The Integrated Optmization Problem Of Optimal Production Control And Production Capacity Planning Of Manufacturing Systems

In this paper, we investigate the integrated optimization problem of optimal production control and production capacity planning of manufacturing systems. We assume that the operational and failure time of the machines in the system follow the negative exponential distribution. A single product-type and single machine manufacturing systems, a serial production line with single product-type, and a multiple product types and multiple machines manufacturing system are analyzed, with the objective of minimizing the total production cost. According to the characteristics of each manufacturing system, we develop the corresponding optimization methods.For a single product-type and single machine manufacturing system, we develop a hedging point control policy with the production capacity regulation mechanism. When the demand changes over time in different ways, we develop the production optimization policy that decides how to adjust the production capacity according to the analytical relationship between the production capacity and hedging point policy. We also optimize the decision variables of the system, namely, the production capacity adjustment time and its quantity, by using the particle swarm optimization algorithm. Thus we obtain the integrated production control and capacity planning strategy for the system.For a serial production line with single product-type, the mathematical model of the integrated production control and capacity planning problem is constructed based on its structural characteristics. Considering the constraints of buffer sizes, and production rates of upstream and downstream machines, we develop the hedging point control policy with the regulation of production capacity. Under the given initial production capacity of the machine, the PSO algorithm are combined with the hedging point control policy to develop the integrated optimization strategy. The production capacity adjustment time and the capacity adjustment quantity are optimized by the particle swarm optimization (PSO) algorithm. Finally, we get the optimal control strategy system when the demand changes in different forms.For a multiple machines and multiple product-types manufacturing system, we first established the mathematical model of the integrated optimization of optimal production control and production capacity planning. We assigned priorities to each product type depending on their demands, based on which we present a kind of prioritized hedging point policy with production capacity regulation mechanism. For several kinds of demand forms, we use the PSO algorithm to optimize the decision variables of control strategy, i.e., the production capacity adjustment time and the capacity adjustment quantity. Then the corresponding optimization strategy of integrated production control and production capacity planning is proposed. Finally, simulation experiments are conducted by using Matlab for short and long production lines, to examine the effectiveness of the proposed optimization strategy.