scholarly journals Recognition of Kinematic Joints of 3D Assembly Models Based on Reciprocal Screw Theory

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Tao Xiong ◽  
Liping Chen ◽  
Jianwan Ding ◽  
Yizhong Wu ◽  
Wenjie Hou
Keyword(s):  
Kinematic Analysis ◽  
Screw Theory ◽  
Geometric Constraints ◽  
Assembly Model ◽  
Matrix Space ◽  
Fast Analysis ◽  
Cad Systems ◽  
Different Types ◽  
3D Assembly ◽  
Kinematic Joint

Reciprocal screw theory is used to recognize the kinematic joints of assemblies restricted by arbitrary combinations of geometry constraints. Kinematic analysis is common for reaching a satisfactory design. If a machine is large and the incidence of redesign frequent is high, then it becomes imperative to have fast analysis-redesign-reanalysis cycles. This work addresses this problem by providing recognition technology for converting a 3D assembly model into a kinematic joint model, which is represented by a graph of parts with kinematic joints among them. The three basic components of the geometric constraints are described in terms of wrench, and it is thus easy to model each common assembly constraint. At the same time, several different types of kinematic joints in practice are presented in terms of twist. For the reciprocal product of a twist and wrench, which is equal to zero, the geometry constraints can be converted into the corresponding kinematic joints as a result. To eliminate completely the redundant components of different geometry constraints that act upon the same part, the specific operation of a matrix space is applied. This ability is useful in supporting the kinematic design of properly constrained assemblies in CAD systems.

Fully Free-Form Deformation Features (δ-F4) Incorporating Discontinuities

2004 ◽  
Author(s):  
Vincent Cheutet ◽  
Jean-Philippe Pernot ◽  
Jean-Claude Leon ◽  
Bianca Falcidieno ◽  
Franca Giannini
Keyword(s):  
Surface Deformation ◽  
Geometric Constraints ◽  
Free Form ◽  
Initial Surface ◽  
Cad Systems ◽  
Free Form Deformation ◽  
Deformation Features ◽  
Generate Surface ◽  
Prototype Software ◽  
Free Form Surfaces

To limit low-level manipulations of free-form surfaces, the concept of Fully Free Form Deformation Features (δ-F4) have been introduced. They correspond to shapes obtained by deformation of a surface area according to specified geometric constraints. In our work, we mainly focused on those features aimed at enforcing the visual effect of the so-called character lines, extensively used by designers to specify the shape of an object. Therefore, in the proposed approach, 3D lines are used to drive surface deformation over specified areas. Depending on the wished shape and reflection light effects, the insertion of character lines may generate surface tangency discontinuities. In CAD systems, such kind of discontinuities is generally created by a decomposition of the initial surface into several patches. This process can be tedious and very complex, depending on the shape of the deformation area and the desired surface continuity. Here, a method is proposed to create discontinuities on a surface, using the trimming properties of surfaces. The corresponding deformation features produce the resulting surface in a single modification step and handle simultaneously more constraints than current CAD systems. The principle of the proposed approach is based on arbitrary shaped discontinuities in the parameter domain of the surface to allow the surface exhibiting geometric discontinuities at user-prescribed points or along lines. The proposed approach is illustrated with examples obtained using our prototype software.

Creation of Assembly Models to Support Automated Concept Generation

2005 ◽  
Author(s):  
Venkat Rajagopalan ◽  
Cari R. Bryant ◽  
Jeremy Johnson ◽  
Daniel A. McAdams ◽  
Robert B. Stone ◽  
...  
Keyword(s):  
Consumer Products ◽  
Design Tool ◽  
Concept Generation ◽  
Assembly Model ◽  
Model Method ◽  
Modeling Process ◽  
Structural Interactions ◽  
Different Types ◽  
Flow Interactions ◽  
Assembly Models

This paper presents an assembly model process that fully characterizes the structural and flow interactions between artifacts in a product. Reverse engineering techniques were employed during the analysis of thirty-three existing consumer products to arrive at a concise standardization of the modeling process. During the product investigation, four different types of structural interactions were identified. These structural interactions, couple, secure, position and guide, were defined using a standardized vocabulary of functional terms. These four structural interactions are rigorously described in this paper in an effort to outline an assembly model method that is accurate and repeatable. Additionally, flow interactions between components are also characterized within the presented modeling technique. A rough representation of the artifact configuration of a product can also be achieved through placement of the component structures in the model. Analysis of the consumer product set also revealed that a new design tool can be generated using the structural interaction information contained in the described assembly models.

Geometric Reasoning on Molding Planning for Multishot Mold Design

2006 ◽  
Vol 6 (3) ◽  
pp. 241-251 ◽  
Author(s):  
Zhou-Ping Yin ◽  
Han Ding ◽  
You-Lun Xiong
Keyword(s):  
Design Method ◽  
Automated Design ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Assembly Planning ◽  
Material Objects ◽  
Mold Design ◽  
Assembly Model ◽  
Contact Graph ◽  
Planning Approach

This paper presents algorithms for automated design of multishot molds for manufacturing multimaterial or multicolor objects, and focuses on molding planning that determines a sequence of mold stages required to produce the desired object. By modeling a multimaterial object as an assembly of homogenous components, a geometric reasoning approach is proposed to generate feasible or practical mold stage sequences by combining the assembly planning approach and the two-plate mold design method. First, a graph-based assembly model, namely the attributed contact graph, is derived from the B-rep models of the constituent components of the gross object by detecting and representing all the contacts between mating components explicitly. Then, all feasible mold stage sequences, represented by an AND/OR graph, are generated by reasoning on geometric constraints due to the demoldability and connectedness requirements using an assembly-by-disassembly strategy. Depending on its demoldability, each component is to be made by one of the three basic molding strategies with varied mold stages and/or mold pieces. To narrow the choice, an optimal or practical molding plan is searched from the feasible molding plans according to some criteria such as the number of mold stages, the number of side cores, and flatness of the parting line. Finally, starting from the last mold stage, mold pieces for each mold stage of the selected molding plan are constructed recursively. The feasibility of the proposed algorithms is demonstrated through an implemented prototypical system, which has been tested successfully with various multi-material objects.

An application of screw theory to the kinematic analysis of a Delta-type robot

2014 ◽  
Vol 28 (9) ◽  
pp. 3785-3792 ◽  
Author(s):  
Jaime Gallardo-Alvarado ◽  
Albert L. Balmaceda-Santamaría ◽  
Eduardo Castillo-Castaneda
Keyword(s):  
Kinematic Analysis ◽  
Screw Theory ◽  
Delta Type

Topology and Constraint Analysis of Phase Change in the Metamorphic Chain and Its Evolved Mechanism

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Ketao Zhang ◽  
Jian S. Dai ◽  
Yuefa Fang
Keyword(s):  
Phase Change ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Evolutionary Process ◽  
Geometric Constraints ◽  
Structure Evolution ◽  
Kinematic Pair ◽  
Motion Patterns ◽  
Metamorphic Mechanism ◽  
Topological State

This paper presents a metamorphic kinematic pair extracted from origami folds in the context of mechanisms, its evolved metamorphic chain, and the novel metamorphic parallel mechanism. This paper starts from the generic issues of topological representation for metamorphic mechanism, leading to unified elementary matrix operation for presentation of topological variation. Phase matrix and augmented adjacency matrix are developed to present the topological state and geometry of metamorphic mechanism in an evolutionary process. The metamorphic kinematic pair has the ability of changing mobility to generate different motion patterns based on mobility change correlated with the link annex induced topological phase change. This paper then investigates topological variation of the metamorphic chain and the topological subphases are enumerated in accordance with structure evolution. Using the metamorphic chain as chain-legs, a multiloop metamorphic mechanism with ability of performing phase change and orientation switch is constructed. The disposition of constraints and geometric constraints induced bifurcated motion are analyzed based on screw theory. The topological variation of the metamorphic parallel mechanism is addressed and the foldability is verified by physical device.

Exploration of the Modeling Process of Assembly Based on MBD and Pro/ENGINEER

2013 ◽  
Vol 753-755 ◽  
pp. 880-883
Author(s):  
Li Xin Wang ◽  
Ming Yue Guo ◽  
Yu Guo
Keyword(s):  
Product Information ◽  
Three Dimensional ◽  
Product Lifecycle Management ◽  
Technical Requirement ◽  
Assembly Model ◽  
Bill Of Materials ◽  
Modeling Process ◽  
Assembly Drawing ◽  
3D Assembly ◽  
Lifecycle Management

The 3D (three dimensional) assembly model should provide all of the product information in order to realize pure 3D modeling in PLM(Product Lifecycle Management). This paper briefly introduces the development of MBD (Model-based Definition) at first, and then the overall information needed in 2D (two dimensional) assembly drawing is presented. At last, the overall needed information (dimensions, technical requirement, BOM(Bill of Materials)) is acted upon 3D assembly model successfully through the use of functions, for example, annotation, layer and view in Pro/ENGINEER.

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