910 publications from this institution
In this chapter, an adaptive event-triggered communication scheme is used to save the limited network bandwidth, while preserving the desired $${H} _{\infty }$$ filter performance.
This article is concerned with the resilient tracking control of a networked control system under cyber attacks. The attacker is an active adversary whose aim is to severely degrade the tracking performance of the system by launching deception attacks on the sensor-to-controller communication channels and denial-of-service attacks on the controller-to-plant channels, respectively. First, a concept of resilient set-membership tracking control is presented, through which the system's true state is guaranteed to reside in a bounding ellipsoidal set of the reference state regardless of the existence of attacks and unknown-but-bounded (UBB) noises. Second, in the case that full information of the system's state is not implicitly trusted in the presence of attacks, a resilient set-membership estimation strategy is provided to secure the state estimates against the deception attacks. Furthermore, based on a recursive computation of a reference state ellipsoid and confidence state estimation ellipsoids, a convex optimization algorithm in terms of recursive linear matrix inequalities is proposed to obtain the gain parameters for both the desired resilient state estimator and the tracking controller. Finally, the effectiveness of the proposed method is illustrated through an Internet-based three-tank system.
This paper considers the stability problem of linear delay-differential systems of neutral type. A discretized Lyapunov functional approach is developed. The resulting stability criteria are formulated in the form of a linear matrix inequality. For nominal systems, the analytical results can be approached with fine discretization. For uncertain systems, the new approach is much less conservative. Numerical examples show significant improvement over approaches in the literature.
This paper deals with the event-triggered distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> filtering for a class of networked systems with sensor networks. The topology of the sensor network is supposed to be time-varying. Whether or not a sampled data packet of a sensor node should be transmitted to its neighbors is determined by a predefined event-triggering condition, which closely depends on the variation of the sensor network topology. By modelling the filtering error system as a switched linear system with time-varying delays, a bounded real lemma (BRL) is derived using Lyapunov-Krasovskii functional approach. Based on the BRL, a sufficient condition on the existence of desired H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> filters is obtained in terms of linear matrix inequalities. An algorithm to the design of both filter parameters and event-triggering parameters is given. It is shown through a numerical example that the proposed method can not only save significantly precious communication resources, and maintain some certain system performance as well.
This paper is concerned with the distributed H∞ state estimation for a discrete-time target linear system over a filtering network with time-varying and switching topology and partial information exchange. Both filtering network topology switching and partial information exchange between filters are simultaneously considered in the filter design. The topology under consideration evolves not only over time but also by an event switch which is assumed to be subject to a nonhomogeneous Markov chain. The probability transition matrix of the nonhomogeneous Markov chain is time-varying. In the filter information exchange, partial state estimation information and channel noise are simultaneously considered. In order to design such a switching filtering network with partial information exchange, stochastic Markov stability theory is developed. The switching topology-dependent filters are derived to guarantee an optimal H∞ disturbance rejection attenuation level for the estimation disagreement of the filtering network. It is shown that the addressed H∞ state estimation problem is turned into a switching topology-dependent optimal problem. The distributed filtering problem with complete information exchanges from its neighbors is also investigated. An illustrative example is given to show the applicability of the obtained results.
This paper investigates sampled-data robust H ∞ control for T–S fuzzy systems with time delay and uncertainties. By introducing the free weighting matrices to deal with the integral items and converting the coupling time-varying matrix inequalities into a group of decoupling matrix inequalities, an innovative delay-dependent stabilization criterion is first presented. Then, a sampled-data H ∞ controller is designed to stabilize the T–S fuzzy system to achieve the prescribed disturbance attenuation level, which is dependent on both the size of state delay and upper bound of allowable sampling period. Since (1) the sawtooth structure of delay is fully considered; (2) neither model transformation nor bounding techniques are employed in deriving the delay-dependent results; and (3) none of the integral items are arbitrarily ignored and magnified, the less conservative results can be expected. A practical application example is given to demonstrate the effectiveness of the proposed methods.
This paper investigates synchronization between two delayed chaotic systems with parameter mismatches. Based on Lyapunov functional approach and generalized Halanay inequality, some delay-dependent criteria are derived to guarantee the synchronization error converges to a bounded ball, whose radius, referred to as the error level, is also estimated. Moreover, an optimization algorithm is established for error level estimate, and the feedback matrix design is also addressed. Finally, a chaotic neural network is used to illustrate the effectiveness of the proposed method.
This paper is concerned with master–slave synchronization for two identical non-autonomous horizontal platform systems by using time-delay feedback control. Compared with some existing results on synchronization for horizontal platform systems, the effect of the time delay in the feedback control on master–slave synchronization is investigated. Applying a delay decomposition approach, some delay-dependent synchronization criteria are established and formulated in the form of linear matrix inequalities (LMIs). Sufficient conditions about the existence of a time delay feedback controller are derived by employing these newly obtained synchronization criteria. The controller gains can be achieved by solving a set of LMIs. One simulation example is given to illustrate the effectiveness of synchronization criteria and the design method.
The Bessel-Legendre inequality plays an important role in stability analysis of linear systems with time-varying delays. However, various integral vectors inherited from the Bessel-Legendre inequality bring some challenging issues, such as the construction of suitable augmented Lyapunov-Krasovskii functionals (LKFs); high-degree polynomial estimation on the derivative of the chosen LKF. This paper offers an overview of recent developments on these issues. First, an instructive review on the construction of suitable augmented LKFs catering for the use of the Bessel-Legendre inequality is given in detail. Second, an in-depth analysis and insightful understanding of high-degree polynomial inequalities on closed intervals are made. Third, recent results on reciprocally convex combination inequalities are briefly discussed. Finally, several challenging problems are presented for future research.
Summary This paper is concerned with overlapping group mode‐dependent H ∞ control for a discrete‐time Markovian jump linear system, where global modes of the system are not completely available for controller design. Firstly, a randomly overlapping decomposition method is developed to reformulate the system by a set of locally overlapping switched groups with accessible group modes. The reformulated system switches among different group modes in an overlapping manner. Secondly, an overlapping group mode‐dependent state feedback controller is delicately constructed. Compared with some existing mode‐dependent controllers in the literature, the proposed controller has three features: (i) it does not require all exact knowledge of global modes; (ii) it takes full advantage of group mode information of the reformulated system; and (iii) it allows overlapping local modes to exist in the formed groups. Thirdly, sufficient conditions on the existence of a desired overlapping group mode‐dependent state feedback controller are derived such that the resultant closed‐loop system is stochastically stable with prescribed H ∞ performance. Furthermore, the proposed method is extended to design overlapping group mode‐dependent state feedback controllers subject to incomplete mode transition probabilities. The proposed overlapping group mode‐dependent framework is shown to be more general and includes traditional Markovian jump linear systems with completely accessible global modes as its special case. In the case of only one group in the reformulated system, it is shown that some existing result in existing literature can be retrieved. Finally, two illustrative examples are given to show the effectiveness of the obtained theoretical results. Copyright © 2014 John Wiley & Sons, Ltd.
This paper deals with the problem of fault detection filter (FDF) design for a class of networked control systems under considering both the network-induced time delay and data dropout. A novel form of an observer-based hybrid FDF is introduced to be the residual generator. Under the assumption of network-induced time delay being time-varying and bounded, the FDF design problem can be transformed as an H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</inf> -optimization problem for linear systems with interval time-varying delay. A delay-dependent sufficient condition is derived by using Layapunov-Krasovskii approach and an associated solution of the problem can be obtained by solving a set of linear matrix inequalities (LMIs). A simulation example is given to demonstrate the effectiveness of the proposed method.
The high integration of physical processes and cyber infrastructure greatly promotes the speedy growth of cyber-physical systems (CPSs), which has been turning into a critical essence of the so-cal...
A novel model-free predictive mixed-sensitivity H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control scheme is proposed and applied to grid-connected solar power generation systems. The predictive sensitivity and the predictive complementary sensitivity are defined based on the predictive model. The model-free predictive mixed-sensitivity H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> controller is derived from input/output measurements to achieve an optimal predictive mixed-sensitivity performance using a maxmin optimization method. Then, a simulation system for solar power generation systems is established using SimPowerSystems. Finally, the simulations are conduced to show the effectiveness of the proposed model-free controller, which outperforms the conventional proportional-integral and model-free linear quadratic Gaussian controllers in the tracking performance and the robustness of solar power generation systems.
This paper deals with the resilient distributed control of a platoon of automated vehicles under DoS attacks. First, an event-triggered transmission mechanism resilient to energy-limited DoS attacks is proposed to save the possible bandwidth of vehicle-to-vehicle communication channels. A consensus-based distributed control strategy, which is implemented on each vehicle, is developed to account for the information interaction of leading and following vehicles under the proposed resilient event-triggered data transmission mechanism. Second, an attack-tolerant performance index with certain resilience level is put forward in such a way to achieve resilience evaluation of the vehicular platoon system. Third, sufficient conditions are derived for ensuring the consensus of the resulting vehicular platoon system while preserving the prescribed resilience performance requirement. Furthermore, a co-design criterion for determining the distributed platoon controller and triggering condition is presented. Finally, simulation under a predecessor-leader following topology is presented for validation of the obtained results.
