Multiagent coordination for controlling complex and unstable manufacturing processes

We present a multiagent coordination technique to maintain throughput of a large-scale manufacturing system in the face of machine failures. Failures do not just deteriorate throughput of the system but also create and change bottlenecks in the system. Since loss of bottleneck’s capacity degrades the overall system performance, the system should identify bottlenecks dynamically and keep their utilization at a high level. In our system, CABS, information about a machine’s urgency of jobs to fulfill demanded throughput and maintain its utilization is passed to upstream machines in the product routes. Upstream machines utilize this information to identify bottleneck machines and coordinate their actions to provide the bottlenecks with necessary and sufficient jobs for preventing their starvation and congestion. We empirically evaluate CABS and show its effectiveness using a benchmark problem of the semiconductor fabrication process in comparison with CONWIP, which is a well-known traditional manufacturing control method.