910 publications from this institution
This Letter investigates synchronization of two nonidentical Lur'e systems with time-varying delay and parameter mismatches via impulsive control. Based on the theory of impulsive functional differential equations, sufficient conditions for impulsive synchronization with a bound on the synchronization error are derived. An illustrative example is provided to validate the proposed method.
This paper introduces a new discrete-time filter proportional–integral–derivative (FPID) controller framework for linear time-invariant (LTI) systems. The discrete-time FPID controller plays an important role in both determining the dynamic response of the system and further improving the performance of the controller in itself. However, the introduction of the filter parameter brings more challenge for the design of discrete-time FPID controllers than that of discrete-time PID controllers. A novel result on the co-design of such a controller via dominant eigenvalue assignment is first provided, which enables us to tune the controller directly in accordance with the desired system performance indexes. Then, a further result on the discrete-time FPID controller design to improve the dynamic response of the closed-loop system is derived by placing the non-dominant eigenvalues in some assigned region. Compared with the discrete-time PID controller, on the one hand, the discrete-time FPID controller plays a significant role in improving the output of the controller in addition to guaranteeing the desired dynamic performance of the closed-loop system. On the other hand, a discrete-time FPID controller makes it possible to expand the effective parameter region and give a set of parameters which makes the controller achieve the objective of dominant eigenvalue assignment for the closed-loop system when a traditional discrete-time PID controller cannot do. Numerical examples have illustrated the effectiveness of the proposed results.
This paper investigates stability and passivity of negative feedback interconnection of two passive systems, which are interconnected through communication networks. The insertion of communication networks between negative feedback interconnected passive systems inevitably induces delays and data packet dropouts. To model the network-based negative feedback interconnected system, an appropriate network scheduling method is presented to deal with time-varying network-induced delays and data packet dropouts. By constructing a novel discontinuous Lyapunov-Krasovskii functional, a less conservative sufficient condition for the network-based feedback interconnected system to be asymptotically stable is derived. Based on the stability condition, a new sufficient condition to make the negative feedback interconnected system in network environments remain passive is developed. A numerical example is provided to demonstrate the effectiveness of the design method.
The robust H/sub /spl infin// filtering problem for a class of continuous-time uncertain linear descriptor systems with time-varying discrete and distributed delays is investigated. The time delays are assumed to be constant and known. The uncertainties under consideration are norm-bounded, and possible time-varying, uncertainties. Sufficient condition for the existence of an H/sub /spl infin// filter is expressed in terms of strict linear matrix inequalities (LMIs). Instead of using decomposition technique, a unified form of LMIs is proposed to show the exponential stability of the augmented systems. The condition for assuring the stability of the "fast" subsystem is implied from the unified form of LMIs, which is shown to be less conservative than the characteristic equation based conditions or matrix norm-based conditions. The suitable filter is derived through a convex optimization problem. A numerical example is given to show the effectiveness of the method.
This article addresses the problem of distributed resilient finite-time control of multiple heterogeneous battery energy storage systems (BESSs) in a microgrid subject to denial-of-service (DoS) attacks. Note that DoS attacks may block information transmission among BESSs by preventing the BESS from sending data, compromising the devices and jamming a communication network. A distributed secure control framework is presented, where an acknowledgment (ACK)-based attack detection strategy and a communication recovery mechanism are introduced to mitigate the impact of DoS attacks by repairing the paralyzed topology graphs caused by DoS attacks back into the initial connected graph. Under this framework, a distributed resilient finite-time secondary control scheme is proposed such that frequency regulation, active power sharing, and energy level balancing of BESSs can be achieved simultaneously in a finite time; meanwhile, operational constraints can be satisfied at any control transient time. Moreover, based on theoretical analysis, the impact of the duration time of DoS attacks on the convergence time of the control algorithm can be explicitly revealed. Finally, validity and effectiveness of the proposed control scheme are demonstrated by case studies on a modified IEEE 57-bus testing system.
This article proposes several criteria for the distribution of roots of quasi-polynomials of neutral type with complex coefficients. Compared with Pontryagin's results, the derived criteria can be numerically implemented because the interval of the frequency for analyzing the behavior of the quasi-polynomial can be determined. Moreover, some Hurwitz stability criteria to judge whether all the roots of the quasi-polynomials are in the open left-half complex plane are provided. These Hurwitz stability criteria can be employed to analyze the stability of linear time-invariant systems with commensurate delays. It should be pointed out that on the one hand, the derived criteria are general since quasi-polynomials of retarded type and quasi-polynomials with real coefficients are their special cases. On the other hand, the conditions in Hurwitz stability criteria are all necessary and sufficient. Furthermore, as a special case, several criteria for the distribution of roots of the quasi-polynomials with real coefficients are presented. For the proposed criteria, this article provides some examples to illustrate the implementation and presents the detailed analysis and proofs.
This paper is concerned with non-fragile H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> filtering for linear systems in network environments. The filtering error system is modeled as a linear system with an interval time-varying delay. Then a delay-decomposition approach is employed to derive a sufficient condition such that the filtering error system is asymptotically stable with a prescribed H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> disturbance attenuation level, where the non-fragility of filters, network-induced delays and data packet dropouts are taken into account simultaneously. Based on this condition, a networked non-fragile H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> filter with additive uncertainties can be designed by solving a set of linear matrix inequalities. A numerical example is given to demonstrate the effectiveness of the proposed design method.
This paper is concerned with the delay-dependent robust stability problem for uncertain linear systems with interval time-varying delay. The time-varying delay is assumed to belong to an interval and no restriction on the derivative of the time-varying delay is needed, which allows the delay to be a fast time-varying function. The uncertainty under consideration is norm-bounded, and possibly time-varying, uncertainty. Based on the Lyapunov–Krasovskii functional approach, a stability criterion is derived by introducing some relaxation matrices that can be used to reduce the conservatism of the criteria. Numerical examples are given to demonstrate effectiveness of the proposed method.
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper is concerned with the problem of local and global asymptotic stability for a class of discrete-time recurrent neural networks, which provide discrete-time analogs to their continuous-time counterparts, i.e., continuous-time recurrent neural networks with distributed delay. Some stability criteria, which include some existing results as their special cases, are derived. A discussion about the dynamical consistence of discrete-time neural networks versus their continuous-time counterparts is provided. An <emphasis emphasistype="bold"><emphasis emphasistype="italic">unconventional finite difference method</emphasis></emphasis> is proposed and an example is also given to show the effectiveness of the method. </para>
Band selection, aiming at screening representative spectral bands and eliminating redundant information, has long been a popular topic in hyperspectral imagery (HSI) processing, and has garnered a growing concern owing to the advancements in sparse representation techniques. Traditional sparsity-based methods are frequently impeded by the issue of inadequate or even unattainable training samples. Moreover, these approaches may fall short in thoroughly investigating the spatial structural information and spectral contextual information. To this end, this paper proposes a new unsupervised band selection scheme, namely, pseudo-label guided sparse regression with spatial and spectral regularization (PSR2BS), which embeds band selection into an unsupervised sparse regression model. Specifically, a pseudo-label matrix is jointly learned to serve as a discriminative cluster indicator, during which it guides the projection matrix in selecting informative bands. To leverage the spatial information within HSI, an image is segmented into different distinct homogeneous regions to generate representation samples, wherein the local structural information is also explored through spatial regularization. Furthermore, a spectral regularization term is introducing, making full use of prior information regarding similarity within spectral bands. To solve the proposed model, an effective and efficient iterative optimization algorithm is developed. Our extensive experiments on classification and anomaly detection across six real HSI datasets clearly demonstrate the superior performance of the proposed PSR2BS compared with state-of-the-art competitors.
This paper is concerned with overlapping mode-dependent H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control for a discrete-time Markov jump linear system in the presence of overlapping local operation modes and incomplete mode transition probabilities. By developing a randomly overlapping decomposition method, the system with deficient global operation modes is reformulated by a set of locally overlapping switched groups with accessible group and local modes. An overlapping group- and local-mode-dependent state feedback controller is delicately constructed. Unlike some existing controllers proposed in the literature, we do not require complete global mode information, but take full advantage of the knowledge of group and local modes of the reformulated system. Moreover, overlapping local modes are allowed to be existed in the formed groups. The stability analysis and control design procedures are developed based on the stochastic Lyapunov functional approach. The proposed framework is shown to be more general, which covers the traditional Markovian jump linear system with completely available global modes as a special case. In the case of only one local group, it is also shown that some existing results from the literature can be regarded as a special case of our derived results. A simulation example is finally presented to show the effectiveness and merits of the proposed method.
This paper deals with the problem of odor source localization using multiple mobile robots. A cooperative control solution, which is used to coordinate the robot group to locate the odor source, is proposed and independently executed by each robot. Firstly, a particle filter, which can estimate the position of the odor source by using all observations among the robot group, is used. Secondly, based on the estimated position of the odor source, a movement direction is planned by a leader robot, which currently detects odor clues. Thirdly, two decision-making control laws, which can enable the robot group to make a parallel motion or a circular motion in terms of the planned direction and the estimated position of the odor source, are developed. Finally, the performance capabilities of the proposed cooperative control solution are illustrated for the problem of odor source localization.
An intelligent memory-based event-triggered impulsive control (METIC) scheme is proposed to address the stabilization problem for a class of nonlinear systems while accounting for exponential convergence, dynamic performance, and control frequency. The contribution of the scheme is the incorporation of weighted historical data into the triggering condition, using both fixed thresholds and adaptive thresholds based on Q-learning. By utilizing the system states at the two most recent triggering instants to construct the triggering condition, several exponential stability criteria are first established via an iterative approach. Then, in the general case in which additional historical states are included, a comparison system approach is employed to derive new stability conditions. Furthermore, to adaptively tune the event-triggering thresholds and improve system performance, a Q-learning-based optimization algorithm is developed, and a set of easily verifiable stability conditions is derived within the framework of switched system theory. For both fixed-threshold and adaptive-threshold cases, Zeno behavior is rigorously excluded through theoretical analysis. Finally, comparative simulation results are presented to demonstrate the effectiveness of the proposed method.
This paper is concerned with global asymptotic stability of delayed neural networks. Notice that a Bessel-Legendre inequality plays a key role in deriving less conservative stability criteria for delayed neural networks. However, this inequality is in the form of Legendre polynomials and the integral interval is fixed on . As a result, the application scope of the Bessel-Legendre inequality is limited. This paper aims to develop the Bessel-Legendre inequality method so that less conservative stability criteria are expected. First, by introducing a canonical orthogonal polynomial sequel, a canonical Bessel-Legendre inequality and its affine version are established, which are not explicitly in the form of Legendre polynomials. Moreover, the integral interval is shifted to a general one . Second, by introducing a proper augmented Lyapunov-Krasovskii functional, which is tailored for the canonical Bessel-Legendre inequality, some sufficient conditions on global asymptotic stability are formulated for neural networks with constant delays and neural networks with time-varying delays, respectively. These conditions are proven to have a hierarchical feature: the higher level of hierarchy, the less conservatism of the stability criterion. Finally, three numerical examples are given to illustrate the efficiency of the proposed stability criteria.
This paper focuses on master-slave synchronization for two identical chaotic labyrinth systems with different initial conditions by using time-delay feedback control. By employing the differential mean value theorem to deal with the nonlinear term of the error system, the error system is modeled as a polytopic system. Applying a delay decomposition approach, a delay-dependent synchronization criterion is established and formulated in the form of linear matrix inequalities (LMIs). A sufficient condition about the existence of a time delay feedback controller is derived by employing this newly-obtained synchronization criterion. The controller gain can be achieved by solving a set of LMIs. One simulation example is used to illustrate the effectiveness of the synchronization criterion and the design method.
No abstract is provided for this article.
This paper is concerned with the distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus filtering problem for a networked system with random and time-varying state delays, switching network topology and different communication channels-induced packet dropouts with different missing rates. The purpose of the addressed problem is to design a distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus filter to guarantee the robustness of the filtering error system to both random and time-varying state delays, different communication channels-induced packet losses and switching network topology, and the minimization of the consensus-based estimation deviations in the H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> sense. On the basis of the T-S fuzzy approach and the Lyapunov functional, distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus filter design criteria are derived such that the filtering error system is mean-square stochastically stable, and an optimal H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> disturbance rejection attenuation performance index is achieved for the consensus-based estimation deviations. A simulation example is conducted to verify the usefulness of the proposed filter design approach.
