Embedding machining features in function blocks for distributed process planning

Abstract

IEC 61499 function blocks, being emerging industrial process measurement and control standards, are chosen as data processing and execution control elements within the context of a distributed process planning (DPP) system. A two-layer structure, consisting of supervisory planning (SP) and operation planning (OP), is identified to separate the generic process data from those machine-specific ones. Within DPP, function blocks are used for data encapsulation, machining parameter optimization, process monitoring, scheduling integration, and CNC control. From SP to OP, a function block evolves from meta function block, through object function block, to execution function block. The detailed design of a meta function block is depicted in this paper. A function block designer has been developed to help process planners define basic function block types and generate composite function block networks. It is expected that the function block-enabled DPP approach and the associated algorithms can largely improve the dynamism of process plans as well as the flexibility and productivity of job shop operations in a changing environment.