Distributed moving horizon state estimation with triggered communication

In this work, we consider communication cost reduction of distributed moving horizon estimation (DMHE) for a class of nonlinear systems. In particular, we focus on nonlinear systems that are composed of interacting subsystems which can communicate and exchange information with each other through a shared communication network. Specifically, an algorithm based on an event-triggered method is proposed to reduce the number of communications between the subsystems in a DMHE scheme. In the algorithm, a subsystem sends out its current information when a triggering condition based on the difference between the current state estimate and a previously transmitted one is satisfied. In order to ensure the convergence and ultimate boundedness of the estimation error, we also propose to redesign the local moving horizon estimator of a subsystem to account for the possible lack of state updates from other subsystems explicitly. A reactor-separator chemical process is utilized to demonstrate the applicability and performance of the proposed approaches.