On-line monitoring and diagnosis of a team of service robots: A model-based approach

The paper presents an approach for the on-line monitoring and diagnosis of multi-robot systems where services are provided by a team of robots and the environment is only partially observable via a net of fixed sensors. This kind of systems exhibits complex dynamics where weakly predictable interactions among robots may occur. To face this problem, a model-based approach is adopted: in particular, the paper discusses how to build a system model by aggregating a convenient set of basic system components, which are modeled via communicating automata. Since the dynamics of a multi-robot system depend on the actions performed by the robots (and actions change over time), the global system model is partitioned into a number of submodels, each one describing the dynamics of a single action. The paper introduces the architecture of the Supervisor which has to track the actions progress and to infer an explanation when an action is completed with delay or fails. The Supervisor includes two main modules: the On-line Monitoring Module (OMM) tracks the status of the system by exploiting the (partial) observations provided by sensors and robots. When the monitor detects failures in the actions execution, the Diagnostic Interpretation Module (DIM) is triggered for explaining the failure in terms of faults in the robots and/or troublesome interactions among them. The RoboCare domain has been selected as a test bed of the approach. The paper discusses experimental results collected in such a domain with particular focus on the competence and the efficiency of both the OMM and the DIM.