A distributed architecture and negotiation protocol for scheduling in manufacturing systems

Abstract

This paper deals with a new architecture and negotiation protocol for the dynamic scheduling of Manufacturing Systems. The architecture is based on two paradigms: Multi-Agent Systems and Holonic Systems. The main contribution in the architecture is the development of Holons representing tasks and resources. The well-known Contract Net Protocol [R. Davis, R. Smith, Negotiation as a metaphor for distributed problem solving, Artificial Intelligence, 20, (1), (1983) 63–109] has been adapted to handle temporal constraints and to deal with scheduling conflicts. The purpose of this protocol is to dynamically assign operations to the resources of the Manufacturing System to accomplish the proposed tasks. This protocol involves a renegotiation phase whenever exceptions appear. It also deals with conflict situations, namely, with the case of the `indecision problem'. The used approach assumes that deadlines are the most important constraints to consider. Thus the acceptance or refusal of a resource for a specific operation depends on the capability of executing the operation within the specified deadline.