FLOWSHOP SCHEDULING DESIGN IN AN FMS MATRIX FRAMEWORK

Abstract

A systems theory point of view is used to develop a new matrix framework for controller design for the reentrant now-shop scheduling problem. The controller is comprised of outer and inner loops, where the inner loop is decision-free with no shared-resource problems. The outer loop involves shared-resources and so requires a conflict resolution command input u(c), selected based on dispatching rules. Matrices over a nonstandard (''and'', ''or'') algebra are used to describe the system structure, and the description of a new system with different part routings can quickly be obtained by changing only an operation sequencing matrix, S-up. The proposed controller is a rule-based structure that contains properties and behaviors of the shop-floor control portion of a manufacturing scheduling system. The proposed matrix framework allows rigorous analysis of the system leading to design for deadlock removal, and potentially for conflict resolution. The matrix formation can be used to confront schedule repair.