Chengen Wang

Systematically managing product models and their derivative data becomes a rudimentary and essential requirement for manufacturing companies to cost-effectively develop and operate complex product systems. It is recognized that conventional product data management techniques are deficient in information integration across disciplinary boundaries and product lifecycle stages. Increasing complexity in product developments demands all related aspects be dealt in accordance with systems engineering methodologies. In compliance with the prevailing model-based systems engineering (MBSE) methodology, this paper proposes to extend conventional product data management to product lifecycle model management (PLMM), which shift emphasis from data managements to model managements throughout a whole product lifecycle. This paper first presents a MBSE-compliant PLMM architecture that outlines the related methodology, modeling techniques, processes, knowledge management, etc. Then, this paper describes basic compositions of a generic PLMM software platform that materializes the PLMM approaches. Subsequently, this paper reports a joint PLMM research initiative in China. It is anticipated that manufacturing companies will benefit much from implementations of PLMM techniques.

An assembly sequence planning (ASP) method that combined the advantages of ant colony system (ACS) and Max-Min ant system (MMAS) is proposed. To identify the best sequence easily, five optimization criterions are automatically quantified, including reorientation, parallelism, continuity, stability and auxiliary stroke, and then integrated into the multi-objective heuristic and fitness functions of ant colony optimization (ACO). To improve the search capability for the global-best sequence, several measures are presented from aspects of determining number of ant, max-min pheromone limits, performance appraisal for initial components allocation and the group method for same components. The ASP algorithm based on Max-Min ant colony system (MMACS) is proposed. An assembly planning system AutoAssem is developed based on Siemens NX platform, and the actual effectiveness of each optimization measure is testified through case study of a valve.

One of the tasks in assembly planning is to create the exploded views for the visualization purpose and the verification of assembly plans. In this paper, we introduce how to generate exploded views automatically from an assembly model. To increase the level of automation, a new relational matrix called extended interference matrix (EIM) is used to represent the assembly relations among constitutive parts. Information in an EIM is used to create the exploded views. An innovative method is developed to generate the exploded views based on the assembly sequences and EIMs. The corresponding Application Programming Interface (API) to the Unigraphics software has been developed as an integration of the algorithm with the CAD software tool. The assembly model of a gear reducer is used as a case study.

In the assembly modeling of complex products, it is not unusual facing an explosive growth of assembly relations, or called combination explosion. Through integrating object-oriented methods with the knowledge template based modeling, in this paper, a new methodology is proposed to deal with the complexity of the assemblies of large-scale products. As such, the templates with various assembly relations can be defined for complex products; constitutive parts or subassemblies in a product structure are defined as object classes; their features can be encapsulated, and defined or modified freely via the parameters of object classes to meet the requirements of a specific instance. The new method supports reusing knowledge and simplifying assembly modeling of complex products. In this paper, recent literatures on object-oriented methodologies and knowledge template methods for assembly modeling are reviewed, the rationales of object-oriented templates are discussed, and a method is proposed for creating assembly templates for complex products. In the case study included in this paper, the developed method has been applied to digital modeling of aero-engines, thus, validating its performance.