Performance analysis for tandem manufacturing lines under variable structure production control method

In this paper we introduce novel results for the performance of the surplus-based decentralised production control method. The main objective of this production method is to guarantee that the cumulative number of produced products follows the cumulative production demand on the output of any given network. As a starting point of our research a general idea of this method is presented for the case of one manufacturing machine. Then our analysis is extended to a line of N machines. The proposed methodology is reformulated in terms of variable structure control. The production flow process is described by means of difference equations and, in order to analyse the performance, the Lyapunov theory approach is exploited. The results obtained for the production error bounds for each machine in the line and for the buffer content bounds for each intermediate buffer are discussed. Performance and robustness issues of closed-loop flow line models are illustrated by numerical simulations. It is shown that the method can be implemented in enterprise planning tools.