A control structure for multi-tasking workstations

Manufacturing control modules, which are bascd on hierarchical control theory, decompose commands from a supervisory controller into elementary tasks to be performed by subordinate systems. The ability to simultaneously manage coordinated and independent functions of subordinates, while also processing new commands from the supervisory controller, i s beneficial in advanced implementations of these controllers. T h i s paper describes a control structure, based on computer operating system principles, which provides the desired capabilities. Utilizing concurrent processing and coordinating tasks via resource allocation provides extensive modularity which simplifies integration. gives a multi-processing environment, and produces the aforementioned capabilities.