Research On Petri Net And Workflow Based Product Design Process Modeling

As a key stage of product producing, the product design stage plays an important role in dealing with the challenge of "TQCSE", for its high quality and efficiency not only can save the cost and the time of design effectively, but also can shorten the time of going on the market, reduce the cost taken by the producing and ensure the quality of products.The product design processes become more and more complex for the products becoming more and more complex, so the requirements can hardly be met just by engineering technology and the schematization of the process is needed. Therefore, basic research on product design process modeling is carried out, combining the product design process with workflow, in which the process planning acts as the basic research object and in which the Petri net modeling method is used. The research is committed to establish a reasonable and efficient product design process model to provide support for efficient product design. As a result, the following researches are carried out in the paper.(1) The research on task module dividing of the product design process. Firstly, as the minimum node of workflow modeling, task element is defined and the process forming a task element through task decomposition and adjustment is proposed; Then, a comprehensive correlation matrix among task element is set up; Following, initial modules are produced by the clustering method and the mathematical model of module partition optimization is built, based on which the optimization of module partition results is implemented by genetic algorithm.(2) The research on the design process modeling based on task planning. At first, the mission planning strategy is proposed, and task execution order planning based on DSM is presented; Then, based on the Petri net modeling method, a lot of element models for the basic task unit and for extended task unit, respectively, are built; Finally, on the basis of the strategies and methods put forward above, the workflow model of design process is researched.(3) The research on the task assignment of product design process. In the first of all, the design task evaluation system and candidate evaluation system are established; Then, the application of AHP and capacity equilibrium to the task allocation is researched; As well, a task allocation method based on improved fuzzy comprehensive evaluation is put forward; Based on the analysis of the advantages and disadvantages of each method, a strategy for executing task allocation is proposed.(4) Workflow modeling and Simulation of the product design process. First, a method based on WF net for the verification of the structure of a product design process model is proposed after researching the general method and workflow net method for verification of Petri net model; Then, the process verification and performance analysis of the process design model based on its simulation report is researched; Finaly, an example is proposed to show the modeling and simulation of its design process.