Distributed System-Level Control of Vehicles in a High-Performance Material Transfer System

In this paper, a fully-distributed system-level control architecture is described for dispatching, routing, and collision avoidance of multiple passive vehicles moving in a guideway network formed by a multitude of propulsion units. Propulsion units cooperate using a communication network with a topology identical to that of the guideway network, eliminating the need for explicit knowledge of global topography and enabling rapid real-time response to service requests using a parallel, shortest-route algorithm. The concepts developed are applied to a high-performance system in which vehicles respond to spontaneous requests to transfer material from point to point in manufacturing facilities in seconds rather than the minutes required in conventional AGV and conveyor systems. In this application, the vehicle and propulsion-unit lengths are on the same order of magnitude, the propulsion-unit-length/maximum-vehicle-velocity time characteristic is small, and the ratio of the number of propulsion units to the number of vehicles is large.