Asynchronous Switching Research Articles

Sampled-point-based partition control of linear switched systems with a novel asynchronous switching rule

This paper investigates the aperiodic sampling stabilisation problem for a class of switched linear systems under asynchronous switching. Based on a novel dynamic sampling rule, a sampling-point-based partition-dependent discontinuous Lyapunov functions control approach are developed to make the considered closed-loop switched systems be globally asymptotically stable. Compared with the existing results, the proposed control method permits frequent switching in a sampling interval for subsystems. But the frequent information transmission to the matched controllers and the negative effect of long asynchronous running on system performance can be nicely handled in this paper. Moreover, the partitioned Lyapunov functions are allowed to increase in some segments of the synchronous operating intervals. Tighter synchronous duration and switching number which are determined by more than affine functions make the switching signal more flexible. Finally, simulation analyses of two examples show the advantages of the developed control strategy.

A quintuple plasmon-induced transparency multifunction switch based on the polarization-sensitive graphene-based metamaterial

A monolayer metamaterial consisting of a rectangle graphene strip and four L-shaped graphene blocks was proposed to achieve a quintuple plasmon-induced transparency (quintuple-PIT). The numerical simulation results based on the finite difference time domain method agree well with the calculated results of the coupled mode theory. By modulating the Fermi energy level of graphene, an octuple-frequency asynchronous switch and a sextuple-frequency synchronous switch are designed and studied, which have excellent amplitude modulation degree (up to 97.7%), extinction ratio (up to 16.41 dB), insertion loss (low to 5.4%), and dephasing time(low to 3.86 ps). Furthermore, the results show that the proposed metamaterials has polarization-sensitive characteristics due to their non-central symmetry. Further research shows that the group index is as high as 604 which has a good slow light effect and can be used for optical storage. Hence, the quintuple-PIT proposed structure in this paper has good application value in the expansion of multi-function optical switches and the research of high-quality optical memory.

Time‐regularization event‐triggeredH∞control for switched linear systems with frequent asynchronism

AbstractThis paper addresses the time‐regularization event‐triggered control problem for a class of continuous‐time switched systems with frequent asynchronism and external disturbances. In the system, both the system state and the switching information are transmitted to the controller only at the event‐triggered sampling instants, which may cause the occurrence of asynchronous switching behavior. To solve the problem, we first propose a time‐regularization event‐triggered mechanism, which not only avoids Zeno behavior efficaciously, but also allows the system to switch multiple times in the holding interval. Then, based on the time‐regularization event‐triggered mechanism, the error system is modeled as a sampled switched delay system with augmented switching signal. After that, sufficient conditions for the exponentially stability and weighted performance of the switched system under average dwell time are derived by constructing multiple switching Lyapunov functions. Finally, a circuit example is given to illustrate the effectiveness of the proposed method.

A Stackelberg Game Approach to the Stability of Networked Switched Systems Under DoS Attacks

This paper investigates the stability of networked switched systems under DoS attacks by a Stackelberg game approach. Firstly, the non-cooperative competition between the attacker and the controller is characterized as a switched Stackelberg game. The delivery rate of data packets and controller gains compose the strategy sets of the attacker and the controller, respectively. Then, the switched optimal Stackelberg strategy is obtained from the corresponding Stackelberg equilibrium. Considering the open-loop and asynchronous switching cases caused by DoS attacks, sufficient conditions for the exponential mean-square stability of the system are obtained. Finally, switched RLC circuit systems are provided to verify the effectiveness of the proposed methods.

Observer-based event-triggered control for continuous-time switched linear parameter-varying systems

This paper researches the interval observer–based event-triggered control of switched linear parameter-varying (LPV) systems, which involve unknown external disturbance and measurement noise. First, we offer an event-triggering condition and a controller which are correlated with state estimations. Then, by analyzing the relationship between switching sequences and sampling sequences, we model the resulting systems as switched time-delay systems. It deserves to note that the mismatches of the switching signal for the controllers and the systems may occur due to the sampling of switching signal. Using the merging switching signal technique and the multiple Lyapunov–Krasovskii functional method, and thinking over both synchronous and asynchronous switching of the systems and the controllers, we acquire relevant conditions which are used to realize the stability of the whole switched LPV closed-loop systems under the mode-dependent average dwell time (MDADT) switching. Next, we give a specific algorithm to design the controller gains. Finally, a numerical example is provided to verify the superiority of the outcomes.

Finite/Prescribed-Time Cluster Synchronization of Complex Dynamical Networks With Multiproportional Delays and Asynchronous Switching

This article focuses on the finite-time and prescribed-time cluster synchronization problems of switched complex networks with proportional delays. Considering that the matched controller often switches behind the switched systems, asynchronous switching law and switching parameters have been introduced to the complex dynamical networks. By applying the stability theory of dynamical systems and the average dwell time approach, some sufficient criteria in form of linear matrix inequalities have been developed to guarantee such networks finite/prescribed-time cluster synchronization under the pinning control scheme. Finally, one numerical example is presented to show the effectiveness of the theoretical results.

Finite‐time stochastic dissipative output tracking control of semi‐Markov jump systems via an adaptive event‐triggered mechanism

AbstractThis work focuses on the output tracking control for a class of continuous‐time semi‐Markov jump systems (SMJSs). In the controller design, not only the finite‐time stochastic boundedness (FTSB), but also the dissipative performance over a finite‐time interval is considered. In order to save communication resources, a version of adaptive event‐triggered mechanism (AETM) is utilized. Different from the traditional static event‐triggered mechanism, the threshold coefficient in AETM is time‐varying and can be adjusted in real‐time to fit the system evolution. Moreover, the asynchronous switching between the controller modes and the plant modes is taken into account. The design objective is to synthesis an adaptive event‐triggered asynchronous state‐feedback controller such that not only the augmented closed‐loop system is FTSB with a certain level of dissipative performance, but also the communication burden can be reduced to some extent. It is the first attempt to investigate the output tracking control of SMJSs over a finite‐time interval. By constructing a plant model‐dependent Lyapunov function, a set of conditions is derived for the FTSB analysis, based on which a controller design algorithm is presented. Finally, an illustrative example is given to verify the availability of the theoretical findings.

Output tracking and disturbance rejection control for switched systems under asynchronous switching

In this article, we discuss the output tracking and disturbance rejection problem for a class of switched systems with state time-varying delay under asynchronous switching. More precisely, proportional–integral control law is implemented to obtain the required tracking performance for the addressed systems. In addition, an improved equivalent-input-disturbance estimator is utilized to estimate and suppress the external disturbances. Further, the asynchronous switching phenomenon is considered between the proposed controller and the system mode. Setting a proper choice of multiple piecewise Lyapunov–Krasovskii functional, a group of required condition is established in the structure of linear matrix inequalities by using an average dwell time approach. At last, two numerical examples and their simulations including the DC motor driving model are displayed to justify the efficiency and applicability of the proposed control synthesis.

Dwell-time-dependent asynchronous dissipative control for discrete-time switched positive systems with linear supply rates

This article investigates the issues of dissipativity analysis and synthesis of discrete-time switched positive systems, in the presence of asynchronous switching. A switching retard, between activation of positive subsystems and activation of candidate controllers, is taken into account. The dwell-time dependent linear copositive storage functions and linear supply rates are adopted to capture the property of dissipativity, where the state of each subsystem is required to stay in positive orthant. Sufficient conditions are also attained such that the closed-loop system with time-varying asynchronous state-feedback controllers maintains positivity and meets strict (q,r)-α-dissipative performance. Furthermore, all derived criteria are presented in the form of linear vector inequalities. Finally, two examples including the compartmental model are offered to illustrate the validity of derived results.

Quantized event‐triggered adaptive control for switched nonlinear systems with vanishing control gains

SummaryThis article studies the quantized event‐triggered adaptive tracking control problem for a type of switched nonlinear systems with parameter uncertainties, where the corresponding control problem for each subsystem can be unsolvable owing to vanishing control gains at some points. A constructive design scheme is established by triple design of quantized event‐triggered adaptive controller of each subsystem and a switching dynamic event‐triggering mechanism dependent on quantization and a hysteresis‐type state‐dependent switching law. The developed scheme handles not only the asynchronous switching between candidate event‐triggered adaptive controllers and subsystems, but also the asynchronous switching between candidate quantizers and subsystems. Both the switching law and the event‐triggering mechanism do not cause Zeno behavior. As a special case, a sufficient condition to address the quantized event‐triggered adaptive control problem for the switched nonlinear systems is also derived under dwell‐time switching. Finally, the effectiveness of the developed schemes are verified by a numerical example and a networked one‐link manipulator with motor dynamics.

Robust H∞ control for switched stochastic nonlinear systems under sampled‐data

AbstractIn this article, we consider an output feedback control problem of switched stochastic nonlinear systems under sampled‐data, where the switching converts to asynchronous switching if the switching occurs within the sampling interval. We first construct the output feedback sampled‐data controller by the back‐stepping method. And the limiting conditions of the sampling period are obtained based on the average dwell time method. We show that the closed‐loop system is globally mean‐square asymptotically stable and has a weighted ‐gain. Moreover, our theoretical results are applied to two numerical examples to demonstrate the validity of the proposed method.

Stability analysis of hybrid stochastic delay differential equations with asynchronous switching and discrete observations

AbstractThis paper studies the hybrid stochastic delay differential equations (SDDEs) with asynchronous switching and discrete observations. For SDDEs based on discrete observations, there are two methods: The discrete‐time approach and the input time delay method. For linear solvable equations, the discrete‐time approach is feasible but for unsolvable nonlinear hybrid SDSs, the results of the discrete‐time approach have not been discussed. So, it is natural to ask: Is the discrete‐time approach still workable for nonlinear hybrid SDSs? This paper focuses on this problem. By using tools of stochastic analysis, constructing Lyapunov functional and using the discrete‐time approach, the stability of hybrid SDSs by discrete‐time feedback control is obtained. Finally, a numerical example is presented to verify the theoretical result.

Stabilization of Switched Logical Networks: Asynchronous Switching Control

This brief deliberates on the stabilization of switched logical networks (SLNs) under the asynchronous switching controller. The studied system takes into account the asynchronous switching phenomenon that the operating subsystem does not match the controller mode caused by non-ideal conditions. Our purpose is to find suitable conditions under which the SLN achieves stabilization under the asynchronous switching controller. By combining the Lyapunov method of logical networks and the mode-dependent average dwell time method, a sufficient criterion is first put forward for the stabilization of SLNs under the asynchronous switching controller. Furthermore, the obtained results are extended to the stabilization of SLNs with logical switching. An example of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$lac$ </tex-math></inline-formula> operon in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E.~coli$ </tex-math></inline-formula> is finally given to validate the addressed results.

Directed-Graph-Learning-Based Diagnosis of Multiple Faults for High Speed Train With Switched Dynamics.

This article addresses the distributed multiple fault isolation, modeling, and the closed-loop fault estimation under asynchronous switching for high speed train (HST) with switched dynamics, which is composed of traction, coasting, and braking. First, directed-graph-quantum-learning-based multiple-agent system (MAS) classifiers are introduced to characterize the joints effects of multiple faults. Some sufficient conditions are derived under the condition that the multiple fault topology contains a directed spanning tree and cycle edge, and these conditions guarantee that the multiple fault isolation problem can be solved under randomized learning techniques. Then, single-integrator agents are employed to capture the time-varying topology of multiple fault modeling, in which edge agreement and persistence condition are used to guarantee asymptotic consensus. After that, a novel robust fault estimation design along with the switched Lyapunov function and average dwell time is proposed for the possible power actuator faults subject to asynchronous switching and electromagnetic interferences. In addition, switched estimators are designed such that the closed-loop system is asymptotically stable. A multiple fault isolation and estimation case is investigated to validate the application of this methodology.

Multimode diagnosis for switched affine systems with noisy measurement

We study a diagnosis scheme to reliably detect the active mode of discrete-time, switched affine systems in the presence of measurement noise and asynchronous switching. The proposed scheme consists of two parts: (i) the construction of a bank of filters, and (ii) the introduction of a residual/threshold-based diagnosis rule. We develop an exact finite optimization-based framework to numerically solve an optimal bank of filters in which the contribution of measurement noise to the residual is minimized. The design problem is safely approximated through linear matrix inequalities and thus becomes tractable. We further propose a thresholding policy along with probabilistic false-alarm guarantees to estimate the active system mode in real-time. In comparison with the existing results, the guarantees improve from a polynomial dependency in the probability of false alarm to a logarithmic form. This improvement is achieved under the additional assumption of sub-Gaussianity, which is expected in many applications. The performance of the proposed approach is validated through a numerical example and an application of the building radiant system.

Dynamic Event-Triggered Adaptive NN Control for Switched Uncertain Nonlinear Systems.

This article is concerned with the problem of dynamic event-triggered adaptive neural network (NN) control for a class of switched strict-feedback uncertainty nonlinear systems. A novel switched command filter-based dynamic event-triggered adaptive NN control approach is set up by exploiting the backstepping and command filter and the common Lyapunov function method. Since adaptive controllers of subsystems are event triggered, then if the switching happens between any two consecutive triggering instants, asynchronous switching will arise between candidate controllers of subsystems and subsystems. Unlike the existing literature, where maximum asynchronous time is restricted, without any strict limitations on maximum asynchronous time being needed in this article, the asynchronous switching problem is directly handled by proposing a novel switching dynamic event-triggered mechanism (DETM) and event-triggered adaptive controllers of subsystems. Moreover, a piecewise constant variable is introduced into the switching DETM, which overcomes the difficulty of switched measurement error being discontinuous. Also, a strictly positive lower bound of interevent times is obtained. Finally, a continuous stirred tank reactor system and a numerical example are presented to demonstrate the effectiveness of the developed approach.

Period-Sampled Switching Event-Triggered Control of Switched Linear Systems

This brief focuses on the event-triggered control (ETC) problem for a class of switched linear systems in which the controller updates the sampled information of both the system states and the switching signal only at the moment of event triggering. When the system switching occurs in the holding interval, the controller does not update the switching signal, which leads to the asynchronous switching behavior between the controller and the switched system. To solve the problem, we develop a new switching event-triggered mechanism (ETM) with periodic sampling by introducing a relative threshold function and an asynchronous related jump function with a tuning parameter. This period-sampled switching ETM can save computing resources and avoid Zeno behavior. Then, based on the multiple Lyapunov functional technique and the average dwell time (ADT) method, some sufficient conditions for global uniform exponential stability (GUES) of the closed-loop system are proposed. Besides, the corresponding solvability conditions for the co-design of the switching signal and the event-triggered controller are established. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed method.

Input-to-State Stability of Switched Nonlinear Time-Delay Systems With Asynchronous Switching: Event-Triggered Switching Control

This letter addresses the input-to-state stability (ISS) and integral ISS (iISS) problems for switched nonlinear time-delay systems (SNTDSs) with asynchronous switching by the event-triggered switching control (ETSC) technique, where the switching times are generated by a novel Lyapunov-based event-triggered mechanism (ETM). Based on the relationship between the new ETM and the jump strength of adjacent Lyapunov functions, sufficient conditions of ISS and iISS for SNTDSs with asynchronous switching are presented, which can exclude the Zeno behavior. Since switches only occur when the event is triggered, the burden of information transmission for SNTDSs can plummet. Finally, two practical examples are introduced to verify the effectiveness of our proposed methods.

Stability of Lurie-type systems with asynchronous and synchronous switching and constant delays

The problems of analysis for systems with synchronous and asynchronous switching have been actively studied for the linear case. In this paper, a switched system of difference-differential equations, in which the right-hand side consists of a linear term and an essentially nonlinear part containing sector-type components is considered. This kind of systems belongs to the class of Lurie indirect control systems. Sufficient conditions on the system parameters and the switching law are investigated for asymptotic stability to be guaranteed both in the case of synchronous switching between subsystems and in asynchronous one. In the latter case it is supposed that the nonlinear delayed part switches with a lag equal to the corresponding delay. It is required that stability should be preserved for any constant positive delays. The problem is solved using the Lyapunov — Krasovsky approach. The functional is chosen that includes a quadratic form and integrals of nonlinearities. Restrictions that ensure asymptotic stability for an arbitrary switching law are found. With such an approach for the asynchronous case these conditions turn out to be less restrictive. By using multiple functionals the restrictions on the lengths of intervals between switchings are also obtained. This type of conditions are similar for both cases of synchronous and asynchronous switching. Theoretical results are demonstrated by a specially selected example.

The Couple‐Group Consensus of Heterogeneous Multiagent Systems with Asynchronous Switching in Cooperative‐Competitive Networks

This paper investigates the problem of leader‐following or leaderless couple‐group consensus of heterogeneous multiagent systems (HMASs) with cooperative‐competitive interaction, asynchronous switching, and controller faults. Some novel protocols have been proposed to solve the couple‐group consensus of the two kinds of HMASs. Compared with the existing results, asynchronous control, controller faults, leaders, and the competitive‐cooperative interaction are all considered in these novel protocols. By using linear matrix inequality, graph theory, Lyapunov functional theory, and model‐dependent dwell time technique (MDADT), some sufficient conditions have been gained for the leader‐following or leaderless couple‐group consensus of these systems. The obtained results show that the couple‐group consensus of HMASs can be transformed into determining the stability of the related switching linear system. These results can also be applied to HMASs with weakly connected topology without satisfying the demand of in‐degree balance, strong connectivity, or containing a spanning tree. Some simulation experiments are given to prove the validity of the obtained results.