Reduced-order synthesis of operation sequences

Abstract

In flexible manufacturing systems a large number of operations need to be coordinated and supervised to avoid blocking and deadlock situations. The synthesis of such supervisors soon becomes unmanageable for industrial manufacturing systems, due to state space explosion. In this paper we therefore develop some reduction principles for a recently presented model based on self-contained operations and sequences of operations. First sequential operation behaviors are identified and related operation models are simplified into one model. Then local transitions without interaction with other operation models are removed. This reduction principle is applied to a synthesis of nonblocking operation sequences, where collisions among moving devices are guaranteed to be avoided by a flexible booking process. The number of states in the synthesis procedure and the computation time is reduced dramatically by the suggested reduction principle.

Abstractions for nonblocking supervisory control of Extended Finite Automata

“…Effective and consistent model abstraction is accomplished through transition projections with the observer property. A special case of this abstraction, including additional structural reduction, has been applied on a large-scale manufacturing workcell [18], where more than 98% of the computational time and space has been saved.…”

Supervisory control of extended finite automata using transition projection

“…A manufacturing workcell example demonstrates the computational effectiveness and practical usage of the proposed approach. A special case of this abstraction, including additional structural reduction, has been applied on a large-scale manufacturing workcell [30], where more than 98% of the computational time and space has been saved.…”