Research On Technologies And Applications Of Modular Design In The Mechanical System Based On Function-Principle-Behavior-Structure Design Theory

To respond rapidly to the various requirements of mechanical equipments, the modular design methodology and technology are introduced in the process of conceptual design of mechanical products. The technology of product modular design based on Function-Principle-Behavior-Structure (FPBS) is one of the key solutions to meet the requirements. Several aspects including product conceptual design, product module identifying and module creation, product family planning and design, product configuration design, module adaptive/variant design, and module reconfiguration design are deeply discussed. The main achievements are described as follows:(1) The modeling method based on function-structure (FS) independence and behavior compatibility is brought forward. As to the complexity of conceptual design of mechanical system(product), several steps are taken according to the objective features of products. Firstly, function-principle mapping, principle-structure solution and structure-function decomposition in the process of product conceptual design are realized by means of the iterative vertical design of FPBS. At the same time, according to the axiomatic design theory and the behavior compatibility principle, the decoupling of functions and structures of a product is carried out. Once the basic FS units have relative independent structures, functions and compatible behaviors, the FPBS decomposition model of product is established. Secondly, the method combining IDEFO with function flow modeling is applied to product function modeling, behavior correlation is applied to product principle modeling, assembly joining is also applied to product structure modeling, and accordingly the horizontal dynamic models of product design are established. Based on the above, the topology model of conceptual design for mechanical products and the modular design method are integrated. So the modular design method based on the model of product conceptual design is presented.(2) The methods of module identifying and creation of products based on FPBS design model are advanced. As to module creation, the correlative analysis of the product's FS elements (function, behavior, structure, interface, etc.) is spread to create correlation computation model of FS units based on the FPBS design model of product. Afterwards, the fuzzy clustering algorithm is used to perform a bottom-up polymerization for FS units. Finally hierarchical module identifying and module creation for the product are realized.(3) The methods for product family planning and design are brought forth based on FPBS design model of the product to creat module system. Firstly, the product family that satisfies market subdivision is constructed through cluster analysis of the customer requirements. Considering the quantitative change and the qualitative change of product's performance parameters, the FPBS decomposition is outspread from functions of the product family. Thereby the FS units of different hierarchies are set up. At the same time, feature parameters and their ranges of the product family's FS units are determined by means of the Quality Function Deployment (QFD) method. Secondly, the function model of bottom FS units for FPBS decomposition of product family is set up. FS modules of different levels of product family are built using pedigree clustering, and the basic FS modules and extended FS modules are determined. Accordingly, the basic module family and extended module family are set up by the synthesis of structures and characteristic parameters of FS units, thus the product family planning is achieved.(4) The methods of product extension configuration design based on the module system of product family are put forward. Directed towards rapid product design based on the module system, serveral approaches are carried out for customer requirements based on product family model. In the first place, expectant product features are spread hierarchically using waterfall decomposition method of QFD, while product configuration solution is performed using the method based on knowledge inference, as a result, the matter-elements of expectant module are obtained. In the next place, grounded on this, similar existent modules are elicited from module family using the similarity matching algorithm. Consequently, preliminary configuration plan is formed. Then, through ISM analysis, transformation structure hierarchies and transformation requirements of similar existing modules are determined, and extension transformation is carried out. Eventually the plan of product structure is gained.(5) The methods of extensive module adaptive design/variant design based on the model of FPBS design are proposed. Focused on the variant design of a single module, the FPBS decomposition model of the existing module is established firstly, and through extensive transformation and decomposition of functions, principles, behavior, and structures of the module, the FPBS design model of expectant module is created. Secondly, the function model of expectant module is built. Then based on the constraints of the function model, the adaptive design/variant design of the module is realized through the deletion and polymerization of the structure units and through the conduction transformation analysis in extensive transformation, decomposition, and polymerization of the module's FS elements.(6) The methods of module reconfiguration based on FPBS design model are given. As to the reconfiguration design of several modules, the FPBS design model of existing modules is established. Based on the above models, function reconfiguration by function flow joining, principle configuration by behavior transmitting, behavior combination by behavior coincidence, and structure polymerization by behavior compatibility are carried out. Thus, the design models of expectant module are constituted, and the module reconfiguration design is achieved through the structural synthesis and design of the expected modules.(7) The computer aided Modular Design Support System (MDSS) is developed to satisfy the engineering applications of modular design method. The system is designed and developed based on the research achievements of the thesis. The system runs on common CAD platforms and follows the common procedures of product modular design. Therefore the engineering application for the modular design method of mechanical system based on FPBS is accomplished primarily.