Research On Layout Design And Reconfiguration Technologies Base On Requirements Activation And Multi-domain Constraints For Complex Product

Layout scheme design is an important link in the process of complex product design.The shortcomings of existing methods are pointed out through reviewing the current research in requirement analysis and layout scheme design of complex product.In-depth research is carried out on the technique of implicit demand activation for complex products based on association constraints network,product layout design based on multi-domain demand constraints,layout reconfiguration based on spatial geometric error sensitivity,and multi-criteria fusion layout scheme evaluation based on group decision-making.The proposed methods are verified by design cases.The main contents of this paper are as follows:In Chapter 1:The research status and state-of-the-art are summarized.Research background,research content and the overall structure of the paper is introduced based on analysis of the shortcomings of the current design method of the complex products layout design.In Chapter 2:The requirements of customized products are divided into the explicit requirement,semi-implicit requirement and implicit requirement,and the association constraint networks of customized product requirements are established according to the different association constraints between requirements.By dynamic mapping of association constrained networks on matrices and calculation of the intensity of association constraints between requirement nodes,the custom product requirements association constraint matrix can be built.Hierarchical requirements of the custom product based on association constrained network including explicit,semi-implicit and implicit requirements can be activated thus providing complete customization requirement information for product design parameter in virtue of transferring of the intensity of associated constraints and cumulative requirement node activity.Taking the NC boring machine as an example,the application of implicit requirement activation for customized products based on the association constraint network is verified.In Chapter 3:The complex product layout design unit(LDU)is defined,and the method of disassembly and combination construction of LDU is proposed.The multi-granularity construction of LDU is realized.The multi-domain features of function domain,motion domain,shape domain and structure domain of layout design unit are established.The operation rules of feature association among layout design units and the calculation method of correlation strength among layout design units are proposed.The combination-pruning algorithm based on association features is adopted to solve the layout scheme of complex products.Taking the layout design process of typical complex product NC boring machine as an example,the method proposed in this chapter is applied and verified.In Chapter 4:The layout scheme reconstruction technology based on sensitivity analysis of geometric errors in workspace is studied.A multi-rigid-body geometric error model for complex products is constructed,and the screw mapping method in screw theory is applied to realize the screw expression of multi-rigid-body geometric error model.Through the sensitivity analysis of geometric errors in workspace of product layout scheme,the key layout design units affecting spatial geometric errors in complex product operation are determined.The vertical,horizontal and hybrid reconfiguration methods of complex product layout schemes are proposed,and the reconfiguration design process of complex product layout schemes based on workspace geometric error analysis is given.Taking the layout reconfiguration design of NC machine tools for typical complex products as an example,the feasibility of the method is verified.In Chapter 5:The uncertainties of multi-index evaluation weights and the difficulty of balanced evaluation in the reconfiguration evaluation of complex product layout schemes are studied.A multi-criteria fusion evaluation technology of complex product layout reconfiguration schemes based on group decision-making is proposed.The concept of similarity degree of layout design unit is put forward.Three evaluation criteria,namely,function chain similarity of layout unit,interface complexity of layout unit and reconstruction cost of layout scheme,are constructed.The corresponding quantitative calculation method is given.The importance of the evaluation index is estimated by a group analytic hierarchy process,and the layout reconstruction scheme is balanced by a multi-criteria optimization compromise analysis method.The balanced evaluation and optimization of layout reconstruction schemes are realized.In Chapter 6:The software architecture and development environment of demand-driven NC machine tool layout scheme design system is introduced.The specific functions and realization of the software system modules such as requirement analysis activation module,NC machine tool layout scheme design and reconstruction module,NC machine tool spatial error analysis module,NC machine tool layout scheme evaluation module and so on are explained.It is applied in the process of design requirement analysis,layout design and layout reconfiguration design of a vertical machining center.In Chapter 7:The organization and summarization of research results and the implications for future research are presented.