Research On The Life Cycle Management Of Task-driven Virtual Enterprise

This work is supported by Natural Science Foundation of China (NSFC-60474077) and Program for New Century Excellent Talents in University (NCET-05-0653). Taking task-driven as a. clue, adopting multi-agent theory, game theory and particle swarm optimization (PSO) algorithm integratedly, this dissertation focuses on the study of three key issues of life cycle management of virtual enterprise, which are partner selection, production task scheduling and information sharing. The main contents are as follows.First, this dissertation analyzes the process of life cycle management of task-driven virtual enterprises and its key problems. On the basis of expaining the meanings of life cycle management of task-driven virtual enterprise, a corresponding relationship figure between each task phase and each life cycle phase is established, and then the life cycle management process of task-driven virtual enterprise is briefly described. Thereafter, the focuses are paid on the difficulty analysis on problems' solution of partner selection, production task scheduling and information sharing. The analysis points out that the difficulty of the partner selection mainly embodied in selection decision-making, in negotiating and contracting, and in coordination management; the difficulty of production task scheduling mainly reflected in tasks scheduling optimization and in corresponding cooperation process; the difficulty of information sharing mainly embodied in establishment of the information-sharing platform, in the design of mechanisms and in the choice of strategies when dealing with information sharing.Second, this dissertation presents a partner selection structure model for task-driven virtual enterprises and proposes a corresponding partner selection optimization algorithm. The partner selection structure model of task-driven virtual enterprise is proposed based on multi-agent technology. As for optimization problem on partner selection, based on minimizing costs within the time constraints, the study proposes a partner selection model to solve optimization problem of partner selection. Using restriction method, this optimization problem for partner selection is proved to be a NP-complete problem. To find the solution of this optimization problem, an improved PSO algorithm is proposed which includes initial enlargement, variance and local updating process. Utilizing three processes synthetically improves the optimization effect of PSO algorithm. Two examples of partner selection for agile manufacturing are presented to illustrate and prove the applicability of the presented model on partner selection in virtual enterprise and the validity of the proposed optimization algorithm.Third, a model of production task scheduling in virtual enterprises is presented and a corresponding scheduling optimization algorithm is proposed. The hierarchy structure model on task scheduling includes virtual enterprise layer and partner layer. As for scheduling optimization problem, a model for minimizing manufacturing cycle is built, in which some key factors in virtual enterprise layer are considered, such as time sequence and logic relationship among production tasks, operation timing and partner's own production tasks, however, some key factors in partner layer are considered, such as resource possessing, transportation time and so on, and the PSO algorithm is proposed. A large-scale equipment manufacturing case is presented to illustrate and prove validity of the presented production task scheduling model and the proposed optimization algorithm.Fourth, a game model of information sharing of virtual enterprises is proposed and strategies and methods for improving high-level information sharing are presented. Take a virtual enterprise which is made up of a leader enterprise and a partner enterprise as research object, the game model of information sharing is established and "the prisoner's dilemma" of information sharing is put forward. In the prisoner's dilemma of information sharing, both the leader and the partner try to increase their own profit through sharing lower information with its counterpart, so the result comes out that the profit of the virtual enterprise and of each partner's decrease and high-level information sharing is impracticable. To achieve high-level information sharing, solutions are presented both for single and repeated game. For single game, an incentive mechanism design method is presented which combines the auction and punishment mechanism, while for repeated game, a method based on game learning, strategy adjustment and increasing game times is presented. The following simulation proves that the methods are effective.Finally, based on the mentioned research achievements, a prototype system is established, what's more, a case of the R&D and manufacture of 300-tons automobile crane is presented to prove the feasibility, validity and applicability of the mentioned research conclusions.