Papers by Author: Li Hong Qiao

Abstract: Model-based definition (MBD) promises reduced time-to-market and improved product quality. Adopting MBD concept in product development process seems to be the next reasonable step. However, some existent critical issues related to data content and presentation need to be overcome. To offer proper solutions from the standpoint of design and manufacturing integration, MBD concept was firstly introduced in order to describe its characteristics and capabilities. Then the answers to the following questions were given: what data are necessary for design and manufacturing integration, how data should be semantically organized and presented based on solid model and CATIA PPR (Product Process & Resource) tree.

Abstract: In the manufacture process of many large-scaled and complex products assembly, due to large number of parts or components, assemblies are often divided into several small assembly units in order to organize production and increase assembly efficiency. To obtain fine-grained rapid assembly unit partition, this paper presents a method of assembly unit partition based on cut-set theory with consideration of the assembly constraints and assembly complexity. The paper also discusses the method of establishing the assembly relationship graph of a product as the basis of unit partition. The relationship graph is extracted from the CAD model of the product and is used to describe the relationship of its component assembly. Using the proposed unit partition method, assembly constraints such as precedence relationship can be considered so that invalid assembly unit partition will be avoided. Furthermore, by defining assembly complexity, optimal selection of assembly unit partition can be achieved. The procedures of assembly unit partition including establishing of assembly relationship from CAD model, approach to cut-set, optimal selection and validation are addressed with an assembly example and a flow chart.

Abstract: In a product structure composed of different parts, sub-assemblies and/or assemblies, different constituents have their particular role in overall product function. Modular product design enables designing instances of a product suitable for different applications with minor design changes in certain parts or systems and plays an important role in product customization. On the other hand, product geometry and functional parameters are related with each other and appropriate selection of the former can ensure fulfillment of the latter. In this research, a micro-level methodology for product customization by designing part instances in a modular design is presented. The approach emphasizes on achieving product functional parameters while controlling respective critical geometric parameters. In this regard, product geometric and functional parameters relationships are established using regression analysis of results from finite element analysis (FEA) simulations of product process model. The research is applied on a machine structure from industry and the results show success and effectiveness of the proposed methodology.

Abstract: One of the major barriers to the integration of CAD, CAPP and CAM is insufficiency and incompatibility of product model data among various application systems. This paper presented an effective approach to achieve integrated process planning with CAD and CAM under a product data management environment based on 3D product models. The system architecture and the processes of an integrated process planning system (3D-IPP) were constructed using feature information and specific CAD/CAPP/CAM integration technologies based on feature. A feature-based product information model is designed as the information source for the 3D-IPP. A feature-based integrated process planning method was developed based on group technology, intelligent decision-making algorithms and parametric operation templates in numerically controlled (NC) programming. The procedures of intelligent process route planning and parametric NC operation planning were addressed. The 3D-IPP system and its implementation provide an effective solution to strive for complete information sharing among application systems of CAD, CAPP and CAM.

Abstract: The production organized in flexible manufacturing cells (FMC) can be a complicated issue when they are constrained by machines, robots, equipment and some other resources. Since machines and robots are the main bottleneck to the efficiency of FMC, this paper focused on the modeling and scheduling problem constrained by machines and robots. A common model representation, colored timed Petri net (CTPN) was utilized to build a FMC model constrained by robots and machines, which was then transformed to the simulation model. The scheduling problem was studied to establish a mathematical model of the FMC constrained by machines and robots. According to the model, a genetic algorithm was proposed to search an optimal solution by using an indirect coding of scheme. The effectiveness of the proposed algorithm was validated via an instance and the comparison with the result from the solution of simulated annealing algorithm.

Abstract: An agile data service framework was proposed in the paper to meet the requirement of agile manufacturing data management in product lifecycle management. The framework was comprised of four layers: core object and ontology layer, meta-data and meta-mode layer, service component layer and implementation layer. The realization of agile manufacturing data management was investigated through the analysis of the unified manufacturing data modeling and the implementation based on services. The descriptive structure and the main content of the manufacturing data model was given. The architecture of the manufacturing data management system based on services was addressed to conduct service implementation of the framework. The proposed approach of agile data services brought forward a new feasible solution to agile data management throughout product lifecycle.

Abstract: A scheduling approach using genetic algorithms (GA) was presented to optimize multiple projects for quality project period performance with resource constraints. The model of the approach and key parameters of the algorithm including chromosome encoding and decoding, fitness computation, initial population, selection and crossover were conducted. A precedence feasible list was used in the chromosome encoding and decoding operation to reduce search space. An efficient crossover method was developed to avoid the procedure of chromosome recovery. A comparison was made between the algorithm and a heuristic scheduling method with an example. The result validates the superiority of the approach.