This note is concerned with event-triggered H∞ controller design for networked control systems. A novel event-triggering scheme is proposed, which has some advantages over some existing schemes. A delay system model for the analysis is firstly constructed by investigating the effect of the network transmission delay. Then, based on this model, criteria for stability with an H∞ norm bound and criteria for co-designing both the feedback gain and the trigger parameters are derived. These criteria are formulated in terms of linear matrix inequalities. Simulation results have shown that the proposed event-triggering scheme is superior to some existing event-triggering schemes in the literature.

A Delay System Method for Designing Event-Triggered Controllers of Networked Control Systems

http://www.ece.ualberta.ca/~tchen/papers/Gao_auto08n1.pdf

A new delay system approach to network-based control

This paper is concerned with the controller design of networked control systems (NCS). A new model of the NCSs is provided under consideration of both the network-induced delay and the data packet dropout in the transmission. In terms of the given model, a controller design method is proposed based on a delay-dependent approach. The feedback gain of a memoryless controller and the maximum allowable value of the network-induced delay can be derived by solving a set of linear matrix inequalities. Two examples are given to show the effectiveness of our method.

State feedback controller design of networked control systems

This paper investigates the problem of robust Hinfin estimation for uncertain systems subject to limited communication capacity The parameter uncertainty belongs to a given convex polytope and the communication limitations include measurement quantization, signal transmission delay, and data packet dropout, which appear typically in a network environment The problem of Hinfin filter design is first solved for a nominal system subject to the aforementioned information limitations, which is then extended to the uncertain case based on the notion of quadratic stability To further reduce the overdesign in the quadratic framework, this paper also proposes a parameter-dependent filter design procedure, which is much less conservative than the quadratic approach The quadratic and parameter-dependent approaches provide alternatives for designing robust Hinfin filters with different degrees of conservativeness and computational complexity Two examples, including a mass-spring system, are utilized to illustrate the design procedures proposed in this paper

${\cal H}_{\infty}$ Estimation for Uncertain Systems With Limited Communication Capacity

This note is concerned with stability and controller design of networked control systems (NCSs) with packet dropouts. New NCS models are provided considering both single- and multiple-packet transmissions. Both sensor-to-controller (S/C) and controller-to-actuator (C/A) packet dropouts are modeled and their history behavior is described by different independent Markov chains. In term of the given models, sufficient conditions for stochastic stability are derived in the form of linear matrix inequalities (LMIs) and corresponding control laws are given. Numerical examples illustrate the effectiveness of the results.

Design of Networked Control Systems With Packet Dropouts

Brief Networked control design for linear systems

Brief Further results on localization-based switching adaptive control

Brief Stability and switching control design issues for a class of discrete time hybrid systems

Many different types of adaptive or universal controllers", capable of dealing with a very broad range of linear time-invariant systems, have been proposed. One class of such controllers uses switching between a finite, or at least countable, number of fixed controllers until stability is detected. Such controllers are very attractive from a theoretical viewpoint, in providing stabilization and asymptotic performance for a broad class of plants. However, such controllers are also known to have very poor transient properties, due to the long time required to search for a stabilizing feedback. The key contribution of this paper is to introduce the "method of localization" which can greatly improve the speed of the search. The method is described for linear time-invariant discrete time systems of known nominal order, with disturbances and noise present. Analysis and simulations demonstrate the potential for greatly improved transient performance.

Localization based switching adaptive controllers

This chapter presents a new systematic switching control approach to adaptive stabilization of uncertain discrete-time systems. The approach is based on a method of localization that is conceptually different from supervisory adaptive control schemes and other existing switching control schemes. The proposed approach allows for slow parameter drifting, infrequent large parameter jumps, and unknown bound on exogenous disturbances. The unique feature of the localization-based switching adaptive control, proposed in the chapter, is its rapid model falsification capability. In the LTI case this is manifested in the ability of the switching controller to quickly converge to a suitable stabilizing controller. It is believed that the approach is applicable to a wide class of linear time invariant and time-varying systems with good transient performance.

Peter V. Zhivoglyadov

Papers

Brief Networked control design for linear systems

Brief Further results on localization-based switching adaptive control

Brief Stability and switching control design issues for a class of discrete time hybrid systems

Localization based switching adaptive controllers

Adaptive stabilization of uncertain discrete-time systems via switching control: The method of localization