A Novel Symbolic OBDD Algorithm for Generating Mechanical Assembly Sequences Using Decomposition Approach

2011 ◽  
Vol 201-203 ◽  
pp. 24-29
Author(s):  
Zhou Bo Xu ◽  
Tian Long Gu ◽  
Liang Chang ◽  
Feng Ying Li
Keyword(s):  
Assembly Sequence Planning ◽  
The Novel ◽  
Mechanical Assembly ◽  
Breadth First Search ◽  
Decomposition Approach ◽  
Translation Function ◽  
Assembly Sequences ◽  
Cut Set ◽  
Connected Subgraphs ◽  
Induced Graph

The compact storage and efficient evaluation of feasible assembly sequences is one crucial concern for assembly sequence planning. The implicitly symbolic ordered binary decision diagram (OBDD) representation and manipulation technique has been a promising way. In this paper, Sharafat’s recursive contraction algorithm and cut-set decomposition method are symbolically implemented, and a novel symbolic algorithm for generating mechanical assembly sequences is presented using OBDD formulations of liaison graph and translation function. The algorithm has the following main procedures: choosing any one of vertices in the liaison graph G as seed vertex and scanning all connected subgraphs containing seed vertex by breadth first search; transforming the problem of enumerating all cut-sets in liaison graph into the problem of generating all the partitions: two subsets V1and V2of a set of vertices V where both the induced graph of vertices V1and V2are connected; checking the geometrical feasibility for each cut-set. Some applicable experiments show that the novel algorithm can generate feasible assembly sequences correctly and completely.

Assembly Model Based on Dynamic Transition Graph for Satellite General Assembly Process Planning

2012 ◽  
Vol 430-432 ◽  
pp. 1542-1545
Author(s):  
Gang Sun ◽  
Jian Feng Yu ◽  
Yuan Li
Keyword(s):  
Assembly Sequence Planning ◽  
General Assembly ◽  
Planning Problem ◽  
Assembly Process ◽  
Transition Graph ◽  
Dynamic Transition ◽  
Matrix Operations ◽  
Assembly Sequences ◽  
Mechanical Products ◽  
Cut Set

Beginning with the disassembly of the semi-finished modules, the general assembly process of satellites is quite different from that of other mechanical products. This kind of disassembly-reassembly process cannot be solved by the widely used cut-set theory that only deals with linear problems, thus an approach called Dynamic Transition Graph (DTG) is proposed to solve this nonlinear assembly sequence planning problem. By analyzing and verifying possible assembly statuses hierarchically through matrix operations, a DTG is produced on the basis of Liaison Graph, where the DTG includes all the geometric feasible assembly sequences for the general assembly of satellite. Finally, the effectiveness of this method is verified by an example.

scholarly journals Assembly Sequence Planning Using Artificial Neural Networks for Mechanical Parts Based on Selected Criteria

2021 ◽  
Vol 11 (21) ◽  
pp. 10414
Author(s):  
Marcin Suszyński ◽  
Katarzyna Peta
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Clustering Algorithm ◽  
Assembly Sequence Planning ◽  
Planning System ◽  
Assembly Sequence ◽  
Mechanical Parts ◽  
Sequence Planning ◽  
Assembly Sequences ◽  
Artificial Neural

The proposed model of the neural network describes the task of planning the assembly sequence on the basis of predicting the optimal assembly time of mechanical parts. In the proposed neural approach, the k-means clustering algorithm is used. In order to find the most effective network, 10,000 network models were made using various training methods, including the steepest descent method, the conjugate gradients method, and Broyden–Fletcher–Goldfarb–Shanno algorithm. Changes to network parameters also included the following activation functions: linear, logistic, tanh, exponential, and sine. The simulation results suggest that the neural predictor would be used as a predictor for the assembly sequence planning system. This paper discusses a new modeling scheme known as artificial neural networks, taking into account selected criteria for the evaluation of assembly sequences based on data that can be automatically downloaded from CAx systems.

A Dynamic Assembly Modeling Method for Satellite Final Assembly Sequence Planning

2010 ◽  
Vol 156-157 ◽  
pp. 332-338
Author(s):  
Yuan Zhang ◽  
Kai Fu Zhang ◽  
Jian Feng Yu ◽  
Lei Zhao
Keyword(s):  
Dynamic Model ◽  
Static Model ◽  
Modeling Method ◽  
Assembly Sequence Planning ◽  
Assembly Model ◽  
Assembly Sequence ◽  
Final Assembly ◽  
Model Tree ◽  
Assembly Sequences ◽  
Dynamic Assembly

To study the effect of assembly process information combining disassemble and assemble on satellite assembly sequence, this paper presents an object-oriented and assembly information integrated model, which is composed of static model and dynamic model. The feasibility determination based on Cut-set theory is presented and the construction algorithm of dynamic model is established by static model, the dynamic assembly model tree is obtained by analyzing in layers and verifying possible states using this algorithm, where the assembly model tree includes all the geometric feasible assembly sequences of satellite. Finally, this modeling method is verified by a satellite product.

A correct and complete algorithm for the generation of mechanical assembly sequences

1991 ◽  
Vol 7 (2) ◽  
pp. 228-240 ◽  
Author(s):  
L.S. Homem de Mello ◽  
A.C. Sanderson
Keyword(s):  
Mechanical Assembly ◽  
Assembly Sequences

Research on Aircraft Assembly Sequence Planning Technology Based on Key Characteristics

2013 ◽  
Vol 328 ◽  
pp. 9-16 ◽  
Author(s):  
Zhan Lei Sun ◽  
Peng Fei Han ◽  
Gang Zhao
Keyword(s):  
Process Design ◽  
Assembly Sequence Planning ◽  
Assembly Process ◽  
Assembly Sequence ◽  
Assembly Quality ◽  
Constraint Matrix ◽  
Aircraft Assembly ◽  
Sequence Planning ◽  
Key Characteristics ◽  
Assembly Sequences

Assembly Sequence Planning (ASP) is an essential question for aircraft assembly process design. Modern aircraft assembly contains plenty of complex shape components, which have so many assembly features to ensure, this leads to a large number of feasible assembly sequences using traditional sequence planning algorithms; and it is hard to evaluate the contribution to assembly quality for every sequence. A methodology called Key Characteristics Based ASP is proposed in this paper, which can significantly reduce unavailable sequences and ensure key features for quality in assembly process designing compared with previous methods. The methodology focuses on the final assembly quality and considers it as Assembly Key Characteristics (AKCs) in the beginning of assembly process design. With tools such as AKCs decomposition, Datum Flow Chain, precedence constraint matrix, the methodology describes the main process for ASP. To verify the technologys effectiveness, this paper presents an application of the algorithm in an aircraft component assembly by an 863 program.

Petri Net Models for Assembly Sequences Planning

2007 ◽  
Vol 10-12 ◽  
pp. 411-415 ◽  
Author(s):  
Y.L. Fu ◽  
R. Li ◽  
H.B. Feng ◽  
Y.L. Ma
Keyword(s):  
Petri Net ◽  
Assembly Sequence Planning ◽  
Assembly Model ◽  
Assembly Sequence ◽  
Assembly Operation ◽  
Knowledge Based ◽  
Assembly Sequences ◽  
Model Size ◽  
Assembly Sequences Planning ◽  
Optimal Assembly

Assembly sequences can be represented by a Petri net(PN) which characterizes dynamic system changes and provides a tool for obtaining optimal assembly sequences. In this study some assembly operation constraints are considered in order to obtain more practical sequences which are conformed to real situations. In order to enhancing the efficiency of the assembly sequence planning, knowledge-based Petri net, combining an usual Petri net with expert’s knowledge and experiences, is proposed to construct the assembly model. With the complexity of the product, the product’s assembly model size will be too large to analysis. So the basic subnets are used to reduce the large PN. And the reduced version can be used for the analysis of the original PN. To verify the validity and efficiency of the approach, a variety of assemblies including some complicated products from industry are tested, and the corresponding results are also presented.

AUTOMATIC COLLISION DETECTION FOR ASSEMBLY SEQUENCE PLANNING USING A THREE-DIMENSIONAL SOLID MODEL

2011 ◽  
Vol 10 (02) ◽  
pp. 277-291 ◽  
Author(s):  
ALFADHLANI ◽  
T. M. A. ARI SAMADHI ◽  
ANAS MA'RUF ◽  
ISA SETIASYAH TOHA
Keyword(s):  
Free Path ◽  
Collision Detection ◽  
Three Dimensional ◽  
Assembly Sequence Planning ◽  
Detection Methods ◽  
Assembly Sequence ◽  
Sequence Planning ◽  
Assembly Sequences ◽  
Geometrical Data ◽  
Selection Of

Assembly sequence planning of a product involves several steps, including generation of precedence constraints, generation of assembly sequences, and selection of assembly sequences. Generation and selection of assembly sequences should be able to guarantee the feasibility of assembly. Assembly will be feasible if there is no collision between components when assembled. Detection of collision-free path of assembly can be done in an automated way. There are a number of collision detection methods that have been developed, but the method requires a complicated process of data geometry analysis. This paper proposes a method for detecting a collision-free path of the assembly component in a more simple way. Geometrical data required, taken from the three-dimensional (3D) solid drawing in the form of stacked drawing in computer-aided design (CAD) systems. Retrieval of geometrical data of components and detection of the collision-free path of an assembly were done in an automated way, directly from the CAD system.

scholarly journals Automatically generating assembly sequences with an ontology-based approach

2019 ◽  
Vol 40 (2) ◽  
pp. 319-334 ◽  
Author(s):  
Yanru Zhong ◽  
Chaohao Jiang ◽  
Yuchu Qin ◽  
Guoyu Yang ◽  
Meifa Huang ◽  
...  
Keyword(s):  
Design Methodology ◽  
Feasible Solution ◽  
Automatic Generation ◽  
Great Difficulty ◽  
Assembly Sequence Planning ◽  
Assembly Sequence ◽  
Content Type ◽  
Sequence Generation ◽  
Assembly Sequences ◽  
Assembly Sequence Generation

Purpose The purpose of this paper is to present and develop an ontology-based approach for automatic generation of assembly sequences. Design/methodology/approach In this approach, an assembly sequence planning ontology is constructed to represent the structure and interrelationship of product geometry information and assembly process information. In the constructed ontology, certain reasoning rules are defined to describe the knowledge and experience. Based on the ontology with reasoning rules, the algorithm for automatically generating assembly sequences is designed and implemented. Findings The effectiveness of this approach is verified via applying it to generate the assembly sequences of a gear reducer. Originality/value The main contribution of the paper is presenting and developing an ontology-based approach for automatically generating assembly sequences. This approach can provide a feasible solution for the issue that mathematics-based assembly sequence generation approaches have great difficulty in explicitly representing assembly experience and knowledge.

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