Order release and deadlock avoidance interactions in counter-flow system optimization

Supervisory controllers for automated manufacturing systems must assure good system performance and guarantee deadlock-free operation. Order release mechanisms are performance control policies that order and schedule the release of work into the system, while deadlock avoidance policies are control policies that inhibit enabled events that might lead to deadlock. Because neither policy explicitly considers the objectives of the other, their decisions often conflict. To guarantee continuing system operation, these conflicts must be resolved in favour of the deadlock avoidance policy, and as a result, the intended beneficial effects of the order release mechanism can be significantly undermined. The goals of this paper are: (i) to demonstrate how deadlock avoidance and order release can be integrated to form a control policy that ensures continued system operation and improved performance with regard to performance measures; and (ii) to experimentally investigate the important interactions that can arise between these two types of control. 1999 Taylor & Francis Group, LLC.

Order release and deadlock avoidance interactions in counter-flow system optimization Academic Article