Hybrid FMS control architectures based on holonic principles

The escalation in processor technologies and the corresponding reduction in costs have enabled alternative FMS control architectures to be developed without the restrictions of “fixed machine controller boundaries”. These new architectures can be based upon the use of intelligent servo axes, which are desccribed in this article, as flexible numerical control (FNC). In current parlance, the FNC is a “part movement holon” within a manufacturing cell. The control architectures that can be derived from the FNC concept are referred to as hybrid architectures and share the emerging attributes of holonics. This article details the problems that arise in the scheduling and control of FMSs in the light of hybrid control architectures. A number of traditional scheduling approaches have been devised to cope with the scheduling of parts to discrete machines, but the problem here is to ascribe the processing (machining) of part features to axis groups. This article documents how two research programs, undertaken at the CIM Centre at Swinburne University of Technology in Hawthorn, Victoria, Australia, have endeavored to address the problem of hybrid architectures and their associated scheduling.