Kinematic Synthesis of Deployable-Foldable Truss Structures Using Graph Theory, Part 1: Graph Generation

1995 ◽  
Vol 117 (1) ◽  
pp. 112-116 ◽  
Author(s):  
D. B. Warnaar ◽  
M. Chew
Keyword(s):  
Graph Theory ◽  
Conceptual Design ◽  
Design Process ◽  
Degrees Of Freedom ◽  
Truss Structure ◽  
Truss Structures ◽  
Structural Synthesis ◽  
Deployable Structures ◽  
Kinematic Synthesis ◽  
Graph Generation

Kinematic structural synthesis has been relatively successful when applied to the conceptual design of mechanisms. The approach presented in this paper, however, views the design process from an initial standpoint of a truss structure. First, graphs are generated that represent truss structures with a given number of nodes and links. Each graph is then modified by designating certain edges in the graph to represent links in the structure that incorporate additional degrees of freedom. In so doing, the graph of a structure is transformed into one representing a mechanism. A procedure is presented that enables the exhaustive generation of these graphs for deployable structures of any given number of nodes and links. From these graphs, it is then possible to obtain enumerable novel deployable truss structures as well as those that have been reported in the literature.

The Conceptual Design of Differential Mechanisms

2013 ◽  
Vol 284-287 ◽  
pp. 973-978
Author(s):  
Chia Chun Chu
Keyword(s):  
Conceptual Design ◽  
Design Process ◽  
Degrees Of Freedom ◽  
Geometric Constraints ◽  
The Other ◽  
Design Approach ◽  
Process Step ◽  
Two Degrees Of Freedom ◽  
Number Synthesis

The purpose of this paper is to present a design approach based on the geometric constraints of joints for synthesizing differential mechanisms with two degrees-of-freedom, including some mechanisms with the same functions but distinct structures. The concept of virtual axes is presented. And, there are five steps in the design process. Step 1 is to decide fundamental entities by the properties of existing mechanisms and the technique of number synthesis, and 10 suitable fundamental entities of differential mechanisms are available. Step 2 is to compose geometric constraints, and 14 items are obtained. Step 3 is to compose links, and 15 items are derived. Step 4 is to assign fixed constraints for inputs or outputs, and 15 results are found. The final step is to particularize the obtained events by the properties of existing mechanisms and the structures of fundamental entities. As a result, 8 feasible results for differential mechanisms with two degrees-of-freedom and two basic loops are obtained in which 2 are existing designs and the other 6 are novel.

Constraint Representation Based on Lie Algebra in a Kinematic Model and Synthesis of Mechanisms

2000 ◽  
Author(s):  
Hitoshi Tokunaga ◽  
Satoshi Imamura
Keyword(s):  
Lie Algebra ◽  
Conceptual Design ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Analysis Procedure ◽  
New Method ◽  
Structural Synthesis ◽  
Synthesis Of Mechanisms ◽  
Mechanical Products ◽  
Synthesis Procedure

Abstract This paper deals with a new method for structural synthesis of mechanisms in a conceptual design as follows: first, using the Lie algebra-based representation of constraint on degrees of freedom, we propose an analysis procedure of the degrees of freedom between components in mechanisms of mechanical products. Second, this analysis procedure makes it possible to propose a structural synthesis procedure. Third, in order to select one of the mechanisms generated by the synthesis procedure, we introduce the concept of manipulatability as a criterion for the evaluation. Finally, to evaluate the usefulness of the proposed method, it is applied to an example of structural synthesis.

Topological Representations and Characteristics of Variable Kinematic Joints

2005 ◽  
Vol 128 (2) ◽  
pp. 384-391 ◽  
Author(s):  
Hong-Sen Yan ◽  
Chin-Hsing Kuo
Keyword(s):  
Graph Theory ◽  
Degrees Of Freedom ◽  
Structural Synthesis ◽  
Characteristic Analysis ◽  
Push Button ◽  
Walking Machines ◽  
Operation Process ◽  
Variable Topology ◽  
Topological Characteristics ◽  
Kinematic Joint

There exist some mechanisms with variable topologies that have interesting applications, for examples, legged walking machines, mechanical push-button stopper locks, and various toys. A variable kinematic joint is a kinematic joint that is capable of topological variation in a mechanism with variable topology. This work aims at the topological representations and characteristic analysis of variable kinematic joints. During the operation process of a mechanism, the topology states of a variable kinematic joint can be expressed symbolically as the joint sequences, graphically the digraphs, and mathematically the matrices. With the applications of graph theory, it proves that the topological characteristics of variable kinematic joints appeared with the abilities of reversibility, continuity, variability of degrees of freedom, joint homomorphism, contractibility, and expansibility. Two examples are provided for illustrating how the proposed concepts can be used to analyze and synthesize the variable joints. The results of this work provide a logical foundation for the systematic structural synthesis regarding the kinematic joints and mechanisms with variable topologies.

Kinematic Synthesis of Deployable-Foldable Truss Structures Using Graph Theory, Part 2: Generation of Deployable Truss Module Design Concepts

1995 ◽  
Vol 117 (1) ◽  
pp. 117-122 ◽  
Author(s):  
D. B. Warnaar ◽  
M. Chew
Keyword(s):  
Graph Theory ◽  
Truss Structures ◽  
Kinematic Synthesis ◽  
Design Concepts ◽  
Module Design

A special type of truss structures, called truss modules, is presented. Graphs of this class of structures form a subset of the graphs that are generated using the approach presented in Part 1. Two procedures are presented that are applied to recognize these graphs among graphs of truss structures. The procedures also generate information on the relative lengths of the links in a truss module by examining the graph it represents. This enables the generation of numerous novel (deployable) truss modules as well as those that have been reported in the literature. Promising alternatives to existing designs are identified.

A New Approach to Conceptual Design Based on Path Decomposition of Digraph

2011 ◽  
Vol 52-54 ◽  
pp. 73-78
Author(s):  
De Zhen Zhang ◽  
Wei Shi Zhang ◽  
Jian Ming Zhang
Keyword(s):  
Graph Theory ◽  
Conceptual Design ◽  
Design Process ◽  
Basic Element ◽  
New Approach ◽  
Path Decomposition ◽  
Single Mechanism ◽  
Feasible Solutions

A new approach to conceptual design based on path decomposition of digraph is presented in the paper. The set of basic mechanisms is firstly defined and every single mechanism is taken as a basic element in the set. The relationships among basic elements are described with paths or loops in the graph theory. Therefore, the conceptual design can be visualized as searching a suitable loop in the set of basic mechanisms. The digraph and the path decomposition in the graph theory are applied to represent solutions of conceptual design, such as the sequence, existence and the concatenation formation and repetition. And then, an illation formula is derived and a construction tree of conceptual design process is provided. The generated schemes are further filtered using character restriction operation which followed corresponding rules, so as to identify feasible solutions. Finally, a design example is given to demonstrate the effectiveness of the proposed approach.

Driving Characteristic Analysis of a Planar Deployable Support Truss Structure for Space Antenna

2013 ◽  
Vol 373-375 ◽  
pp. 54-64
Author(s):  
Dan Dan Wang ◽  
Qiang Cong ◽  
Rong Qiang Liu ◽  
Cong Fa Zhang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Closed Loop ◽  
Truss Structure ◽  
Truss Structures ◽  
Space Structures ◽  
Characteristic Analysis ◽  
Space Antenna ◽  
Deployable Structures ◽  
Fast Analysis ◽  
Driving Torque ◽  
Deployment Analysis

As the development of space structures is increasing fast, analysis on the characteristics of those deployable structures deserve to be paid enough attention to ensure a reliable deployment on orbit. For a deployable truss structure, more than one position can be chosen as the driving positions, especially when the structure has not only 1 degree of freedom (DOF), an available choice of the driving positions shows significant importance on the performance of the space deployable structure. This paper mainly deals with a planar deployable support truss structure for space antenna by means of the closed loop equations and the Kane equation to discuss the deployment characteristics by comparison of the driving torque needed over time. A full comparison of all the possible examples of deployment analysis results under different driving modes is presented. The results show the importance of the choice of driving movements and the design of parameters and also provide a useful reference to other related truss structures.

An Application of Graph Theory for the Detection of Degenerate Structures in Planetary Gear Trains

2021 ◽  
Author(s):  
Essam L. Esmail ◽  
Anahed H. Juber
Keyword(s):  
Graph Theory ◽  
Adjacency Matrix ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Connectivity Matrix ◽  
Structural Synthesis ◽  
Multiple Degrees Of Freedom ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Straightforward Approach

Abstract One of the most important steps in the structural synthesis of planetary gear trains is to eliminate degenerate structures. First, the graph theory is used to represent planetary gear trains (PGTs). Second, a procedure is developed to identify fundamental geared entities (FGEs). Further, the single-planet FGEs are shown to have one-DOF and, therefore, cannot constitute a degenerate structure. It is this that allows a significant reduction in the calculation in relation to other methods of diagnosing degenerate structures. Third, using the concepts of FGEs and the notation of the associated adjacency matrix, an algorithm is developed for the detection of degenerate structures in PGTs. The algorithm is based on the fact that any degenerate structure is a PGT formed by two fundamental geared entities with common edges and/or vertices equal to or more than 3. Forth, the concept of connectivity between single-planet FGEs is introduced and a simple, straightforward approach for deducting the connectivity matrix from the adjacency matrix is developed. The new vertex-edge mobility criterion does not require combinatorial analysis. Besides, the method is applicable to one and multiple degrees of freedom PGTs, it is also applicable to multi-planet PGTs and complex PGTs, including contrary examples found in the literature.

scholarly journals Conceptual Design of Electromechanical Actuation Systems for Large-Sized Directional Control Valves

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 133
Author(s):  
Tobias Vonderbank ◽  
Katharina Schmitz
Keyword(s):  
Conceptual Design ◽  
Design Process ◽  
Operating Conditions ◽  
Function Structure ◽  
Advantages And Disadvantages ◽  
Conceptual Designs ◽  
Actuation Systems ◽  
Electromechanical Actuation ◽  
Function Structures ◽  
Valve Actuation

Increasing performance in modern hydraulics is achieved by a close investigation of possible enhancements of its components. Prior research has pointed out that electromechanical actuators can form suitable alternatives to hydraulically piloted control systems. Since the requirements at these actuation systems depend on the operating conditions of the system, each actuator can be optimized to the respective hydraulic system. Considering that many different conceptual designs are suitable, the phase of conceptual design plays a decisive role during the design process. Therefore, this paper focuses on the process of developing new conceptual designs for electromechanical valve actuation systems using the method of function structures. Aiming to identify special design features, which need to be considered during the design process of electromechanical actuation systems, an exemplary actuator was designed based on the derived function structure. To highlight the potential of function structures for the development of new electromechanical valve actuation systems, two principal concepts, which allow the reduction of the necessary forces, have been developed by extending the function structure. These concepts have been experimentally investigated to identify their advantages and disadvantages.

scholarly journals Explicating concepts in reasoning from function to form by two-step innovative abductions

2016 ◽  
Vol 30 (2) ◽  
pp. 125-137 ◽  
Author(s):  
Ehud Kroll ◽  
Lauri Koskela
Keyword(s):  
Conceptual Design ◽  
Design Process ◽  
Abductive Reasoning ◽  
Parameter Analysis ◽  
Critical Examination ◽  
Functional Aspect ◽  
Specific Design ◽  
Design Processes ◽  
Step Process ◽  
Design Reasoning

AbstractThe mechanism of design reasoning from function to form is suggested to consist of a two-step inference of the innovative abduction type. First is an inference from a desired functional aspect to an idea, concept, or solution principle to satisfy the function. This is followed by a second innovative abduction, from the latest concept to form, structure, or mechanism. The intermediate entity in the logical reasoning, the concept, is thus made explicit, which is significant in following and understanding a specific design process, for educating designers, and to build a logic-based computational model of design. The idea of a two-step abductive reasoning process is developed from the critical examination of several propositions made by others. We use the notion of innovative abduction in design, as opposed to such abduction where the question is about selecting among known alternatives, and we adopt a previously proposed two-step process of abductive reasoning. However, our model is different in that the two abductions used follow the syllogistic pattern of innovative abduction. In addition to using a schematic example from the literature to demonstrate our derivation, we apply the model to an existing, empirically derived method of conceptual design called “parameter analysis” and use two examples of real design processes. The two synthetic steps of the method are shown to follow the proposed double innovative abduction scheme, and the design processes are presented as sequences of double abductions from function to concept and from concept to form, with a subsequent deductive evaluation step.

A model of the mechanical design process based on empirical data

1988 ◽  
Vol 2 (1) ◽  
pp. 33-52 ◽  
Author(s):  
David G. Ullman ◽  
Thomas G. Dietterich ◽  
Larry A. Stauffer
Keyword(s):  
Problem Solving ◽  
Detailed Analysis ◽  
Conceptual Design ◽  
Design Process ◽  
Empirical Data ◽  
Mechanical Design ◽  
Level Of Detail ◽  
Cad Tools ◽  
Design Alternatives ◽  
Key Features

This paper describes the task/episode accumulation model (TEA model) of non-routine mechanical design, which was developed after detailed analysis of the audio and video protocols of five mechanical designers. The model is able to explain the behavior of designers at a much finer level of detail than previous models. The key features of the model are (a) the design is constructed by incrementally refining and patching an initial conceptual design, (b) design alternatives are not considered outside the boundaries of design episodes (which are short stretches of problem solving aimed at specific goals), (c) the design process is controlled locally, primarily at the level of individual episodes. Among the implications of the model are the following: (a) CAD tools should be extended to represent the state of the design at more abstract levels, (b) CAD tools should help the designer manage constraints, and (c) CAD tools should be designed to give cognitive support to the designer.

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