A DISTRIBUTED MODEL OF CONCURRENCY FOR ROBOT
Sensorimotor Synchronization, V.G. Kountouris, Harry E. Stephanou · 1990
The exploitation of the task-executing versatility of nonconventional robot systems is clearly more demanding than the conventional industrial robotic applications. While the latter applications are limited to a single manipulator executing repeatedly a single preprogrammed task in a well-structured environment, the former requires a sensor-based robot system and more elaborate techniques for (i) task decomposition and robot modularization, (ii) task distribution to robots and sensors, and (iii) the dynamic specification of the distributed semantics involved in handling the redundancy of kinematic chains and the multiplicity of agents. In this paper, we develop an algebra of Petri nets for the dynamic specification of the distributed semantics of task synchronization in hierarchical multiagent systems. More specifically, the proposed algebra allows for the hierarchical specification of the flow of control and the temporal order of task execution by multiagent systems. Each level of the resulting hierarchies horizontally contains the synchronization-structure of task execution and vertically is a generalization of the level below and a specialization of the level above. We show that the horizontal synchronization-structures developed by the proposed Petri net model maintain the desirable properties of safeness and liveness by construction.