Fault-tolerant heterarchical control of heterogeneous manufacturing system entities

Abstract

Abstract This paper describes a new control architecture and a set of undelying design principles for developing and implementing fault-tolerant manufacturing systems consisting of Processing machines, robots, control computers and human operators. Significant innovations in the approach include the concept of “intelligent manufactured parts”, the use of a “flat” heterarchical architecture as opposed to the widely used hierarchical architecture, unification of simulation and control in system development and operation, integration of human as “colleagues” of other entities rather than “masters”, and achievement of implicit modifiability and fault-tolerance. An experimental heterarchically controlled manufacturing system has been developed in which robotic cells manipulat and manufacture parts. The system is comprised of independent robot, part processing, manufactured part, and human entities that cooperatively control the system through messages exchanged on a communication network. Successful design and implementation of the experimental system has shown that the approach presented in this paper has attractive properties that should be considered in future system designs, addressing a need for new system architectures and design philosophies that result in reduced complexity, higher fault tolerance, shorter development times, and lower development costs.