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Sampled-data Systems (sampled-data + system)

Distribution by Scientific Domains

Engineering	90%

Selected Abstracts

Internal stabilization of standard sampled-data systems

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003
B. P. Lampe Prof. Dr.
The paper presents necessary and sufficient conditions under which for a standard sampled-data system there exists a digital controller, that ensures the internal stability of the system. For the case of stabilizability a general expression for the set of all stabilizing controllers is given. The stabilizability conditions are formulated as divisibility of certain polynomials, controllability and observability concepts are not used. [source]

Sampled-data H, control for networked systems with random packet dropouts,

ASIAN JOURNAL OF CONTROL, Issue 4 2010
Xiaosheng Fang
Abstract This paper is concerned with the H, control problem for networked control systems (NCSs) with random packet dropouts. The NCS is modeled as a sampled-data system which involves a continuous plant, a digital controller, an event-driven holder and network channels. In this model, two types of packet dropouts in the sensor-to-controller (S/C) side and controller-to-actuator (C/A) side are both considered, and are described by two mutually independent stochastic variables satisfying the Bernoulli binary distribution. By applying an input/output delay approach, the sampled-data NCS is transformed into a continuous time-delay system with stochastic parameters. An observer-based control scheme is designed such that the closed-loop NCS is stochastically exponentially mean-square stable and the prescribed H, disturbance attenuation level is also achieved. The controller design problem is transformed into a feasibility problem for a set of linear matrix inequalities (LMIs). A numerical example is given to illustrate the effectiveness of the proposed design method. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

H2 -OPTIMAL SAMPLED-DATA CONTROL FOR PLANTS WITH MULTIPLE INPUT AND OUTPUT DELAYS

ASIAN JOURNAL OF CONTROL, Issue 2 2006
Konstantin Yu.
ABSTRACT The sampled-data H2 -optimization problem for plants with multiple input and output delays is considered. An equivalent discrete-time system is constructed and numerical algorithm for computing matrices of its state-space realization is presented. It is proved that stability of this system is equivalent to stability of original sampled-data system. The proposed method can be applied to a wide class of digital control problems for continuous-time plants with multiple input and output delays. [source]

Guaranteed Cost Sampled-Data Control for Refining Process

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2001
Yingquan Lu
This paper presents a synthetic design procedure of guaranteed cost sampled-data control (GCSDC) for refining process. When a digital controller controls the refining process with appropriate sample and hold devices, the closed loop system is periodic time varying. Based on this sampled-data system, considering the uncertainties in the continuous-time plant, we define the guaranteed cost control and a controller that not only stabilizes the closed loop system but also guarantees an adequate level of the performance. Simulation results show that the control scheme is effective and practicable. [source]

Exploring the maximum capability of adaptive feedback

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2002
Lei Guo
Abstract The main purpose of adaptive feedback is to deal with dynamical systems with internal and/or external uncertainties, by using the on-line observed information. Thus, a fundamental problem in adaptive control is to understand the maximum capability (and limits) of adaptive feedback. This paper gives a survey of some basic ideas and results developed recently in this direction, for several typical classes of uncertain dynamical systems including parametric and non-parametric non-linear systems, sampled-data systems and time-varying systems. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Tracking control for sampled-data systems with uncertain time-varying sampling intervals and delays

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2010
N. van de Wouw
Abstract In this paper, a solution to the approximate tracking problem of sampled-data systems with uncertain, time-varying sampling intervals and delays is presented. Such time-varying sampling intervals and delays can typically occur in the field of networked control systems. The uncertain, time-varying sampling and network delays cause inexact feedforward, which induces a perturbation on the tracking error dynamics, for which a model is presented in this paper. Sufficient conditions for the input-to-state stability (ISS) of the tracking error dynamics with respect to this perturbation are given. Hereto, two analysis approaches are developed: a discrete-time approach and an approach in terms of delay impulsive differential equations. These ISS results provide bounds on the steady-state tracking error as a function of the plant properties, the control design and the network properties. Moreover, it is shown that feedforward preview can significantly improve the tracking performance and an online extremum seeking (nonlinear programming) algorithm is proposed to online estimate the optimal preview time. The results are illustrated on a mechanical motion control example showing the effectiveness of the proposed strategy and providing insight into the differences and commonalities between the two analysis approaches. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Network-based H, control for stochastic systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 3 2009
Xiangyu Meng
Abstract This paper investigates the problem of network-based control for stochastic plants. A new model of stochastic time-delay systems is presented where both network-induced delays and packet dropouts are taken into consideration for a sampled-data network-based control system. This model consists of two successive delay components in the state, and we solve the network-based H, control problem based on this model by a new stochastic delay system approach. The controller design for the sampled-data systems is carried out in terms of linear matrix inequalities. Finally, we illustrate the methodology by applying these results to an air vehicle control problem. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Constrained robust sampled-data control for nonlinear uncertain systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2002
Li-Sheng Hu
Abstract In industrial process control, computer control, which makes the closed-loop system a sampled-data one containing both continuous- and discrete-time signals, is widely used. In contrast with traditional approximation methods, sampled-data synthesis, a direct digital controller design procedure without approximation, has received increasing attention during the past few years. However, many of the existing results cannot be applied to sampled-data control design for the uncertain systems. In this paper, a result of robust asymptotic stability of sampled-data systems with constraints on the state is presented based on a result on practical stability for these systems. Then the robust sampled-data control for a class of uncertain nonlinear systems with constraints on the output is developed. The problem is formulated from vehicle steering control with constraint on the side slip angle of body. The result is described by some matrix inequalities which could be solved by an iterative algorithm based on the linear matrix inequality technique. Finally, a numerical example is presented to demonstrate the result. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Internal stabilization of standard sampled-data systems

SYSTEMS WITH NONEQUIDISTANT SAMPLING: CONTROLLABLE?

ASIAN JOURNAL OF CONTROL, Issue 4 2005
OBSERVABLE?
ABSTRACT Some qualitative properties of systems with nonequidistant sampling are investigated. First, it is proved that the nonequidistant sampling pattern mentioned in [1] does not affect the controllability and observability of time-varying linear systems during discretization. The result is claimed to be true for linear systems with periodic behavior and time-varying sampling. Second, closed-loop stability conditions are established, respectively, for linear and nonlinear sampled-data systems consisting of continuous plants and linear digital feedback controllers. The stability results are extended to general systems consisting of nonlinear continuous plants and nonlinear digital controllers with time-varying sampling periods. [source]