Research On Automatic Generation Of Assembly Sequence Of Shin Block

Assembly sequence planning is that analyzing and fetching the design and assembly information of product to generate geometry feasible assembly sequence, and then according to the relevant evaluation index to evaluate, finally the optimal assembly sequence can be acquired. As for shipbuilding that is a vast and complex systematic project, block assembly is a very important process, and the stand or fall of assembly sequence will have a significant impact on the efficiency and quality of the final block. Therefore, there exists important practical significance in assembly sequence planning of the hull block. This article selects a typical double bottom block as the object of study to carry out the research of assembly sequence planning.Firstly, on the basis of analyzing the connection relationship between all components of the block, the article uses the thought of network diagram in engineering management, then draws the disassembly network diagram according to constraint relations between the various parts in the process of disassembly, at last assembly information model is established. In order to facilitate subsequent computer processing, disassembly interference matrix will is generated on the basis of disassembly network diagram according to certain rules, and program is written using VB to analyze and process the interference matrix, and to generate the disassembly sequence.Secondly, based on the reversal disassembly method, namely "if it can be disassemblied then it can be assemblied", assembly sequence is the opposite sequence of the disassembly sequence. In the case of multiple parts in the same assembly sequence, the analytic hierarchy process (AHP) is applied to evaluate the main factors that affecting the assembly sequence (such as:the quality of components, component assembly length, etc.) and assign weight factors, and the score of each component can be acquired. Then for components in the same assembly sequence according to the score, final assembly sequence will be acquired respectively under parallel and serial assembly method, and the assembly process information table will be output in the form of Excel spreadsheet table.Then, by applying the secondary development of DELMIA software, automatic simulation of block assembly process can be realized. Taking the assembly process information table generated in front as basic information, the program drives DELMIA to automatically insert3d block model established in CATIA into the list of product model in PPR tree, to create process for the assembly activities of each component in the list of assembly process, and to simulate the assembly process according to front assembly sequence in DPM virtual assembly environment, then to record the assembly process and generate animation video, providing reference for assembly sequence evaluation.Finally, taking assembly efficiency, cost, quality and difficulty as the evaluation index, the article establishes two-level fuzzy comprehensive evaluation model for block assembly sequence, applies the factor paired comparison method to get the weight vector of each evaluation index, and establish fuzzy relation matrix according to the statistical result of expert opinion. At last, the total score can be calculated by weighted average method, and the result shows that the evaluation level of assembly sequence is "good".