An Automated Assembly Sequence Planing System for Mechanical Parts

Author(s):  
V. C. Sarvananthan ◽  
P. C. Pandey

Abstract This work provides a software system, which can automatically determine the assembly sequence of a product from its parts, given only a geometric description of the assembly. A simple closed envelope method for product geometry representation, and an efficient matrix method to represent contact and interference relations among the parts were successfully used in this work. The possible sub-assemblies are automatically detected by satisfying some mathematical conditions applicable to these matrices. Possible assembly sequences are generated for each sub-assembly and for the whole product. Furthermore, the algorithms are successfully examined with several industrial products.

2021 ◽  
Vol 11 (21) ◽  
pp. 10414
Author(s):  
Marcin Suszyński ◽  
Katarzyna Peta

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.


2021 ◽  
Vol 41 (5) ◽  
pp. 612-625
Author(s):  
Akram Bedeoui ◽  
Riadh Ben Hadj ◽  
Moncef Hammadi ◽  
Nizar Aifaoui

Purpose During the design of a new product, the generation of assembly sequences plans (ASPs) has become one of the most important problems taken into account by researchers. In fact, a good mounting order allows the time decrease of the assembly process which leads to the reduction of production costs. In this context, researchers developed several methods to generate and optimize ASP based on various criteria. Although this paper aims to improve the quality of ASP it is necessary to increase the number of criteria which must be taken into account when generating ASPs. Design/methodology/approach In this paper, an ASP generation approach, which is based on three main algorithms, is proposed. The first one generates a set of assembly sequences based on stability criteria. The obtained results are treated by the second algorithm which is based on assembly tools (ATs) workspace criterion. An illustrative example is used to explain the different steps of this proposed approach. Moreover, a comparative study is done to highlight its advantages. Findings The proposed algorithm verifies, for each assembly sequence, the minimal required workspace of used AT and eliminates the ASPs non-respecting this criterion. Finally, the remaining assembly sequences are treated by the third algorithm to reduce the AT change during the mounting operation. Originality/value The proposed approach introduces the concept of AT workspace to simulate and select ASPs that respect this criterion. The dynamic interference process allows the eventual collision detection between tool and component and avoids it. The proposed approach reduces the AT change during the mounting operations.


2010 ◽  
Vol 156-157 ◽  
pp. 332-338
Author(s):  
Yuan Zhang ◽  
Kai Fu Zhang ◽  
Jian Feng Yu ◽  
Lei Zhao

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.


2020 ◽  
Vol 40 (5) ◽  
Author(s):  
Hongjuan Yang ◽  
Jiwen Chen ◽  
Chen Wang ◽  
Jiajia Cui ◽  
Wensheng Wei

Purpose The implied assembly constraints of a computer-aided design (CAD) model (e.g. hierarchical constraints, geometric constraints and topological constraints) represent an important basis for product assembly sequence intelligent planning. Assembly prior knowledge contains factual assembly knowledge and experience assembly knowledge, which are important factors for assembly sequence intelligent planning. This paper aims to improve monotonous assembly sequence planning for a rigid product, intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge is proposed. Design/methodology/approach A spatio-temporal semantic assembly information model is established. The internal data of the CAD model are accessed to extract spatio-temporal semantic assembly information. The knowledge system for assembly sequence intelligent planning is built using an ontology model. The assembly sequence for the sub-assembly and assembly is generated via attribute retrieval and rule reasoning of spatio-temporal semantic knowledge. The optimal assembly sequence is achieved via a fuzzy comprehensive evaluation. Findings The proposed spatio-temporal semantic information model and knowledge system can simultaneously express CAD model knowledge and prior knowledge for intelligent planning of product assembly sequences. Attribute retrieval and rule reasoning of spatio-temporal semantic knowledge can be used to generate product assembly sequences. Practical implications The assembly sequence intelligent planning example of linear motor highlights the validity of intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge. Originality/value The spatio-temporal semantic information model and knowledge system are built to simultaneously express CAD model knowledge and assembly prior knowledge. The generation algorithm via attribute retrieval and rule reasoning of spatio-temporal semantic knowledge is given for intelligent planning of product assembly sequences in this paper. The proposed method is efficient because of the small search space.


Author(s):  
Shilpitha Bomi Reddy ◽  
Zahed Siddique

Efficient procedures for generation of feasible assembly sequences and effective utilization of available assembly plant resources can greatly reduce the development time and cost for platforms for the new product family members. This paper presents a method application to generate feasible assembly sequences and an approach to select an assembly process that reduces the existing plant modification cost. Assembly sequence design space is combinatorial in nature. Mathematical models to solve the effects of constraints on these spaces and algorithms to efficiently enumerate feasible spaces are presented. An algorithm that selects assembly process that can reduce the modification cost of the existing assembly plant is developed. A software application that implements the method and algorithms is also presented. The program uses the concept of recursive partitioning of set of components to generate assembly sequence space. The assembly processes are then evaluated to determine the process that maximized resource utilization. The application of the proposed approach and software is demonstrated using automotive underbody front structure product family.


2013 ◽  
Vol 328 ◽  
pp. 9-16 ◽  
Author(s):  
Zhan Lei Sun ◽  
Peng Fei Han ◽  
Gang Zhao

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.


Author(s):  
MVA Raju Bahubalendruni ◽  
Bibhuti Bhusan Biswal

Selection of optimized assembly sequence is significantly essential to achieve cost-effective manufacturing process. This paper presents a novel efficient methodology to generate cost-effective feasible robotic assembly sequences though concatenation of parts. Part concatenation process will be followed with liaison predicate test and feasibility predicate test. A unique method called bounding box method is described to test the feasibility predicate efficiently in the computer-aided design environment. Assembly indexing technique is proposed to filter the redundant assembly subsets with high energy in order to minimize the computational time. The cost of collision free assembling operation is considered by the weight and distance traveled by the part in the assembly environment to join with the mating part. The method is successful in finding feasible optimal assembly sequence without ignoring any possible assembly sequence and found to be efficient in solving computer-aided assembly sequence generation. The correctness of the methodology is illustrated with an example.


Robotica ◽  
1993 ◽  
Vol 11 (4) ◽  
pp. 351-362 ◽  
Author(s):  
D.Y. Cho ◽  
C.K. Shinf ◽  
H.S. Chot

SUMMARYThe consideration of part motion instability is crucial to the determination of assembly sequence since this affects the complexity of fixtures and dexterity of robots. This paper presents a new approach to the inference of robotic assembly sequences, taking into consideration the instability of base assembly motions. Based upon the evaluation of motion instability, the method generates stable assembly sequences by use of the precedence constraint inference method previously developed by the authors. An example assembly of a 10-part electrical relay is given to illustrate the concepts and procedure of the proposed scheme. The results show that the proposed method can be effectively utilized to generate stable assembly sequences, thus providing crucial information on the fixture design and selection of types of assembly robots.


2007 ◽  
Vol 10-12 ◽  
pp. 411-415 ◽  
Author(s):  
Y.L. Fu ◽  
R. Li ◽  
H.B. Feng ◽  
Y.L. Ma

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.


Author(s):  
C J Barnes ◽  
G E M Jared ◽  
K G Swift

An assembly-oriented design system has been developed which includes several analysis tools to improve product assemblability during product development. One of these tools supports the parallel development of the product design and the assembly sequence, thus exploiting the benefits of concurrent consideration of product and process. However, this approach requires some method for evaluating the sequence against requirements. Previous work on assembly sequence evaluation has concentrated on identifying the best from a set of ranked alternatives. When a single sequence is constructed, as with this tool, another method is needed. This paper reports the development of this novel methodology for evaluating individual assembly sequences. A review of the relevant literature has found several measures for identifying good assembly sequences from a ranked list and the fundamental sequence attributes extrapolated and aggregated. This leads to the proposal of four new indices: insertion index, stability index, difficulty index and complexity index. A large number of assembly sequences have been analysed to define limiting values for the indices such that they can quantify the potential of an incomplete sequence resulting in a satisfactory solution. The application of these indices in concurrent design and assembly planning is illustrated through an industrial case study.


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