Robust Control Of Dynamic Supply Chain Considering Lead-time Compression

Time-based competition has gradually developed into a main competition mode among the enterprises,which reflected in the operation of the enterprise is the lead-time compression.Compressing the lead time can not only improve the competitiveness of the each node enterprise in the supply chain,but also response to customer demands faster.In addition,the supply chain system will be affected by internal and external factors of uncertainty in the process of operation,such as the uncertainties of the system parameters,the uncertainties of customer demands,and so on.The uncertain factors will cause the disturbances of the whole dynamic system,and even lead to the instabilities of the system operation.The fuzzy robust control method can suppress the system disturbances caused by the lead times and the various uncertain factors effectively,and realize the stable operation of the whole dynamic supply chain system.Thus,based on the above analyses,three models of the dynamic supply chain were constructed by considering the inventory levels of each node enterprise in the supply chain,the lead-time compression cost,the stock-out cost and various uncertain factors.Then,based on the comparison of the lead-time compression cost and the stock-out cost,a cost optimization strategy was proposed to reduce the total cost of the supply chain system,and a fuzzy robust control strategy was utilized to realize the stable operation of the supply chain system.The main research contents are as follows:(1)The robust operation of the dynamic supply chain system was studied by considering the lead-time compression.Firstly,a kind of quantitative model of the compressive cost and the compressive amount was established for the lead time,and then a cost optimization strategy was proposed by comparing the compressive cost with the stock-out cost under different inventory levels.Secondly,a fuzzy Takagi-Sugeno model of dynamic supply chain considering the lead-time compression was constructed,and a fuzzy robust control method was applied to realize the flexible switching among models.Finally,a simulation example of the dynamic supply chain was given to show that not only the total cost can be reduced but also the robust stability can be realized with the cost optimization strategy and the fuzzy robust control strategy.(2)The robust operation of the dynamic supply chain system was studied by considering lead times compression.Firstly,for the multiple lead times of production existed in the supply chain,a corresponding inventory state model and a total cost model of the supply chain were constructed based on the Takagi-Sugeno fuzzy control system.Then,through the Linear Matrix Inequality algorithm,a fuzzy robust control strategy for the dynamic supply chain model was proposed,which can suppress the impacts of lead times compression on the operation of the dynamic system and ensure the dynamic system robust stable operation.Finally,the simulation example show that the total cost of supply chain could be reduced effectively by the cost optimization strategy,and the steady operation of the supply chain system could be realized by the fuzzy robust control method.(3)The robust operation of the dynamic supply chain system was studied by considering lead times compression in an uncertain environment.Firstly,by considering the lead-time compression cost,the stock-out cost,the uncertainties of the system parameters,a fuzzy Takagi-Sugeno model of uncertain supply chain considering production lead times compression was constructed.Then,a fuzzy robust control strategy was proposed to suppress the influence of the uncertain factors and lead times on the dynamic supply chain system,and to realize the stable operation of the system.Finally,a simulation example was given to demonstrate the effectiveness of the cost optimization strategy and the fuzzy robust control strategy.