In: Journal of Robotic Systems, Vol. 12, No. 3, pages 177-187. 1995.
Abstract: This article presents a Petri net-based approach to modeling and evaluating four different deadlock avoidance schemes for a distributed robotic system, i.e., a five-robot-five-assembly-line system. Among these four schemes are the conventional, full synchronization, global semaphore, and partial synchronization schemes. To explore such issues as the system performance and control structure complexity, this article conducts detailed Petri net modeling for this system and evaluates performance of the deadlock avoidance schemes using stochastic Petri nets. The interesting results presented include that: (1) any possible system deadlock can seriously degrade the system performance even if effective deadlock resolution techniques are available; (2) conservative use of resources is likely to be the best policy; and (3) higher resource utilization may not necessarily imply higher system production rate in a resource-sharing environment. The related results need to be further explored for the larger resource-sharing discrete event systems.
Keywords: Petri nets, deadlock avoidance, distributed systems, robotic systems.