On-line Monitoring of Plan Execution: a Distributed Approach

The paper introduces and formalizes a distributed approach for the model-based monitoring of the execution of a plan, where concurrent actions are carried on by a team of mobile robots in a partially observable environment. Each robot is monitored on-line by an agent that has the task of tracking all the possible evolutions both under nominal and faulty behavior of the robot and to estimate the belief state at each time instant. The strategy for deriving local solutions which are globally consistent is formalized. The distributed monitoring provides on-line feedback to a system supervisor which has to decide whether building a new plan as consequence of actions failure. The feasibility of the approach and the gain in the performance are shown by comparing experimental results of the proposed approach with a centralized one.