New Method to Describe the Structure Changing of Metamorphic Mechanisms and Its Application in Structure Synthesis

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.

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Structure Synthesis of 4-DOF (3-Translation and 1-Rotation) Parallel Robot Mechanisms Based on the Units of Single-Opened-Chain

Volume 2B: 27th Design Automation Conference ◽

10.1115/detc2001/dac-21152 ◽

2001 ◽

Author(s):

Ting-Li Yang ◽

Qiong Jin ◽

An-Xin Liu ◽

Fang-Hua Yao ◽

Yu-Feng Luo

Keyword(s):

Parallel Robot ◽

New Method ◽

Structure Synthesis ◽

Topological Characteristics

Abstract Based on the units of single-opened-chain limb, some topological characteristics of rank-degenerate parallel robot mechanisms are revealed, and a systematic and effective new method for structure synthesis of 4-DOF (3-translation and 1-rotation) parallel robot mechanism is put forward in this paper. 50 new mechanisms are synthesized and classified. The method proposed in this paper is of universal significance and has been used for the structure synthesis of rank-degenerate parallel robot mechanisms with other kinematics output types.

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Loop-Structure Decomposition of Kinematic Chains, Application to Rigid Sub-Chain Detection

Volume 8: 31st Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2007-34147 ◽

2007 ◽

Author(s):

Huafeng Ding ◽

Zhen Huang

Keyword(s):

New Method ◽

Loop Structure ◽

Kinematic Chains ◽

Structure Synthesis ◽

Computer Aided ◽

Structure Decomposition ◽

Isomorphism Identification

Rigid sub-chain detection and isomorphism identification are two of the most difficult problems in the computer aided structure synthesis of kinematic chains. Based on the array representation of the loops of kinematic chains, this paper first introduces two operations of loops. Then a new theory of structure decomposition of kinematic chains is proposed on the basis of the concept of the independent loop set. After that a new method grounded on the theory is proposed for rigid sub-chain detection. Finally, the optimized algorithm for structure decomposition is presented and the corresponding program for rigid sub-chain detection is developed as well.

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STRUCTURE SYNTHESIS OF METAMORPHIC MECHANISMS BASED ON THE CONFIGURATION TRANSFORMATIONS

Journal of Mechanical Engineering ◽

10.3901/jme.2002.07.012 ◽

2002 ◽

Vol 38 (07) ◽

pp. 12 ◽

Cited By ~ 17

Author(s):

Duanling Li

Keyword(s):

Structure Synthesis ◽

Metamorphic Mechanisms

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Structure Synthesis of Multi-DOF Planar Metamorphic Mechanisms With a Single Driver

10.1115/1.0001952v ◽

2021 ◽

Author(s):

Qiang Yang ◽

Andrew Murray ◽

Dave Myszka ◽

Shujun Li

Keyword(s):

Structure Synthesis ◽

Metamorphic Mechanisms

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Structure Synthesis of Single-Driven Metamorphic Mechanisms Based on the Augmented Assur Groups

Journal of Mechanisms and Robotics ◽

10.1115/1.4006741 ◽

2012 ◽

Vol 4 (3) ◽

Cited By ~ 35

Author(s):

Shujun Li ◽

Jian S. Dai

Keyword(s):

Structure Formation ◽

Class Ii ◽

Composition Rule ◽

Class Iii ◽

Planar Mechanisms ◽

Kinematic Synthesis ◽

Structure Synthesis ◽

The One ◽

Synthesis Methodology ◽

Metamorphic Mechanisms

This paper presents a new way of structure composition of single-driven metamorphic mechanisms to develop a systematic and modularized structure synthesis methodology of metamorphic mechanisms based on augmented Assur groups (AAGs). Planar metamorphic mechanisms can hence be constructed based on the developed AAGs by applying the structure composition rule of general planar mechanisms formed by Assur groups (AGs). First, the one-mobility AAGs are introduced based on class II and class III AGs; the structure formulation and composition methodology of planar metamorphic mechanisms are then proposed based on the AAGs, and the basic problems including mobility and synthesis of constrained metamorphic working mobility-configuration are investigated. This leads to the investigation of the degenerated equivalent AGs of AAGs in the metamorphic process and the corresponding kinematic characteristics, providing references for kinematic synthesis of metamorphic mechanisms. Further, a typical spatial metamorphic group is introduced based on the concept of AAGs, and the structure formation and composition of spatial metamorphic mechanisms are presented. Examples show that both planar and spatial metamorphic mechanisms can be constructed by utilizing the one-mobility blocks extended from the AGs.

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Selective Sampling and Orientation of Non-Homogeneous Tissues

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100238 ◽

1968 ◽

Vol 26 ◽

pp. 98-99

Author(s):

C. C. Clawson ◽

L. W. Anderson ◽

R. A. Good

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Light Microscopy ◽

Random Sampling ◽

New Method ◽

Microscope Examination ◽

Small Areas ◽

Selective Sampling ◽

Large Numbers ◽

Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

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