Generating finite-state global behavior of reconfigurable automation systems: DEVS approach

This paper introduces a method of achieving the finite-state global behavior of a reconfigurable automation system that consists of sub-components and which can be another component in a higher-level system. The approach introduced here is based on the discrete event system specification (DEVS) that has been regarded as a powerful simulation tool for modular and hierarchical systems, but its global states for whole behavior can be infinite. To achieve the finite state behavior that is needed for quantitative and qualitative analyses of a system, this paper introduces a new class of DEVS, called schedule-controllable DEVS (SC-DEVS) that can be seen as a middle class between the ordinary DEVS and schedule-preserved DEVS (SP-DEVS) that was proven that the global behavior of SP-DEVS networks can be abstracted in a finite number of states. The condition for finite-state space of SC-DEVS networks is addressed in the paper. In addition, the comparison between SC-DEVS and SP-DEVS in terms of the number of states and the time consumed in the generation procedure is illustrated by using a cluster tool example.