Structural Active Object Systems for Manufacturing Control

A structural active object system SAOS is a transition-based object-oriented system suitable for the design of various concurrent systems. A SAOS consists of a collection of interacting structural active objects SAOs whose behaviors are determined by the transition statements provided in their class definitions. We can compose SAOs structurally and hierarchically from their component SAOs. These features allow SAOs to model components in manufacturing systems more naturally than passive objects used in ordinary object-oriented programming. Because the configuration of a SAOS can be made similar to a real manufacturing system, the SAOS model can be used throughout the lifecycle of a manufacturing system, including the design, control software implementation, simulation, test, and operation stages. In fact, a composite SAO can be automatically generated from the computer-aided design data that specifies the configuration of the hardware subsystem with which the SAO is associated. Prototype simulation programs with graphical user interfaces have been developed as SAOSs for flow-line manufacturing and flexible manufacturing.