engleski

Robust Event-Based Data Scheduling for Resource Constrained Networked Control Systems

This paper studies robustness of a recently proposed event-based scheduling design for multi-loop Networked Control Systems (NCSs) in which the control loops are coupled through a shared communication channel subject to limited capacity and uncertainties. The proposed scheduler combines deterministic and probabilistic attributes to efficiently allocate the channel access among the control loops in the presence of networked-induced phenomena such as packet dropouts and scheduling with delayed information update. Since the schedulers receive error information from a number of systems simultaneously, this sheer amount of information cannot always be processed in timely manner, which in turn gives rise to delays. Given the local error thresholds, our scheduler deterministically excludes subsystems with error values lower than their corresponding thresholds from the medium access competition in favor of those with larger errors. In case of resource scarcity, the scheduler probabilistically allocates the channel to the eligible systems (those that exceed the local threshold) according to an error-dependent priority measure. We show stochastic stability of such NCSs in terms of f-ergodicity of the overall network-induced error, which is modeled as a homogeneous Markov chain. Numerical results show stability of our proposed approach for NCSs of different sizes in presence of packet dropouts and delayed data update.

Networked control systems; Markov processes; Stochastic systems

nije evidentirano