Generation of Planar Kinematic Chains With One Multiple Joint

2013 ◽  
Author(s):  
Huafeng Ding ◽  
Weijuan Yang ◽  
Peng Huang ◽  
Li Ma ◽  
Andrés Kecskeméthy
Keyword(s):  
Conceptual Design ◽  
Degrees Of Freedom ◽  
Characteristic Number ◽  
Automatic Method ◽  
Topological Graph ◽  
Topological Graphs ◽  
Systematic Method ◽  
Joint Kinematic ◽  
Kinematic Chains ◽  
First Time

It is very important to synthesize as many feasible kinematic structures of mechanisms as possible in the conceptual design of mechanisms. Besides simple joint mechanisms, multiple joint mechanisms are also widely used in various mechanical systems. This paper proposes an automatic method for the synthesis of planar multiple joint kinematic chains which are seldom addressed in literature. The bicolor topological graph and the bicolor contracted graph are adopted to represent the topological structures of multiple joint kinematic chains. The characteristic number string of bicolor topological graphs is proposed and used to detect efficiently isomorphism in the synthesis progress. A systematic method for the synthesis of kinematic chains with one multiple joint is proposed, and the whole families of multiple joint kinematic chains with up to 16 links and all possible degrees of freedom are obtained for the first time.

Automatic Structural Synthesis of Planar Multiple Joint Kinematic Chains

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Huafeng Ding ◽  
Weijuan Yang ◽  
Peng Huang ◽  
Andrés Kecskeméthy
Keyword(s):  
Degrees Of Freedom ◽  
Characteristic Number ◽  
Structural Synthesis ◽  
Topological Graph ◽  
Topological Graphs ◽  
Systematic Method ◽  
Joint Kinematic ◽  
Kinematic Chains ◽  
Mechanical Products ◽  
First Time

It is of great importance in the conceptual creative design of mechanical systems to synthesize as many feasible kinematic structures of mechanisms as possible. However, the methods for the structural synthesis of multiple joint kinematic chains are seldom addressed in literature even though they are widely used in various mechanical products. This paper proposes an automatic method to synthesize planar multiple joint kinematic chains. First, the bicolor topological graph and the bicolor contracted graph are introduced to represent the topological structures of multiple joint kinematic chains. Then, the characteristic number string of bicolor topological graphs is proposed and used to efficiently detect isomorphism in the synthesis progress. Finally, a systematic method for the synthesis of kinematic chains with one multiple joint is proposed, and the whole families of multiple joint kinematic chains with up to 16 links and all possible degrees of freedom are synthesized for the first time.

Unified Topological Representation Models of Planar Kinematic Chains

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Huafeng Ding ◽  
Jing Zhao ◽  
Zhen Huang
Keyword(s):  
Conceptual Design ◽  
Topological Representation ◽  
Topological Graph ◽  
Planar Mechanisms ◽  
Topological Graphs ◽  
Joint Kinematic ◽  
Kinematic Chains ◽  
Mathematical Representations ◽  
Structure Synthesis ◽  
Topological Models

This paper attempts to establish unified topological models and corresponding mathematical representations for planar simple joint, multiple joint, and geared (cam) kinematic chains. First, the conventional topological representation models of kinematic chains are introduced. Then, new topological models of multiple joint and geared (cam) kinematic chains, which are derived from the topological model of simple joint kinematic chains, are presented. The characteristics of the new topological graphs and their associations with the topological graph of simple joint kinematic chains are also addressed. The most important merit of the new topological graphs is that it makes it much easier to undertake unified structure synthesis and further to establish conceptual design platform for various planar mechanisms. Synthesis examples of both multiple joint and geared chains are given, which show the effectiveness of the unified topological models.

Complete Atlas Database of 2-DOF Kinematic Chains and Creative Design of Mechanisms

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Huafeng Ding ◽  
Wenao Cao ◽  
Andrés Kecskeméthy ◽  
Zhen Huang
Keyword(s):  
Creative Process ◽  
Degrees Of Freedom ◽  
Systematic Approach ◽  
Computer Models ◽  
Creative Design ◽  
Kinematic Structure ◽  
Topological Graphs ◽  
Kinematic Chains ◽  
First Time ◽  
Intuitive Manner

The creation of novel kinematic structures of mechanisms still represents a major challenge in the quest for developing new, innovative devices. In this setting, computer models that can automatically generate and visualize all possible independent structures in an intuitive manner prove to be valuable as a support in the creative process of the designer. This paper proposes an automatic approach for establishing the complete atlas database of 2-DOF kinematic chains and a systematic approach for the creative design of mechanisms based on such an atlas. First, the transformation of the kinematic structure into a graph-based representation is addressed. Then, an approach for the generation of all nonfractionated topological graphs of 2-DOF (degrees of freedom) kinematic chains using contracted graphs as well as a method for synthesizing all the fractionated topological graphs through the combination of corresponding 1-DOF kinematic chains are addressed. Based on these methods, the complete atlas database of 2-DOF kinematic chains up to 15 links is established in this paper for the first time. Using this complete database, a systematic approach for the creative design of mechanisms can be derived, as illustrated for the example of an 11-link 2-DOF rode tractor.

The Establishment of Novel Structure Representation Models for Several Kinds of Mechanisms

2009 ◽  
Author(s):  
Huafeng Ding ◽  
Jing Zhao ◽  
Zhen Huang
Keyword(s):  
Topological Graph ◽  
Planar Mechanisms ◽  
Topological Graphs ◽  
Structure Representation ◽  
Joint Kinematic ◽  
Kinematic Chains ◽  
Mathematical Representations ◽  
Novel Structure ◽  
Structure Synthesis ◽  
Topological Models

This paper attempts to establish the unified topological models and corresponding mathematical representations for planar simple joint, multiple joint and geared (cam) kinematic chains. First, the conventional topological representation models of kinematic chains are introduced. Then new topological models of multiple joint and geared (cam) kinematic chains, which are derived from the topological graph of simple joint kinematic chains, are presented. The characteristics of the new topological graphs and their associations with the topological graph of simple joint kinematic chains are also addressed. The most important merit of the new topological graphs is that it makes it much easier to do unified structure synthesis and further establish conceptual design platform for various planar mechanisms of these kinds.

An Automatic Method for Sketching of Planar Simple and Multiple Joint Kinematic Chains

2015 ◽  
Author(s):  
Huafeng Ding ◽  
Peng Huang ◽  
Zhen Huang ◽  
Andrés Kecskeméthy
Keyword(s):  
Mechanical Design ◽  
Kinematic Chain ◽  
Design Stage ◽  
Automatic Method ◽  
Topological Graph ◽  
Joint Kinematic ◽  
Kinematic Chains ◽  
Visual Understanding ◽  
Fully Automatic ◽  
Edge Crossings

The sketching of mechanisms (kinematic chains) shows designers a visual understanding of the interrelationship among links and joints in mechanical design, but sketching of mechanisms in manually in conceptual design stage is time-consuming and inefficient. In this paper, a fully-automatic method for sketching of planar simple and multiple joint kinematic chains is proposed. First, the complete sets of the topological structures (topological graphs and contracted graphs) of both simple and multiple joint kinematic chains are introduced. Then an algorithm for the layouts of the contracted graphs with minimal edge crossings is proposed. Third, the expression set of binary sub-paths derived from a topological graph is obtained for the sketching of the simple joint kinematic chain, and based on the sketching of the simple joint kinematic chains the sketching of corresponding multiple joint kinematic chains is obtained. Finally, both simple and multiple joint kinematic chains with numbers of links and numbers of basic loops are provided in batch as examples to show the effectiveness of the method.

Studying the Optimal Layout of Topological Graphs to Facilitate the Automatic Sketching of Kinematic Chains

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Wenjian Yang ◽  
Huafeng Ding ◽  
Yong He ◽  
Min Wu
Keyword(s):  
Conceptual Design ◽  
Low Complexity ◽  
New Method ◽  
Computer Language ◽  
Optimal Layout ◽  
Topological Graph ◽  
Topological Graphs ◽  
Kinematic Chains ◽  
Two Parameters

The sketching of kinematic chains is important in the conceptual design of mechanisms. In general, the process of sketching kinematic chains can be divided into two steps, namely sketching topological graphs and converting them into the corresponding kinematic chains. This paper proposes a new method to automatically sketch topological graphs including both planar and nonplanar graphs. First, two parameters called moving sign (MS) and moving sign string (MSS) are defined, based on which a new algorithm is proposed to acquire all feasible layouts of the contracted graph by moving inner edges. All topological graphs synthesized from the same contracted graph are identified to have the shared feasible layouts, and another algorithm is proposed to determine the optimal layout for each topological graph. Then, topological graphs are sketched automatically by determining the location of vertices. The method has low complexity and is easy to be programmed using computer language.

scholarly journals Exoskeleton kinematic design robustness: An assessment method to account for human variability

2020 ◽  
Vol 1 ◽  
Author(s):  
Matteo Sposito ◽  
Christian Di Natali ◽  
Stefano Toxiri ◽  
Darwin G. Caldwell ◽  
Elena De Momi ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Pilot Trial ◽  
Kinematic Model ◽  
Assessment Method ◽  
Point Of View ◽  
Systematic Method ◽  
Kinematic Chains ◽  
Subject Variability ◽  
Anchor Points ◽  
Human Joints

Abstract Exoskeletons are wearable devices intended to physically assist one or multiple human joints in executing certain activities. From a mechanical point of view, they are kinematic structures arranged in parallel to the biological joints. In order to allow the users to move while assisted, it is crucial to avoid mobility restrictions introduced by the exoskeleton’s kinematics. Passive degrees of freedom and other self-alignment mechanisms are a common option to avoid any restrictions. However, the literature lacks a systematic method to account for large inter- and intra-subject variability in designing and assessing kinematic chains. To this end, we introduce a model-based method to assess the kinematics of exoskeletons by representing restrictions in mobility as disturbances and undesired forces at the anchor points. The method makes use of robotic kinematic tools and generates useful insights to support the design process. Though an application on a back-support exoskeleton designed for lifting tasks is illustrated, the method can describe any type of rigid exoskeleton. A qualitative pilot trial is conducted to assess the kinematic model that proved to predict kinematic configurations associated to rising undesired forces recorded at the anchor points, that give rise to mobility restrictions and discomfort on the users.

Reliability and Efficiency of the Existing Spectral Methods for Isomorphism Detection

2005 ◽  
Vol 128 (6) ◽  
pp. 1246-1252 ◽  
Author(s):  
Rajesh Pavan Sunkari ◽  
Linda C. Schmidt
Keyword(s):  
Characteristic Polynomial ◽  
Degrees Of Freedom ◽  
Polynomial Method ◽  
Worst Case ◽  
Frobenius Theorem ◽  
Spectral Techniques ◽  
Kinematic Chains ◽  
Correct Proof ◽  
First Time ◽  
Three Degrees Of Freedom

Mechanism researchers have developed several types of codes and indices, to indicate if a pair of kinematic chains is isomorphic. Unfortunately, most of these codes or indices are either computationally inefficient or unreliable. This work establishes, for the first time, the reliability of the existing spectral techniques—characteristic polynomial and eigenvector approaches—for isomorphism detection. The reliability of characteristic polynomial of adjacency matrix is established by determining the number of pairs of non-isomorphic chains, with up to 14 links and one, two, and three degrees of freedom. The most recent eigenvector approach is critically reviewed and correct proof is provided for the statement that is the basis for this approach. It is shown, for the first time, that the eigenvector approach was able to identify all nonisomorphic chains, with up to 14 links and one, two, and three degrees of freedom. It is shown that unlike the characteristic polynomial method the eigenvector approach in worst case might take exponential time. Finally, efficient methods are suggested to the classical eigenvector approach by using the Perron–Frobenius theorem.

Multi-Freedom Planetary Transmission Scheme Based on Graph Theory of Topological Synthesis

2015 ◽  
Author(s):  
Dejun Mu ◽  
Huiying Wang ◽  
Huafeng Ding ◽  
Xiangwei Liu ◽  
Xing Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Transmission Scheme ◽  
Topological Graph ◽  
Kinematic Chains ◽  
Planetary Gearbox ◽  
Comprehensive Method ◽  
Transmission Mechanisms ◽  
Function Diagram ◽  
Planetary Transmission

In order to enrich the synthesis theory of planetary gearbox and meet the needs of multiple gearshifts this paper proposes a comprehensive method for the planetary gear transmission. Based on the topological graph atlas, the kinematic chains of 9-link and 2 degrees of freedom are synthesized. By the topological graph selection principle and gear function diagram transformation principle, 6-speed transmission mechanisms are obtained.

Atlas Database of 2-DOF Kinematic Chains and Its Application to the Creative Design of Mechanisms

2011 ◽  
Author(s):  
Huafeng Ding ◽  
Andre´s Kecskeme´thy ◽  
Zhen Huang
Keyword(s):  
Graph Representation ◽  
Creative Design ◽  
The Novel ◽  
Kinematic Structure ◽  
Performance Indices ◽  
Topological Graphs ◽  
Systematic Method ◽  
Kinematic Chains ◽  
Challenging Issue ◽  
The Creation

Creation of novel kinematic structures of mechanisms has been a challenging issue which is usually conducted on experience and intuition. This paper, however, proposes a systematic method for the creative design of mechanism-based products and equipments on the basis of corresponding atlas database, and the creative design of an 11-link 2-DOF rode tractor is provided as an example. First, the transformation of the kinematic structure of mechanisms into graph representation is addressed. Then, the complete atlas database of 11-link 2-DOF kinematic chains is established by obtaining all the non-fractionated topological graphs through their contracted graphs and all the fractionated topological graphs through the combination of 1-DOF kinematic chains. Finally, based on the established atlas database, the creation design for the novel mechanisms of 11-link 2-DOF rode tractors is implemented, and all the nine novel feasible mechanisms (including the widely used one reported in literature) which satisfy the proposed performance indices are obtained.

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