Stable Assembly Sequence Planning Using a Genetic Algorithm

1999 ◽  
Author(s):  
Shiang-Fong Chen ◽  
Xiao-Yun Liao
Keyword(s):  
Genetic Algorithm ◽  
Simple Structure ◽  
Fitness Function ◽  
Assembly Sequence Planning ◽  
Connection Matrix ◽  
Assembly Sequence ◽  
Sequence Planning ◽  
Industry Standard ◽  
Planning Algorithm ◽  
The Stability

Abstract Stability problems in assembly sequence planning have drawn great research interest in recent years. Most proposed methodologies are based on graph theory and involve complex geometric and physical analyses. As a result, even for a simple structure, it is difficult to take all the criteria into account and to implement real world solutions. This paper uses a genetic algorithm (GA) to synthesize different criteria fo generating a stable assembl plan. Three matrices (Connection Matrix, Supporting Matrix, and Interference-Free Matrix) are generated from an input B-rep file to represent the CAD information of a given product. The stability of a given assembly plan and reorientation numbers are incorporated into the fitness function of the genetic assembly planner. The proposed planning algorithm has been successfull implemented. This paper also presents implemented planne performance as measured for two industry-standard structures.

A heuristic method with a novel stability concept to perform parallel assembly sequence planning by subassembly detection

2020 ◽  
Vol 40 (5) ◽  
pp. 779-787
Author(s):  
Anil Kumar Gulivindala ◽  
M.V.A. Raju Bahubalendruni ◽  
S.S. Vara Prasad Varupala ◽  
Sankaranarayanasamy K.
Keyword(s):  
Dominant Role ◽  
Heuristic Method ◽  
Development Stage ◽  
Assembly Sequence Planning ◽  
Assembly Sequence ◽  
Content Type ◽  
Sequence Planning ◽  
The Stability ◽  
Parallel Assembly ◽  
Stability Concept

Purpose Parallel assembly sequence planning (PASP) reduces the overall assembly effort and time at the product development stage. Methodological difficulties at framework development and computational issues at their implementation made the PASP complex to achieve. This paper aims to propose a novel stability concept for subassembly detection to minimize the complexities in PASP. Design/methodology/approach In this research, a heuristic method is developed to identify, represent and implement the stability predicate to perform subassembly detection and assembly sequence planning (ASP) at the further stages. Stability is organized into static, dynamic, enriched and no stability between the mating assembly parts. The combination of parts that possesses higher fitness is promoted to formulate the final solution about PASP. Findings The results obtained by applying the proposed concept on complex configurations revealed that stability predicate plays a dominant role in valid subassembly detection and final sequence generation further. Originality/value The value of the presented study lies in the three types of stability conditions and effective integration to existed ASP method. Unlike the existed heuristics in subassembly detection, the proposed concept identifies the parallel subassemblies during ASP.

Automated Microassembly Sequence Planning With Sub-Assemblies

2016 ◽  
Author(s):  
Joseph Seymour ◽  
David J. Cappelleri
Keyword(s):  
Fitness Function ◽  
Engineering Problem ◽  
Assembly Sequence Planning ◽  
Human Beings ◽  
Assembly Sequence ◽  
Test Bed ◽  
Sequence Planning ◽  
Macro Scale ◽  
Limited Degree ◽  
Feasible Solutions

Assembly sequence planning is an engineering problem that has been of great interest in the manufacturing field at the macro-scale. As more complex assemblies are desired at the micro and nano scales it is no longer feasible for human beings to plan and execute the production of these systems. A promising algorithm that allows optimization of assembly sequence plans that has been developed is called the Breakout Local Search. One drawback of this algorithm is its inability to consider the need for intermediate sub-assemblies to generate feasible solutions. Here an expansion to the BLS algorithm, called the Sub Assembly Generating BLS (SABLS) algorithm, is proposed. The fitness function of this new algorithm is also tailored to the specific constraints and motion primitives for a micromanipulation test-bed allowing for its use in microassembly applications. It is shown that the proposed algorithm is capable of generating optimized solutions that can be assembled with this limited degree of freedom system.

A Symbolic OBDD-Based Algorithm for Assembly Sequence Planning

2010 ◽  
Vol 97-101 ◽  
pp. 2444-2448
Author(s):  
Feng Ying Li ◽  
Tian Long Gu ◽  
Liang Chang
Keyword(s):  
Petri Nets ◽  
Petri Net ◽  
Assembly Sequence Planning ◽  
Decision Diagrams ◽  
Assembly Sequence ◽  
Binary Decision ◽  
Sequence Planning ◽  
Assembly Sequences ◽  
Planning Algorithm ◽  
The One

Algorithms based on timed Petri net are competitive for solving the problem of assembly sequence planning (ASP). In order to alleviate the state-space explosion problem which is caused by the Petri net-based representation of assembly sequences and to improve the efficiency of planning algorithms, an approach based on ordinary binary decision diagrams (OBDDs) is presented in this paper. On the one hand, all the timed transitions in Petri nets are substituted by some technically designed timed transition structures; on the other hand, Petri nets used in algorithms of assembly sequence planning are represented symbolically as OBDDs. As a result, a novel assembly sequence planning algorithm based on symbolic OBDDs is presented. With the help of OBDDs, both the marking vectors and the states of Petri nets are formulated more compactly; at the same time, the searching processes can be manipulated implicitly. Therefore, compared with original algorithms, both the time performance and the space performance are improved.

A hierarchical parallel multi-station assembly sequence planning method based on GA-DFLA

2020 ◽  
pp. 095440622097406
Author(s):  
Bo Wu ◽  
Peihang Lu ◽  
Jie Lu ◽  
Jinli Xu ◽  
Xiaogang Liu
Keyword(s):  
Hierarchical Structure ◽  
Assembly Line ◽  
Fitness Function ◽  
Information Matrix ◽  
Assembly Sequence Planning ◽  
Planning Method ◽  
Assembly Sequence ◽  
Cost Index ◽  
Sequence Planning ◽  
Structure Tree

In recent years, the parallel assembly sequence planning (PASP) is put forward to accommodate the development of greater variety in the mass-customization production. Although many researchers have made contributions to assembly sequence planning (ASP), how to construct parallel multi-station ASP model to effectively solve the integrated ASP and assembly line balancing (ALB) problem need to be further investigated. In this paper, a hierarchical parallel multi-station assembly sequence planning method based on the genetic algorithm and discrete frog leaping algorithm (GA-DFLA) is proposed to solve the integrated parallel multi-station ASP and ALB problem. The assembly information datasets of the model based definition (MBD) including parts information, hierarchical information, matrix information and resource information are defined firstly. Then the hierarchical structure tree is constructed according to the divided assembly units. The hierarchical parallel multi-station assembly sequence planning is carried out from bottom to top in hierarchical structure tree model using the GA-DFLA. The fitness function with feasibility index, time cost index and assembly line balance index, is proposed to determine a more appropriate solution. Finally, the rear independent suspension is taken as an example to validate this method. The results show that the time of parallel multi-station model is at least 35.27% less than the time of serial multi-station model.

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