DYNAMICS AND CONTROL OF INTEGRATED PRODUCTION INVENTORY-SHIPPING SYSTEMS.

Abstract

Multivariable system theory is used to synthesize piecewise constant control policies for production-inventory systems which incorporate unfilled-order backlogs. The state variables of the systems are the actual production rate, the inventory level discrepancy and the unfilled-order backlog respectively. The control inputs are the desired production rate and the desired shipping rate, and the disturbance input is the demand for finished parts. It is shown that the original multi-imput system can be decoupled into a set of single-input sub-systems in the modal domain by using a suitably chosen generalised modal matrix. The required policies for the original system are then readily obtained by considering each of the decoupled sub-systems separately. The behavior of the controlled production-inventory system is illustrated by the presentation of the results of computer simulation studies.