Preview

PDF, English Download (552kB) | Terms of use

Abstract

A nested monitoring, diagnosis and reconfiguration (MDR) scheme is proposed for a Recursive Nested Behavior based Control structure (RNBC)constituting a generic system architecture for (semi-) autonomous mobile systems. Each behavior layer within the RNBC structure is associated with a MDR schema, which is responsible to ensure the dependability of every single layer. An online dependability measurement and diagnosis procedure is integrated into monitor and diagnosis blocks under consideration of performance and safety acceptability factors. The reconfiguration blocks within the MDR-scheme switch from components with unacceptable behavior to redundant components, which may have degraded performance but more robust and safe behavior. The MDR blocks at each layer are nested through unified interfaces in order to utilize the distributed modeling of system behavior and to facilitate the system design and implementation process. In a small case study the MDR scheme is demonstrated for an assistant wheelchair on the body velocity control and axis velocity control levels. Simulation results show the feasibility and effectiveness of the approach.