Zhang Wenan

Stabilization of networked control systems with communication constraints

This paper is concerned with the stabilization problem for a class of networked control systems with communication constraints. State feedback controllers are considered and the resulting closed-loop NCS is modeled as a discrete-time switched system. By using the asynchronous dynamical systems approach and the average dwell time method, sufficient conditions for the exponential stability of the closed-loop NCS are derived in terms of matrix inequalities. A design procedure is also presented for the stabilizing controllers. Finally an illustrative example is given to demonstrate the effectiveness of the proposed method.

A switched system approach to networked control systems with time-varying delays

The stabilization problem is studied for the networked control systems with time-varying delay that is smaller than one sampling period. State feedback controllers are considered and a new switched system model is proposed to describe the resulting closed-loop NCS as a discrete-time switched system. Criteria of exponential stability for the closed-loop NCS and design procedures for the stabilizing controllers are presented by using the average dwell time method. An illustrative example is given to show the effectiveness of the proposed method.

Modelling and Control of Networked Control Systems with Random Packet Losses

The modelling and control problems are studied for a class of networked control systems (NCSs) with both network-induced delays and random packet losses. The packet-loss processes in the forward channel and the backward channel are modelled as two Markov chains. The state feedback control law is considered, and the resulting closed-loop system is a discrete-time Markovian linear system with two modes. Mean-square exponential stability conditions are derived for the closed-loop NCS by using a properly constructed Lyapunov function. Corresponding state feedback controllers design procedures are also presented based upon the stability conditions. Finally, an illustrative example is given to demonstrate the effectiveness of the proposed method.

Constrained consensuses in disconnected topologies

This paper is concerned with the constrained consensuses problem for a group of agents in disconnected topologies. By dividing the communication topology into a combination of directed trees, some necessary and sufficient conditions are derived for all the agents to asymptotically reach a single consensus and multiple consensuses, respectively. The obtained results indicate that arbitrary anticipant consensuses can be achieved, if additional constrained controllers are added to those agents with specific indexes. Some illustrative examples are provided to demonstrate the effectiveness of the proposed theoretical results.