On the uncertainties of decentralized controllers in a transfer productionline

In this paper, an information theoretic approach is applied to analyze the performance of a decentralized control system. The control system plays the role of a correcting device which decreases the uncertainties associated w ith state variables of a production line by applying an appropriate "correc ting signal" for each deviation from the target. In particular, a distribut ed feedback control policy is considered to govern a transfer production li ne, which consists of machines and buffers and processes a single part type in response to a stochastic demand. It is shown how the uncertainty of the demand propagates dynamically into the production system, causing uncertai nties associated with buffer levels and machine production rates. The paper proposes upper estimates for these uncertainties as functions of the deman d variance, parameters of the distributed controllers and some physical pro perties of the production line. The bounds are based on dynamic entropy mea sures of the system state and the control variables. Some practical implica tions into the area of decentralized controller design are proposed, an inf ormation-economical analysis is presented and a numerical study is performe d.