Research On Robust Control Of Dynamic Supply Chain Network Based On T-S Fuzzy Model

Supply chain management is a kind of important management model and has become a hot topic with rapid economic development. Supply chain management is crucial to enhance the competitiveness and efficiency of enterprises with the acceleration of global economic integration, and has been gradually concerned no matter academic point of view or economic point of view, supply chain is not only a simple supply chain no matter from the academic angel or from the economic angel analysis, and its complexity is mainly embodied in the supply and demand, and form a dynamic network structure. The network structure of this dynamic is lack of relative stability, the unstable factors not only influence the ability of the system which is responding to emergencies also limit the supply chain management level. At the same time, the system operation is subjected to lead times of interference in daily production, processing, distribution and sales, because of every participating enterprise in the whole supply chain network system with limitation of the economic and technology. The existence of lead time will often cause the oscillation of the system, and even lead to the instability of the whole system. The treatment effect is slightly less than the traditional control theory for the dynamic supply chain network system with various lead times and uncertainties. But fuzzy control theory with the characters that design simple, suitable for nonlinear system and strong robustness can effectively inhibit the internal and external uncertain factors in the process of system operation. Especially for the supply chain network system has better effectiveness for flexible operation, the promotion of flexible operation not only can improve the enterprise ability to respond to the change of the market demand and occupy the advantage in the fierce market competition. Therefore, this paper consider the customer demand, production lead time, ordering lead time, supply chain network structure, production cost, ordering cost and other internal and external uncertainty factors to establish three kinds of dynamic model of supply chain network respectively, and we give the robust control strategy with the application of fuzzy control theory to realize a robust operation of supply chain network dynamic system. The main works and contributions are embodied in the following aspects:(1) In order to suppress the impact on the supply chain network of uncertainties in the operation process, firstly, a discrete T-S fuzzy model of the dynamic supply chain network with uncertainties of the system parameters and the external demand is established. Secondly, a new fuzzy robust H∞control strategy is given, and this control strategy can not only effective reduce the large fluctuation among subsystems in the switching processes. but also ensure the supply chain network robust stably in uncertain environment. Finally, a simulation example is given to show the usefulness and effectiveness of the proposed control strategy.(2) The robust operation problem of a dynamic supply chain network with the production lead times and the ordering lead times is studied. Firstly, a discrete switched model of the dynamic supply chain network with lead times and the uncertain customer demand is established based on discrete T-S fuzzy systems. Secondly, by defining a discrete piecewise Lyapunov function in each maximal overlapped-rule group (MORG), a new fuzzy robust H∞control strategy for the dynamic supply chain network model is given through the method of the LMI. This control strategy can suppress the impacts of lead times and the uncertain customer demand on the operation of the dynamic supply chain network. Finally, a simulation example is proposed to illustrate the effectiveness of the proposed fuzzy robust control strategy.(3) The robust operation problem of an uncertain supply chain network with lead times is studied. Firstly, a discrete T-S fuzzy model of the uncertain supply chain network with lead times is constructed, which includes the uncertainties of production capacity, supply chain network structure, customer demand and the lead times. Secondly, by defining a discrete piecewise Lyapunov function in each MORG, a new fuzzy robust H∞control strategy for the supply chain network model is given, and the control strategy can suppress the impacts of uncertainties and lead times on the supply chain network, and ensure the supply chain network robust operation. Finally, a simulation example is given to show that the control strategy can make the total cost of the supply chain network reach the ideal state, which verifies the usefulness and effectiveness of the proposed strategy.