Bullwhip Effect In Supply Chain Modeling And Control

Since has entered the 21st century, the market globalization and the service division of labor more and more refinement, the market competition gradually evolved from competitions between pure enterprises to those between the supply chains. The supply chain management can reduce the enterprise's production cost, increases the enterprise's profit. As a new pattern in modern business management, it has aroused the multitudinous scholar's interest. It is at present studies a hot spot to conduct the supply chain management research from the control angle including the management, the model, the system, the control and so on many domains. Supply chain having the multiplicity, the internal nodes having the complex connection, customer demand being unknown, all enable the question of supply chain modeling to become the difficulty to study at present. In this article, we use the method which unified by qualitative and the quota synthesized the theories of economic, management science and cybernetics and so on and study bullwhip effect which is the variance amplification of order qualities in supply chains with emphasis. In view of the control theory in two kind of models-transfer function and the state space equation, we study separately how to carry on the appraisal and control bullwhip effect in supply chain management under these two models in this article.In the third chapter, we have studied how to establish the supply chain model and qualify the bullwhip effect. In the production networks, there exists the question of the product production cycle and it is discrete while in the retail network it is continuous to deal with material handling and information handling. In view of the production and the retailing networks' characteristics, we use state block diagram to simulate the bullwhip effect in supply chains. Through the simulation, we transfer the supply chain into the transfer function model and the state space model that are familiar in the control theory field. In the fourth chapter, we choose a simple supply chain model based on exponential smoothing forecasts as the study object. We first simulated the PID control model in MATLAB/Simulink and then acquired the variables in PID control using the genetic algorithm and carried on PID control that is usually applied in industrial field to the bullwhip effect model established in the third chapter.In the fifth chapter, we choose a multi-layered production stock time-lag discrete state space model as the study object. We applied the robust H∞control method to the bullwhip effect in a supply and obtained a good result.In this article the approaches of PID control and robust H∞control are used in the control of bullwhip effect in supply chains and all make good performance. The methods in this article make a good suggestion to how to apply control theory into the supply chain management.The article finally has carried on the summary to the research content, and proposes several tentative plans to further research work.