Topology and Constraint Analysis of Reconfiguration in Metamorphic Mechanisms

2010 ◽  
Author(s):  
Ketao Zhang ◽  
Jian S. Dai ◽  
Yuefa Fang ◽  
Zi-Qiang Zhu
Keyword(s):  
Phase Change ◽  
Adjacency Matrix ◽  
Matrix Phase ◽  
Topological Phase ◽  
Revolute Joints ◽  
Constraint Analysis ◽  
Metamorphic Mechanisms

This paper investigates the reconfiguration of the metamorphic mechanisms and proposes mechanism topology matrix, phase matrix and augmented adjacency matrix to identify variation of geometric and topological configurations. This is then used to investigate the two generic ways in the study of induced constraint change of the metamorphic mechanisms. The topological phase change of the metamorphic mechanisms correlative to the variable-axis revolute joints and link annex is hence investigated and constraint analysis is then presented in the working phases of the new metamorphic mechanisms.

Photonic topological phase transition with phase-change materials

2020 ◽  
Author(s):  
Takahiro Uemura ◽  
Hisashi Chiba ◽  
Taiki Yoda ◽  
Yuto Moritake ◽  
Yusuke Tanaka ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Phase Change Materials ◽  
Topological Phase ◽  
Topological Phase Transition

Configuration Based Improved Synthesis of Metamorphic Mechanisms

2009 ◽  
Author(s):  
Duanling Li ◽  
Zhonghai Zhang ◽  
Jian S. Dai ◽  
J. Michael McCarthy
Keyword(s):  
Adjacency Matrix ◽  
Matrix Transformations ◽  
Mechanism Synthesis ◽  
Matrix Operation ◽  
Elementary Matrix ◽  
Matrix Operations ◽  
The Matrix ◽  
Potential Applications ◽  
Synthesis Procedure ◽  
Metamorphic Mechanisms

Metamorphic mechanisms are a class of mechanisms that change their mobility during motions. The deployable and retractable characteristics of these unique mechanisms generate much interest in further investigating their behaviors and potential applications. This paper investigates the resultant configuration variation based on adjacency matrix operation and an improved approach to mechanism synthesis is proposed by adopting elementary matrix operations on the configuration states so as to avoid some omissions caused by existing methods. The synthesis procedure begins with a final configuration of the mechanism, then enumerates possible combinations of different links and associates added links with the binary inverse operations in the matrix transformations of the configuration states, and finally obtains a synthesis result. An algorithm is presented and the topological symmetry of links is used to reduce the number of mechanisms in the synthesis. Some mechanisms of this kind are illustrated as examples.

Preparation and Performance of Gypsum Matrix Phase Change Energy-Storage Material

2012 ◽  
Vol 476-478 ◽  
pp. 1829-1832
Author(s):  
Qi Jin Li ◽  
Guo Zhong Li
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Water Absorption ◽  
Temperature Control ◽  
Matrix Phase ◽  
Expanded Perlite ◽  
Storage Material ◽  
Control Effect ◽  
Energy Storage Material ◽  
And Performance

Paraffin/expanded perlite composite phase change energy-storage material (PPCM) was prepared with expanded perlite as adsorption material and paraffin as phase change energy-storage material (PCM). The DSC and SEM results showed that the internal micropores of expanded perlite were filled with paraffin; the phase change temperature of PPCM was basically similar with that of paraffin and the latent heat of PPCM was corresponded with that of paraffin based on mass ratio among PPCM. PPCM was incorporated into gypsum to prepare gypsum matrix phase change energy-storage material (GPCM), and its mechanical properties, water absorption and temperature control effect were determined. The results showed that with the increase of PPCM’s content, the 2h compressive strength, flexure Strength and water absorption of GPCM continuously declined and its temperature control effect significantly enhanced.

Block Adjacency Matrix Method for Analyzing the Configuration Transformations of Metamorphic Parallel Mechanisms

2014 ◽  
Author(s):  
Duanling Li ◽  
Chunxia Li ◽  
Zhonghai Zhang ◽  
Xianwen Kong
Keyword(s):  
Adjacency Matrix ◽  
Matrix Method ◽  
Parallel Mechanism ◽  
New Method ◽  
Parallel Mechanisms ◽  
Adjacency Matrices ◽  
Moving Platform ◽  
Internal Configuration ◽  
Spherical Motion ◽  
Metamorphic Mechanisms

Metamorphic transformation is a fundamental and key issue in the design and analysis of metamorphic mechanisms. It is tedious to represent and calculate the metamorphic transformations of metamorphic parallel mechanisms using the existing adjacency matrix method. To simplify the configuration transformation analysis, we propose a new method based on block adjacency matrix to analyze the configuration transformations of metamorphic parallel mechanisms. A block adjacency matrix is composed of three types of elements, including limb matrices that are adjacency matrices each representing a limb of a metamorphic parallel mechanism, row matrices each representing how a limb is connected to the moving platform, and column matrices each representing how a limb is connected to the base. Manipulations of the block adjacency matrix for analyzing the metamorphic transformations are presented systematically. If only the internal configuration of a limb changes, the configuration transformations can be obtained by simply calculating the corresponding limb matrix. A 3-URRRR metamorphic parallel mechanism, which has five configurations including a 1-DOF translation configuration and a 3-DOF spherical motion configuration, is taken as an example to illustrate the effectiveness of the proposed approach to the metamorphic transformation analysis of metamorphic parallel mechanism.

scholarly journals A holographic matrix representation of the metamorphic parallel mechanisms

2019 ◽  
Vol 10 (2) ◽  
pp. 437-447
Author(s):  
Wei Sun ◽  
Jianyi Kong ◽  
Liangbo Sun
Keyword(s):  
Adjacency Matrix ◽  
Topological Structure ◽  
Incidence Matrix ◽  
Matrix Representation ◽  
Evolutionary Relationships ◽  
Parallel Mechanisms ◽  
Metamorphic Mechanism ◽  
The Matrix ◽  
Metamorphic Mechanisms

Abstract. Metamorphic mechanisms belong to the class of mechanisms that are able to change their configurations sequentially to meet different requirements. In this paper, a holographic matrix representation for describing the topological structure of metamorphic mechanisms was proposed. The matrix includes the adjacency matrix, incidence matrix, links attribute and kinematic pairs attribute. Then, the expanded holographic matrix is introduced, which includes driving link, frame link and the identifier of the configurations. Furthermore, a matrix representation of an original metamorphic mechanism is proposed, which has the ability to evolve into various sub-configurations. And evolutionary relationships between mechanisms in sub-configurations and the original metamorphic mechanism are determined distinctly. Examples are provided to demonstrate the validation of the method.

Assur-Group Inferred Structural Synthesis for Planar Mechanisms

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Shujun Li ◽  
Hongguang Wang ◽  
Jian S. Dai
Keyword(s):  
Adjacency Matrix ◽  
Synthesis Method ◽  
Matrix Group ◽  
Structural Synthesis ◽  
Planar Mechanisms ◽  
Comprehensive List ◽  
Assur Group ◽  
The Given ◽  
First Time ◽  
Metamorphic Mechanisms

In order to obtain a comprehensive list of possible mechanisms with various choices of both R and P pairs and mechanism inversion of planar mechanisms, a new structural synthesis method is developed by integrating Assur groups (AGs) as elements in the newly developed group-based adjacency matrix. This extended adjacency matrix is proposed with the diagonal elements representing three fundamental elements as the frame link, driving link, AG and augmented AG (AAG) if metamorphic mechanisms are to be synthesized. The off-diagonal elements provide information on group combination and connection forms of the above three fundamental elements and that on the associated kinematic pairs. Based on the extended adjacency matrix, all assembly modes for the given AGs can be established and isomorphism mechanisms can be identified at the same time. Considering all types of the AGs in the extended adjacency matrix, group permutation and combination are used and connection forms are generated including variation of the driving link and mechanism inversion. The structural synthesis is then extending to generating a comprehensive list of types of mechanisms and illustrated by the synthesis for class II 6-bar planar mechanisms with both R and P pairs, generating a list of 588 types of mechanisms that are derived for the first time. The paper further applies the approach to metamorphic mechanisms, and obtained five connection forms of the 7-bar 2DOF metamorphic mechanisms.

Geometry and Constraint Based Design of Metamorphic Parallel Mechanisms

2011 ◽  
Author(s):  
Ketao Zhang ◽  
Jian S. Dai ◽  
Yuefa Fang
Keyword(s):  
Phase Change ◽  
Independent Set ◽  
Parallel Mechanisms ◽  
Revolute Joints ◽  
Geometric Conditions ◽  
Underlying Principle ◽  
Limb Structure

This paper presents two general metamorphic kinematic units which employ only revolute joints. The two kinematic units with reconfigurability are mapped from independent set of line vectors with different geometry. The underlying principle of the metamorphosis of this kind of reconfigurable kinematic units is unraveled by investigating the dependency of corresponding screw system comprised with line vectors. Limb structure that can be used for constructing new parallel mechanisms is proposed. Subphases of the limb are enumerated accompanying to the phase change of the embodied metamorphic units and constraints corresponding to each phase are analyzed based on reciprocity of screws. Two metamorphic parallel mechanisms which can change their configuration from fully 6-DOF phase to 3-DOF translational subphase and 3-DOF spherical subphase are proposed according to geometric conditions that must be met by limbs. The mobility changes of the platform induced by phase change of limbs are addressed.

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