Event-trigger Control of Discrete Two-time Scale System by Leveraging its Intrinsic Properties
01 Jun 2019-pp 3970-3975
TL;DR: This work proposes an event-trigger theory which leverages the physical property of discrete two-time scale system to reduce the requirement of network bandwidth.
Abstract: There are several physical systems which exhibit two-time scale property. When these systems are controlled through networks, uniform sampling causes an extra burden on the network bandwidth. Furthermore, uniform sampling of slow and fast variables leads to over-sampling of slow variables. This work proposes an event-trigger theory which leverages the physical property of discrete two-time scale system to reduce the requirement of network bandwidth. Events in slow and fast variables occur as per their respective dynamics and based on the occurrence of a respective event, only slow or fast variables are communicated through a network. Thus the communication of the state is carried out based on an event of the respective set of variables. Simulation studies are presented to validate the theoretical developments.
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TL;DR: This note investigates a simple event-triggered scheduler based on the paradigm that a real-time scheduler could be regarded as a feedback controller that decides which task is executed at any given instant and shows how it leads to guaranteed performance thus relaxing the more traditional periodic execution requirements.
Abstract: In this note, we revisit the problem of scheduling stabilizing control tasks on embedded processors. We start from the paradigm that a real-time scheduler could be regarded as a feedback controller that decides which task is executed at any given instant. This controller has for objective guaranteeing that (control unrelated) software tasks meet their deadlines and that stabilizing control tasks asymptotically stabilize the plant. We investigate a simple event-triggered scheduler based on this feedback paradigm and show how it leads to guaranteed performance thus relaxing the more traditional periodic execution requirements.
3,695 citations
"Event-trigger Control of Discrete T..." refers background in this paper
...Whenever the event condition is satisfied, information is transmitted which further update the control input [8]....
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...It was found that continuous ETM requires an additional hardware to know the triggering time instant of the event [8]....
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...In event-trigger mechanism, sampling takes place whenever some predefined condition is satisfied [8]....
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01 Dec 2012
TL;DR: An introduction to event- and self-triggered control systems where sensing and actuation is performed when needed and how these control strategies can be implemented using existing wireless communication technology is shown.
Abstract: Recent developments in computer and communication technologies have led to a new type of large-scale resource-constrained wireless embedded control systems. It is desirable in these systems to limit the sensor and control computation and/or communication to instances when the system needs attention. However, classical sampled-data control is based on performing sensing and actuation periodically rather than when the system needs attention. This paper provides an introduction to event- and self-triggered control systems where sensing and actuation is performed when needed. Event-triggered control is reactive and generates sensor sampling and control actuation when, for instance, the plant state deviates more than a certain threshold from a desired value. Self-triggered control, on the other hand, is proactive and computes the next sampling or actuation instance ahead of time. The basics of these control strategies are introduced together with a discussion on the differences between state feedback and output feedback for event-triggered control. It is also shown how event- and self-triggered control can be implemented using existing wireless communication technology. Some applications to wireless control in process industry are discussed as well.
1,642 citations
"Event-trigger Control of Discrete T..." refers background in this paper
...Various types of event-trigger mechanism have been proposed for the continuous system in [9], [10]....
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10 Dec 2013
TL;DR: The PETC strategies developed in this paper apply to both static state-feedback and dynamical output-based controllers, as well as to both centralized and decentralized (periodic) event-triggering conditions.
Abstract: Event-triggered control (ETC) is a control strategy that is especially suited for applications where communication resources are scarce. By updating and communicating sensor and actuator data only when needed for stability or performance purposes, ETC is capable of reducing the amount of communications, while still retaining a satisfactory closed-loop performance. In this paper, an ETC strategy is proposed by striking a balance between conventional periodic sampled-data control and ETC, leading to so-called periodic event-triggered control (PETC). In PETC, the event-triggering condition is verified periodically and at every sampling time it is decided whether or not to compute and to transmit new measurements and new control signals. The periodic character of the triggering conditions leads to various implementation benefits, including a minimum inter-event time of (at least) the sampling interval of the event-triggering condition. The PETC strategies developed in this paper apply to both static state-feedback and dynamical output-based controllers, as well as to both centralized and decentralized (periodic) event-triggering conditions. To analyze the stability and the L2-gain properties of the resulting PETC systems, three different approaches will be presented based on 1) impulsive systems, 2) piecewise linear systems, and 3) perturbed linear systems. Moreover, the advantages and disadvantages of each of the three approaches will be discussed and the developed theory will be illustrated using a numerical example.
1,011 citations
"Event-trigger Control of Discrete T..." refers background in this paper
...Various types of event-trigger mechanism have been proposed for the continuous system in [9], [10]....
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29 Jul 2010
TL;DR: In this paper, event-triggered strategies for control of discrete-time systems are proposed and analyzed and the overall framework is used in a novel Model Predictive Control approach.
Abstract: In this paper, event-triggered strategies for control of discrete-time systems are proposed and analyzed. Similarly to the continuous-time case, the plant is assumed input-to-state stable with respect to measurement errors and the control law is updated once a triggering condition involving the norm of a measurement error is violated. The results are also extended to a self-triggered formulation, where the next control updates are decided at the previous ones, thus relaxing the need for continuous monitoring of the measurement error. The overall framework is then used in a novel Model Predictive Control approach. The results are illustrated through simulated examples.
327 citations
"Event-trigger Control of Discrete T..." refers background in this paper
...Thus to avoid constant monitoring of the system, discrete event-trigger mechanism has been proposed [11]....
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...Eventtrigger composite control law (see [11]) can be obtained as u(k) = G1x1(t(1) k )+F1x2(t 2 k ) (9) where t1 k ∈ k and t2 k ∈ k....
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Book•
30 Jun 1988TL;DR: In this paper, the twin topics of singular perturbation methods and time scale analysis to problems in systems and control are discussed, and the heart of the book is the singularly perturbed optimal control systems which are notorious for demanding excessive computational costs.
Abstract: This book presents the twin topics of singular perturbation methods and time scale analysis to problems in systems and control. The heart of the book is the singularly perturbed optimal control systems, which are notorious for demanding excessive computational costs. The book addresses both continuous control systems (described by differential equations) and discrete control systems (characterised by difference equations).
182 citations
"Event-trigger Control of Discrete T..." refers background or methods in this paper
...Therefore there exists a similarity transformation T which is also a non-singular [1]....
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...However, time-scale strategy is broadly investigated in literature due to its two-time scale property [1], [2], [3]....
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...Assuming (Im − A22) to be non-singular, n and m dimensional decoupled subsystem can be deduced from (n+m) dimensional discrete system using a twostage transformation method (see [1]) or quasi steady state method [15], [2]....
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