Research On The Key Technology Of Collaborative Design For Complex Product Based On Meta-Synthesis

The design of complex product, in which the multidisciplinary cooperative design model is usually used, is involved with knowledge of different levels, different fields and different types. Improving the design efficiency is of great significance to the national security and economic sustainable development, due to the important application of complex product in defense and military field, as well as in national economy field. Meta-synthesis is an effective method proposed by Chinese scientists, to deal with the problems of complex system. Hall for workshop of meta-synthetic engineering (HWME) is application form of meta-synthesis, and it's essentially an integration of expert system, machine system and knowledge system, which combines the different discipline theory with the experience and knowledge of human, to deal with the problems related to complex system.Based on the design of large-scale weapon system and process plant, this paper researches on the model and method of improving the efficiency of collaborative design for complex product, using meta-synthesis. HWME of collaborative design for complex product is constructed, with multiple functions e.g. group argumentation, project management, collaborative decision and 3-d visualization, to provide the design experts full process and unified collaborative platform. The design experts in different places could perform design activities in parallel. At key stages, with this HWME, they schedule the design task, share design information, make group discussion, make decision for relative problems, check or modify the design result collaboratively, which could help to shorten the design period, improve the design quality and reduce design cost. First, based on meta-synthesis, the process model and the general framework of collaborative design for complex product are established. Then, the key technology is researched, including analysis of consensus in the filed of group argumentation, task scheduling in the filed of project management, system synthesis in the filed of collaborative decision,3-d review in the filed of 3-d visualization. Finally, a prototype system of HWME is developed. Some specific contributions are as follows:1. A process model and a general framework of collaborative design for complex product based on meta-synthesisEstablishing the process model and expressing the design process effectively is the foundation of collaborative design. According to the features of design process for complex product, a multi-level process model of collaborative design for complex product based on the dimensions of time, particle size and parallelism is established, combining with meta-synthesis. This process model emphasizes on the combinations of multi-stage in time dimension, combinations of multi-specialty in parallelism dimension and iteration of decomposition and integration in particle dimension. Then, on the based of the process model, a general framework of collaborative design for complex product based on meta-synthesis is proposed, combining with expert system, knowledge system and machinery system. Machinery system helps the expert group with knowledge from knowledge system. Expert system fulfill the collaborative design process of combinations of human-computer, multi-specialty and multi-stage, with the services provided by machinery system, e.g. project management, group argumentation, collaborative decision and 3-d visualization.2. A method for analyzing consensus to support group argumentationIf the experts understand current consensus state, the efficiency of the group argument can be improved. So a method for analyzing consensus based on cloud model and evidence theory is proposed, with respect to the characteristics of divergent argument in HWME, such as continuity, fuzziness and complexity. Firstly, this method uses cloud model to acquire the opinion implicated in every comment, according to the semantic relations between argument information. Then synthesizes the implicated opinions expressed by an expert in all time into the expert opinion on the base of evidence theory. And at last, obtains qualitative distribution map of expert opinion and quantitative level of consensus and attention, in accordance with acquired opinions from different experts. Examples indicated that the consensus state could be analyzed effectively using this method, which could help to reach consensus.3. A hybrid method of qualitative and quantitative analysis for design task schedulingDesign task scheduling is of great significance to collaborative design for complex product, both in terms of time and quality. To solve the task scheduling problem in collaborative design for complex product, a qualitative and quantitative model is established, and a strategy to estimate design task time based on case-based reasoning is proposed, and a strategy to solve the model based on genetic algorithms is proposed. By introducing tacit knowledge of the subject and object, this model synthesizes the impact of qualitative indexes and quantitative indexes on collaborative design. Based on the information of the design task which has been finished by design unit before, the estimating strategy improves the rationality of time estimation for task design. The solving strategy can guarantee the completeness of search space, and obtain the optimal solution of the model rapidly under the constraints of tasks. Finally, a detailed example is given to confirm this method, which can be used to shorten the design period and improve the design quality.4. A human-computer combination method for system synthesisSystem synthesis is essentially a decision process for combinatorial optimization. To solve the problems of system synthesis in collaborative design for complex product, a human-computer combination method for system synthesis is proposed. Firstly, an evaluation index system is established on the base of AHP method, from qualitative to quantitative. Then scheme selection is carried out in many times of iteration based on interactive genetic algorithm, with the comprehensive evaluation combining of qualitative and quantitative analysis as its fitness. Finally, a detailed example is given to confirm this method. It proves that this method can be used to improve the efficiency of system synthesis greatly.5. An improved method of computer supported 3-d review for multi-specialtyReview is essentially a process of conflict detection and conflict resolution. The 3-d review can make the reviewer feeling realistic while checking the design results, which improves the detection rate of design errors and design conflicts. It also can carry out automatic or semi-automatic review by the strong computing capability of the computer, which reduce the reviewer's working strength and shorten the review time. However, in the 3-d review for multi-specialty, there're contradictions between the heterogeneous information with large quantities, various categories and the computers with limited performance. In order to perform 3-d review for multi-specialty on an ordinary PC, an information model combined scene tree and attribute tree is proposed, and a multi-resolution rendering approach of large-scale process plant models based on programmable graphics pipeline is proposed. The information model could organize the information from different CAD systems with a unified structure, also could optimize the query speed of information. The multi-resolution rendering approach could ensure real-time interaction in large-scale and complex scene without extra hard-disk space, with little loss in image quality, while less preprocessing time is required. An example indicates that this method is effective and practical.