Research On Configuration Design Methods And Selection Of Reconfigurable Machine Tools

Reconfigurable Machine Tool(RMT)is a key part to support the implementation of the Reconfigurable Manufacturing System.The reconfigurability of RMT the core for manufacturing enterprises to realize the intelligentization of manufacturing process,and the importance to achieve RMT reconfiguration is the research of effective RMT design method and configuration selection.This paper focuses on the configuration design of RMT.Based on the in-depth study of RMT characteristics,it proposes a module-based RMT design method and configuration optimization.Where the basic theory and technologies such as processing parts,module selection,configuration generation and configuration optimization in the RMT design process are studied.First,in view of the feature of the processing parts,the operations faced by RMTs are identified,divided and grouped.Next,as for the given operational tasks,the required functions and structure of RMT are determined.These requirements are mapped to a series of mechanical modules and generate the feasible RMT configurations.According to the several indicators,the optimized scheme for RMT configuration design is selected from thethe generated feasible candidates.Finally,the proposed method is verified by the machining examples of the engine blocks.The content of this paper is as follows:(1)Grouping the Part Family for RMT Considering the Processing Features.This section mainly proposes a process demand feature model?part family,which is a process set of different parts within the same component family that can be processed on the same RMT.By constructing part families,the number of reconstructions can be effectively reduced and the processing efficiency can be guaranteed.By analyzing the characteristics of the operational requirements,the processing feature unit for parts is established to realize the formal expression of the processing features of the part.Based on the processing feature unit,a corresponding database for parts features was established to realize the mapping of processing features to the tool of RMT.Then,the Fuzzy cluster analysis was performed on the feature of the part and sorted according to the processing principles,which is to realize the reconstruction of the processing of the part family.(2)Designing the RMT Configuration Based on the part Family.Accordin to the requirements from part family,this section proposes a method for the generation of the RMT based on the configuration tree and polychromatic sets theory.In this method,the screw theory is used to transform the processingsinto the functional requirements of RMT,which also expresses the topological relations and execution order among the machine tools.Using the configuration tree,the basic functions required by the RMT are allocated to the structural configuration of the machine tool,so that the mapping relationship between the feature forming method and the RMT functional parts is established.The combination of tool components and workpiece-side components is implemented using the polychromatic set theory,and the RMT configuration schemes that met the requirements were generated.(3)Selecting the Optimized RMT Configuration Based on the the Multi-factor.This section analyzes three important indicators that influence the decision-making on RMT configuration,and establishes the index modeles for evaluation.Relying on the index models,a decision data table for slection of the optimized sceme is formed.The improved DEMATEL method based on rough set is used to analyze the three indexes of reconfigurability,cost,and error,while the weight values of the three indexes are obtained.Thereby,the candidate geometry set is ordered based on the VIKOR method to select the optimal scheme.(4)Example of the RMT Configuration Design and Selection.Using the machining examples of the engine block,the proposed RMT configuration design and selection methods were verified.There are the three steps for the RMT reconfiguration,requirement analysis,configuration design and configuration selection,respectively.In the configuration exploration,the design of RMT conforming to the feature change is performed for the reconstruction of the transformation between different parts of the same part family,and the feasible reconfiguration scheme are obtained.We apply the established RMT multi-objective decision-making method to select the optimal configuration scheme,which verifies the feasibility and effectiveness of the method.