Publications

This paper is dealing with the problem of adaptive event‐triggered leader‐follower consensus for multi‐agents systems with output constraints and dead‐zone inputs. By introducing an advanced nonlinear mapping technique to obtain the unconstrained auxiliary variables of constrained system states, a new systems model without output constraints is constructed. Unlike existing schemes, the proposed strategy can be used in both constrained and unconstrained situations without requiring changes to the control structure. Moreover, a state estimator is constructed to observe the unavailable states. To conserve communication resources, an event‐triggered rule with a dynamic threshold is designed to decrease superfluous information transmissions from the controller to the actuator. It is proven that all signals in closed‐loop systems are ultimately bounded, and the system output does not violate the given constraint range. At last, a numerical simulation example is provided to confirm the correctness and efficiency of the proposed method.

This paper investigates a robust guaranteed cost tracking control problem for thrust-limited spacecraft rendezvous in near-circular orbits. Relative motion model is established based on the two-body problem with noncircularity of the target orbit described as a parameter uncertainty. A guaranteed cost tracking controller with input saturation is designed via a linear matrix inequality (LMI) method, and sufficient conditions for the existence of the robust tracking controller are derived, which is more concise and less conservative compared with the previous works. Numerical examples are provided for both time-invariant and time-variant reference signals to illustrate the effectiveness of the proposed control scheme when applied to the terminal rendezvous and other astronautic missions with scheduled states signal.

This paper is concerned with a non-fragile H ∞ state feedback control issue for linear parameter-varying collaborative adaptive cruise control systems subject to denial-of-service attacks. The dynamics of the collaborative adaptive cruise control system is described by a linear model where the deviation of the position and the velocity are selected as the state variables. The attack model is utilized, thereby better reflecting the randomly occurring phenomenon of the denial-of-service attacks based on a sequence of binary random variables. The main objective of this note is to develop a non-fragile state feedback control scheme such that, for denial-of-service attacks and possible parameter variations in controller gains, the exponential mean-square stability and the predefined performance index for the system states are guaranteed simultaneously. By using the matrix analysis techniques and Lyapunov stability theory, sufficient conditions for the desired controller are established and solved based on the solutions to the linear matrix inequality conditions. Finally, a three-car model is provided to check the feasibility of the designed control scheme.

This paper examines the problem of observer-based sliding mode control designs for a class of descriptor Takagi-Sugeno fuzzy systems with time delay and uncertainties. Specifically, based on the detailed discussions on the existence conditions, a reduced-order robust observer is designed first where the influences of the uncertainties are totally removed. Second, by choosing appropriate coordinate transformations and matrix decompositions, an actual and a virtual sliding mode variables are constructed, and an observer-based sliding mode controller is developed to handle the uncertainties such that the virtual sliding mode surface can be reached and maintained in a finite time, whereas the actual sliding mode variable approaches to zeros asymptotically. And then, we prove that the system asymptotic stability can be guaranteed after the virtual sliding mode surface has been reached or the actual sliding mode variable approached to zero. In addition, the existence conditions for both the observer and the sliding mode controller are given in strict linear matrix inequality forms. Finally, a simulation example is given to demonstrate the effectiveness of the proposed method.

This paper is concerned with the problem of H ∞ filtering for a class of two-dimensional Markovian jump linear systems described by the Fornasini–Marchesini local state-space model. The systems under consideration are subject to state-delays and deficient mode information in the Markov chain. The description of deficient mode information is comprehensive that simultaneously includes the exactly known, partially unknown and uncertain transition probabilities. By invoking the properties of the transition probability matrix, together with the convexification of uncertain domains, a new H ∞ performance analysis criterion for the filtering error system is firstly derived. Then, via some matrix inequality linearisation procedures, two approaches for the filter synthesis are proposed. It is shown that both the full-order and reduced-order filters can be constructed by solving a set of linear matrix inequalities. Finally, simulation studies are provided to illustrate the effectiveness of the proposed design methods.

This paper investigates the problem of static output feedback control for a class of nonhomogeneous Markovian jump system (NMJS) with asynchronous time delays (ATDs). Since the ATDs subject to uncertain transition probabilities (TPs) are taking into account in a practical phenomenon, new approaches are introduced to deal with the ATDs characterized by nonhomogeneous Markov processes. It is assumed that the communication links are not perfect due to its detrimental effect on the performance of systems. Stochastic variables are presented to characterize the data transmission, which are depending on operation modes and satisfying the Bernoulli distribution. Sets of slack variables are adopted to decouple the product terms between system matrices and Lyapunov matrices. Based on an extended Lyapunov function combined with Finsler inequality approach, the robust static output-feedback controller is designed for the closed-loop NMJS. Finally, a numerical example is provided to verify the design method.

Advancements in intelligent vehicle technology have spurred extensive research into the impact of driving style (DS) on intelligent transportation systems (ITS), aiming to enhance vehicle safety, comfort, and energy efficiency. Accurate DS identification is pivotal for accelerating ITS adoption, especially in regions where its implementation is still in its infancy. This paper investigates the role of DS recognition methods, particularly clustering and classification techniques, in influencing connected vehicle control and optimizing speed planning within ITS. While traditional speed planning approaches focus on general traffic models, this study emphasizes the critical role of DS in shaping personalized and adaptive speed planning. The paper highlights three primary DS recognition approaches: rule-based, model-based, and learning-based methods, and introduces a framework for integrating DS recognition with speed planning, addressing aspects such as data collection, preprocessing, and classification techniques. This focus provides a novel perspective on leveraging DS recognition to enhance ITS adaptability.

This paper investigates finite-time (FT) stability and stabilization problems for a class of switched linear systems with polytopic uncertainties. Both stable and unstable subsystems are considered to coexist in the system, and a new concept of extended FT stability is proposed as the first attempt. A stability criterion is first established, where the admissible maximum switching number is obtained while ensuring extended FT stability of switched linear systems with time-varying delays under a given maximum ratio between the running time of unstable subsystems and the running time of stable subsystems. Sufficient conditions on the existence of desired memory state-feedback controllers are then developed. A numerical example and a class of servomechanism systems are given, respectively, to illustrate the effectiveness and validity of the developed techniques with time-varying delays and without time delay.

The performance of a number of iterative interference mitigation receivers is investigated in the context of the CDMA downlink. Two types of receiver are considered, both based on spatio-temporal filtering but differing in the way in which the filter weights are initialised in the first iteration. In the first type, the filter weights are trained directly via time-multiplexed transmitted pilots. In the second type, the weights are computed based on explicit channel estimates derived via the transmitted pilots. Least squares and semiblind (constant modulus) optimisation criteria are utilised. It is shown that, while the receivers of the second type are initialised via filter weights which do not strictly satisfy a specific optimality criterion, they do result in superior performance in subsequent iterations. The performance of the receivers is evaluated via link-level simulations involving 2- and 7-cell indoor and urban propagation environments.

Turbo-encoded multiple-input multiple-output (MIMO) radio links have been recently proposed for high-speed downlink packet access (HSDPA) in UMTS, where the reuse of spreading codes across the transmitter antennas results in high levels of interference. A state-of-the-art receiver chain for such a link incorporates space-time channel equalization, despreading, prewhitening, and detection. In this paper, the impact of modeling errors at the equalizer output on the receiver performance is investigated. Both a precise model and a more pragmatic approximate model are considered. Degradations resulting from imperfect knowledge of the channel state information at the receiver are also evaluated. The a posteriori probability (APP) detector and its max-log variant as well as the multistage partial parallel interference canceller (MS-PPIC) are examined as detection candidates in 1/3-rate and 1/2-rate coded 4/spl times/4 MIMO links. It is shown that, surprisingly, the MS-PPIC can provide superior performance compared to max-log-APP.

In this paper, the robust synchronization control for a class of chaotic systems is studied. Based on linear matrix inequality techniques and Lyapunov stability theory, a novel H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∝</sub> robust synchronization controller is designed for the possible application in real engineering. Finally, some numerical simulations are included to demonstrate the effectiveness of the proposed techniques.

This paper addresses the problem of stochastic dynamic output feedback (SDOF) stabilization for a class of stochastic continuous-time state-delayed systems with norm-bounded nonlinear uncertainties. The aim is to design a linear, delayless, and SDOF control for all admissible uncertainties. The designed control ensures stochastically exponentially stability in the mean square, independent of the deterministic time delay. Using the Finsler's lemma, the necessary and sufficient conditions for the existence of such a control are proposed in terms of certain linear matrix inequalities. These results are illustrated with a simple example to demonstrate the applicability of the proposed design approach.