaptive morphological filters based on spatially-variant structuring elements. The adaptivity of these filters is achieved by modifying the shape and Orientation of the structuring elements according to a multiple Orientation Vector field. This Vector field is provided by means of a bank of directional openings which can take into account the possible multiple Orientations of the contours in the image. After reviewing and formalizing the definition of the spatially-variant dilation, erosion, opening and closing, the proposed structuring elements are described. These spatially-variant structuring elements are based on ellipses which vary over the image domain adapting locally their Orientation according to the multiple Orientation Vector field and their shape (the eccentricity of the ellipses) according to the distance to relevant contours of the objects. The proposed adaptive morphological filters are used on gray-level images and are compared with spatially-invariant filters, with spatially-variant filters based on a single Orientation Vector field, and with adaptive morphological bilateral filters. Results show that the morphological filters based on a multiple Orientation Vector field are more adept at enhancing and preserving structures which contains more than one Orientation
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Adaptive morphological filters based on a multiple Orientation Vector field dependent on image local features
'Elsevier BV', 2017Co-Authors: Legaz Aparicio, Alvar Ginés, Verdu-monedero Rafael, Angulo JesusAbstract:This paper addresses the formulation of adaptive morphological filters based on spatially-variant structuring elements. The adaptivity of these filters is achieved by modifying the shape and Orientation of the structuring elements according to a multiple Orientation Vector field. This Vector field is provided by means of a bank of directional openings which can take into account the possible multiple Orientations of the contours in the image. After reviewing and formalizing the definition of the spatially-variant dilation, erosion, opening and closing, the proposed structuring elements are described. These spatially-variant structuring elements are based on ellipses which vary over the image domain adapting locally their Orientation according to the multiple Orientation Vector field and their shape (the eccentricity of the ellipses) according to the distance to relevant contours of the objects. The proposed adaptive morphological filters are used on gray-level images and are compared with spatially-invariant filters, with spatially-variant filters based on a single Orientation Vector field, and with adaptive morphological bilateral filters. Results show that the morphological filters based on a multiple Orientation Vector field are more adept at enhancing and preserving structures which contains more than one Orientation
Serge Van Sint Jan - One of the best experts on this subject based on the ideXlab platform.
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musculoskeletal modeling of the suboccipital spine kinematics analysis muscle lengths and muscle moment arms during axial rotation and flexion extension
Spine, 2011Co-Authors: Pierremichel Dugailly, Stephane Sobczak, Fedor Moiseev, Victor Sholukha, Patrick Salvia, Veronique Feipel, Marcel Rooze, Serge Van Sint JanAbstract:STUDY DESIGN In vitro and modeling study of upper cervical spine (UCS) three-dimensional (3D) kinematics and muscle moment arm (MA) during axial rotation (AR) and flexion extension (FE). OBJECTIVE To create musculoskeletal models with movement simulation including helical axis (HA) and muscle features. SUMMARY OF BACKGROUND DATA Integration of various kinematics and muscle data into specific-specimen 3D anatomical models with graphical representation of HA and muscle Orientation and MA is not reported for the UCS musculoskeletal system. METHODS Kinematics, anatomical, and computed tomographic imaging data were sampled in 10 anatomical specimens. Using technical markers and anatomical landmarks digitizing, spatial position of segments was computed for five discrete positions of AR and FE using a 3D digitizer. To obtain musculoskeletal model simulation, a registration method was used to combine collected data. Processing was performed using Orientation Vector and HA computation and suboccipital muscle features (i.e., length and MA) relative to motion angle. RESULTS Range of motion and coupling were in agreement with previous in vitro studies. HA (i.e., location and Orientation) showed low variation at the occipitoaxial and atlantoaxial levels for FE and AR, respectively. The main Orientation of the HA was vertical at C1-C2 during AR and horizontal at C0-C1 during FE. For muscles MA, absolute peak value (ranging from 20 to 40 mm) occurred at different poses depending on the analyzed muscle and motion. Poor magnitude was found for obliquus capitis inferior and rectus capitis posterior minor in FE and AR, respectively. CONCLUSION On the basis of previous methods, we developed a protocol to create UCS musculoskeletal modeling with motion simulation including HA and suboccipital muscles representation. In this study, simultaneous segmental movement displaying with HA and muscles features was shown to be feasible.
Dongju Chen - One of the best experts on this subject based on the ideXlab platform.
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machining accuracy improvement of non orthogonal five axis machine tools by a new iterative compensation methodology based on the relative motion constraint equation
International Journal of Machine Tools & Manufacture, 2018Co-Authors: Jinwei Fan, Qiaohua Wang, Dongju ChenAbstract:Abstract This paper proposes a new iterative compensation methodology of geometric errors to improve the machining accuracy of a non-orthogonal five-axis machine tool (NOFAMT). Firstly, based on homogeneous transform matrix (HTM) and multi-body system (MBS) theory, the relative motion constraint equations (TRMCEs) of the tool tip position and tool Orientation Vector related to a NOFAMT with a nutating rotary B axis are established. Then, by utilizing TRMCEs, the mapping relationships between tool path and the numerical control (NC) command without and with considering the geometric errors are constructed respectively. In order to truly reproduce tool motion trajectory of the machine tool driven by the given NC command, the mapping relationship between the NC command and tool cutting trajectory is also established. Meanwhile, procedures of iterative compensation are described by using the aforementioned mapping relationships without the traditional inverse calculation, and the actual NC code is generated in self-developed compensation software. It is not difficult to find that the new approach takes the difference between tool path and tool cutting trajectory as the control objective and can directly obtain the actual NC code controlling the machine tool to achieve the desired machining accuracy. Finally, a cutting test is carried out on the DMU60P NOFAMT. Experimental results show the developed iterative compensation methodology is precise and effective for NOFAMTs. Therefore, compared with the existing methods, the new method is more direct and accurate. And its basic idea can be applied to other type of machine tools.
