An event-based online scheduling approach for networked embedded control systems

In networked embedded control systems (NECSs) where a number of independent control loops are closed over a shared communication network, guaranteeing a stable behavior of the closed-loop trajectories with some level of performance through a suitable optimal control law is an essential objective. Relying only on the controller while neglecting the switching mechanism between the associated control loops may lead to a deficient control performance. Joint design of a control law and an offline/online scheduling law can improve the control performance significantly. Using either offline scheduling or online scheduling, however, may not achieve the best reachable performance. Therefore, an event-based online scheduling approach, jointly with a control design, is proposed in this paper to improve the resulting performance. The main idea is to balance between offline scheduling and online scheduling such that the advantages of each are preserved. The proposed codesign strategy is formulated as an LMI optimization problem and evaluated through simulating a networked embedded control of a set of inverted pendulums. Notably, the proposed theory is also generally applicable to discrete-time switched linear systems.