Adaptive Event-triggered Communication Scheme Research Articles

Observer‐based event‐triggered security control for nonlinear networked control systems with cyber attacks

SummaryThis paper investigates the observer‐based security control problem for interval type‐2 nonlinear networked control systems with deception attacks and replay attacks. Firstly, to alleviate the communication burden of the network, a novel adaptive event‐triggered communication (ETC) mechanism is proposed. Compared with existing observer‐based adaptive ETC security control techniques, the threshold of the proposed adaptive ETC scheme can be adjusted dynamically depending on the value of adjustable parameters and estimation error. In particular, the adjustable parameters can change the sensitivity of the threshold flexibly. Then, taking the influence of the adaptive ETC mechanism and cyber attacks into consideration, an observer‐based security controller is developed under the co‐designed method. Furthermore, by utilizing the Lyapunov stability theory, sufficient conditions for asymptotically mean‐square stable of the closed‐loop system are obtained. Ultimately, the feasibility of the designed control approach can be proved via a simulation example.

Adaptive H∞ event-triggered load frequency control in islanded microgirds with limited spinning reserve constraints

Using an islanded microgrid (MG) with large-scale integration of renewable energy is the most popular way of solving the reliable power supply problem for remote areas and critical electrical users. However, compared with traditional power systems, the limited spinning reserves and network communication bandwidth may cause weak frequency stability in the presence of stochastic renewable active outputs and load demand fluctuations. In this paper, an adaptive event-triggered control (ETC) strategy for a load frequency control (LFC) system in an islanded MG is proposed. First, a bounded adaptive event-triggered communication scheme is designed. This not only saves on network resources, but also ensures that the control center has a sensitive monitoring ability for the MG operating status when the frequency deviations have been effectively damped. Secondly, by fully considering the spinning reserve constraints and uncertain communication delays, the LFC system is described as a nonlinear model with saturation terms. Design criteria for ETC parameters are strictly deduced based on Lyapunov stability theory. Finally, an ETC parameter optimization algorithm based on random direction search is developed to reconcile the bandwidth occupancy and control performance. The effectiveness of the proposed method is verified in an MG test system.

Adaptive event-triggered group consensus of multi-agent systems under stochastic sampling

This paper investigates group consensus for linear multi-agent systems with nonidentical dynamics. A novel adaptive event-triggered communication scheme is presented by using the stochastic sampling information, the event-triggered matrices and time-varying event-triggered parameters are introduced into event-triggered condition, where event-triggered parameters can be adjusted with the system dynamics evolving. The group consensus protocol is designed based on the neighboring agents information at event-triggered instants, then a new stochastic sampled-data dependent error model is constructed, some group consensus criteria in mean-square can be derived and the feedback matrices can also be obtained. Finally, two numerical examples are provided to illustrate the validity of the theoretical results.

Adaptive event-triggered [formula omitted] fuzzy filter design for nonlinear networked systems via asymmetric LKF approach

This paper studies the problem of the fuzzy H∞ filter design for nonlinear networked control systems through event-triggered communication (ETC) scheme. Firstly, an improved adaptive ETC scheme is proposed to save communication resources. Secondly, an asymmetric Lyapunov-Krasovskii functional (LKF) method is introduced in the H∞ performance analysis of filter error systems. Then, a new sufficient condition is obtained to meet the H∞ performance by combining the method with membership-function-dependent approach. Further, a relaxed co-design method of the corresponding filter and event-triggering parameters is obtained. Finally, two numerical examples are provided to verify the advantage of the new approaches.

Robust Finite-Time Contractive Fault Tolerant Control of Uncertain Nonlinear Network-Based Systems with Adaptive Event-Triggered Communication Scheme

Robust Finite-Time Contractive Fault Tolerant Control of Uncertain Nonlinear Network-Based Systems with Adaptive Event-Triggered Communication Scheme

Novel asynchronous premise reconstruction based adaptive event-triggered control for fuzzy systems with actuator failure

This paper explores the adaptive event-triggered (AET) based variable gains controller design problem for a category of discrete-time nonlinear networked control systems (NCSs) with actuator failure. An AET communication scheme is applied for NCSs to reduce the utilization of limited network bandwidth. For overcoming the asynchronous issue of premise variable caused by AET scheme, a novel asynchronous premise reconstruction technique is introduced. Meanwhile, a new variable gains controller is designed subject to AET approach, where the controller gains will be automatically updated by executing the online iteration algorithm. According to a discontinuous Lyapunov function, sufficient conditions are given to ensure that the closed-loop system is asymptotically stable and satisfies H∞ performance. Finally, in the simulation results, the validity of the proposed control method is verified and it is shown that the proposed scheme can achieve better system performances than the existing design technique with fixed threshold.

Synchronization control of neutral-type neural networks with sampled-data via adaptive event-triggered communication scheme

This paper addresses the problem of synchronization control of neutral-type neural networks with sampled-data, where sampled data will be over a communication network before received by controller. Generally, the communication network is with a bandwidth-limited communication channel. To reduce network burden, an event-triggered scheme is designed between the sampler and communication network. A weak synchronization conditions are derived by using our proposed integral inequality. Finally, a numerical example is given to illustrate the effectiveness and advantage of the proposed results.

Adaptive Event-Triggered SMC for Stochastic Switching Systems With Semi-Markov Process and Application to Boost Converter Circuit Model

In this article, the sliding mode control (SMC) design is studied for a class of stochastic switching systems subject to semi-Markov process via an adaptive event-triggered mechanism. Network-induced communication constraints, semi-Markov switching parameters, and uncertain parameters are considered in a unified framework for the SMC design. Due to the constraint of measuring transducers, the system states always appear with unmeasurable characteristic. Compared with the traditional event-triggered mechanism, the adaptive event-triggered mechanism can effectively reduce the number of triggering than the static event-triggered mechanism. During the data transmission of network communication systems, network-induced delays are characterized from the event trigger to the zero-order holder. The aim of this work is to design an appropriate SMC law based on an adaptive event-triggered communication scheme such that the resulting closed-loop system could realize stochastic stability and reduce communication burden. By introducing the stochastic semi-Markov Lyapunov functional, sojourn-time-dependent sufficient conditions are established for stochastic stability. Then, a suitable SMC law is designed such that the system state can be driven onto the specified sliding surface in a finite-time region. Finally, the simulation study on boost converter circuit model (BCCM) illustrates the effectiveness of the theoretical findings.

Aperiodic Sampled-Data-Based Control for Interval Type-2 Fuzzy Systems via Refined Adaptive Event-Triggered Communication Scheme

This article is devoted to event-triggered stabilization for a class of interval type-2 (IT2) fuzzy systems with aperiodic sampling. First, the IT2 Takagi-Sugeno fuzzy model and sampled-data controllers are established subject to mismatched membership functions. Second, considering a nonuniform sampling case, a refined adaptive event-triggered communication scheme is proposed in a hierarchy form to dynamically adjust the direction and rate of the event-triggered threshold parameter by state changing trend and relative state error, respectively. Thus, a complete dual-directional regulating mechanism with sensitivity to state variation is reasonably created to give extra flexibility, which is beneficial for a preferable tradeoff between control performance and network resource. Third, considering the practical behaviors on the sampling interval, a novel integral type of time-dependent Lyapunov function is constructed. Then, the stability criterion and the controller design approach are derived. Finally, the numerical examples are provided to demonstrate the effectiveness and advantages of the proposed methods.

Adaptive Event-Triggered Fuzzy $H_{\infty }$ Filter Design for Nonlinear Networked Systems

This article studies the problem of the fuzzy $H_{\infty }$ filter design for nonlinear networked control systems through event-triggered communication (ETC) scheme. First, a novel adaptive ETC scheme is given to determine whether the sampled measurement output should be released to communication network or not. Consequently, less communication resources are occupied under the desired $H_{\infty }$ performance. Second, augmented fuzzy line-integral Lyapunov function is introduced in the $H_{\infty }$ performance analysis of filter error systems, such that the information of time derivative of membership functions are fully considered to reduce the conservativeness of networked fuzzy filter design. Different from the existing results, the upper bounds of time derivative of membership functions need not to be known prior. Third, the resulting filter error system is modeled as time-delay system under ETC mechanism and asynchronous premise in a unified framework. As a result, applying Lyapunov theory and inequality technique, new sufficient condition is obtained to meet the $H_{\infty }$ performance for the filter error systems. Further, the corresponding filter and event-triggering parameters are codesigned and solved by a set of linear matrix inequalities. Finally, two examples are offered to demonstrate the advantage of the proposed method.

Networked load frequency control of multi-area uncertain power systems via adaptive event-triggered communication scheme

Load frequency control of power systems is a very important approach to keep stability and security. Unfortunately, the traditional load frequency control is not effective because of the introduction of communication networks in multi-area power systems. In order to overcome this difficulty, sampling-based load frequency control for multi-area power systems is studied via an event-triggered detector. Unlike published works, an adaptive law for event-triggered scheme is given. Since multi-area power systems with event-triggered scheme are hybrid systems, there are a lot of challenges for analysing load frequency control problem. Some lemmas and a new Lyapunov function are developed to overcome these challenges. The obtained stability and stabilization criteria can provide a tradeoff to balance the required communication resources and the desired control performance. Numerical examples verify effectiveness of the obtained results.

Adaptive event-triggered control of discrete-time networked systems against randomly occurring infinite distributed delays, random packet losses and sensor saturation

The saturation input control problem of discrete-time networked systems via adaptive event-triggered communication scheme is discussed in this paper. The criteria are derived by utilising a new Lyapunov functional to guarantee that the considered networked system with randomly occurring infinite distributed delays, random packet losses and sensor saturation is exponentially stable in mean square sense. A novel adaptive event-triggered law is proposed, which is dependent on the exponentially stable index α. The effectiveness of our proposed method is illustrated by both theoretical analysis and numerical simulations.

On designing of an adaptive event-triggered communication scheme for nonlinear networked interconnected control systems

This paper is concerned with the design of adaptive event-triggered scheme for networked nonlinear interconnected systems via T-S fuzzy models. The transmission of control signals is based on a novel adaptive event-triggered communication scheme, where the adaptive threshold is dependent on a dynamic error of the system rather than a predetermined constant as the one in the existing results. The amount of the releasing data is regulated with the adaptive threshold that plays a crucial role in decision of whether releasing the sampled data or not. This technique reflects an inherent dynamic balance between the control performance and the utilization of the network resource. A corresponding Lyapunov function is constructed to achieve sufficient conditions of stability and stabilization. Finally, a simulation example is given to show the effectiveness of the proposed theoretic results.

Adaptive event-triggered control of a class of nonlinear networked systems

This paper investigates an adaptive event-triggered communication scheme (AETCS) for a class of networked Takagi–Sugeno (T–S) fuzzy control systems. The threshold of event-triggering condition has great influence on the maximum allowable number of successive packet losses. Different from the conventional method, the threshold, in this study, is dependent on a novel adaptive law which can be achieved on-line rather than a predefined constant, since the threshold with fixed value is hard to suit the variation of the system. The stability and stabilization criteria are derived by using a new Lyapunov function. Finally, an example is provided to demonstrate the design method.

H∞ tracking control of nonlinear networked systems with a novel adaptive event-triggered communication scheme

This study investigates the problem of tracking control of nonlinear fuzzy systems with a limited network communication. A new adaptive event-triggered data transmission scheme is proposed to save the limited network bandwidth. The threshold of event-triggered condition has a great influence on the rate of data releasing. Different from the conventional method by presetting the threshold as a fixed value, the threshold, in this study, is regulated by the error state of nonlinear systems and the reference model adaptively, which denotes that the rate of data releasing is followed by the external variation. By constructing a proper Lyapunov function with consideration of the proposed adaptive event-triggering condition, an off-line co-design method to achieve the fuzzy controller gains and the parameters of event-triggering condition is developed. An example of Duffing forced-oscillation system with the limited network communication tracking the states of linear reference model is applied to demonstrate the effectiveness of the proposed method.

Network-based H∞ control for T–S fuzzy systems with an adaptive event-triggered communication scheme

This paper extends the prior work of discrete event-triggered communication for networked T–S fuzzy systems, where the next communication instant is determined by an event-triggered communication scheme with a constant threshold and the premises of T–S fuzzy systems and parallel distribution compensation (PDC) fuzzy control rules are synchronous. Firstly, an adaptive event-triggered communication scheme for NCSs is presented, which relaxes the assumption of the prior work that the threshold of event-triggered communication scheme is a preselected constant. Secondly, an asynchronous premise re-construct method for networked T–S fuzzy systems is proposed, which relaxes the assumption of the prior work that the premises of the plant and the PDC control rules are synchronous. We show that the number of transmitted packets generated by the proposed scheme is smaller than those generated by some existing ones while ensuring the desired control performance. Simulations show the effectiveness of the proposed method.

Adaptive event-triggered communication scheme for networked control systems with randomly occurring nonlinearities and uncertainties

This paper proposes a novel adaptive event-triggered communication scheme for networked control systems (NCSs) with randomly occurring nonlinearities and uncertainties. Firstly, an adaptive event-triggered communication scheme for NCSs is proposed, which can adaptively adjust the trigger parameter with respect to the dynamic error to save the limited network resources while ensuring the desired control performance. Secondly, an integrated model of the studied system is built under consideration of the network-induced delay, adaptive event-triggered communication scheme and randomly occurring nonlinearities and uncertainties in a unified framework. Then, sufficient stability criterion to judge the mean-square sense asymptotically stable and stabilization criterion to co-design the parameters of the communication scheme and controller are obtained for the system under consideration. Finally, two examples are given to illustrate the effectiveness of the developed method.