Publications

This paper investigates the problem of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:msub><mml:mi>ℋ</mml:mi><mml:mi>∞</mml:mi></mml:msub></mml:mrow></mml:math>state-feedback control for a class of two-dimensional (2D) discrete-time Markovian jump linear time-delay systems with defective mode information. The mathematical model of the 2D system is established based on the well-known Fornasini-Marchesini local state-space model, and the defective mode information simultaneously consists of the exactly known, partially unknown, and uncertain transition probabilities. By carefully analyzing the features of the transition probability matrices, together with the convexification of uncertain domains, a new<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mrow><mml:msub><mml:mi>ℋ</mml:mi><mml:mi>∞</mml:mi></mml:msub></mml:mrow></mml:math>performance analysis criterion for the underlying system is firstly derived, and then the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mrow><mml:msub><mml:mi>ℋ</mml:mi><mml:mi>∞</mml:mi></mml:msub></mml:mrow></mml:math>state-feedback controller synthesis is developed via a linearisation technique. It is shown that the controller gains can be constructed by solving a set of linear matrix inequalities. Finally, an illustrative example is provided to verify the effectiveness of the proposed design method.

This paper investigates the problem of robust fault detection system design for a class of uncertain Takagi–Sugeno (T–S) models. The system under consideration is subject to unknown input and time-varying delay. The fault detection system is designed such that the unknown input is thoroughly decoupled from residual signals generated by the fault detection system. Furthermore, the residual signals show the maximum possible sensitivity to the faults and the minimum possible sensitivity to the external disturbances. The model matching approach is utilized to tackle the effects of parametric uncertainties in the model of the system. The design procedure is presented in terms of Linear Matrix Inequalities (LMIs). Some remarks are given to analyze the proposed method. Finally, a numerical example is presented to show the effectiveness of the proposed method.

This article investigates the stability issue for a class of switched nonlinear systems whose control inputs include time delay and sampling. It is assumed that a stabilizing controller is predesigned for the nominal system such that it is stable under a certain switching signal. However, in the presence of input delay and sampling, the system may not be stable under the same stability criteria. Besides, the switching signals are discussed in two cases, that is, the switching signal of the system is transmitted to the controller in real time and only the sampled information of the switching signal is available to the controller at each sampling instant. For the latter, the asynchronous motions between the subsystems and the candidate controllers are caused and the closed‐loop system is rewritten as sampled switched nonlinear delay system with an augmented switching signal. By constructing sampling interval‐dependent Lyapunov–Krasovskii functional and using the theory of the asynchronous switched delay system, we establish the stability conditions on the switching signal which depends on the size of the delay, the upper bound of the sampling interval, and the dwell time. Finally, a numerical example is given to illustrate the effectiveness of the proposed results.

In this article, the issue of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathscr {L}_{1}$ </tex-math></inline-formula> control design is addressed for a class of delayed stochastic jump systems subject to semi-Markov jump parameters. The stochastic jump systems in the presence of positivity constraints are described by positive semi-Markov jump systems (S-MJSs). By constructing new linear Lyapunov functional dependent double integral, some sojourn-time-dependent sufficient conditions are established to realize the corresponding stochastic stability with a prescribed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathscr {L}_{1}$ </tex-math></inline-formula> -gain performance index. Then, a switching controller via gain matrix decomposition is designed to achieve positivity and stochastic stabilization with a prescribed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathscr {L}_{1}$ </tex-math></inline-formula> -gain performance, which can be solved with the help of linear programming approach. Finally, the virus mutation treatment model verifies the effectiveness of the theoretical results.

No abstract is provided for this article.

For wind turbine load mitigation, this paper proposes an active structural control deign of a hybrid mass damper installed at the tower top of a spar-type floating wind turbine. System dynamic model is established based on first principles and the polynomial curve fitting approach, while different steady-state points are derived. Then, a gain scheduling H2/H ∞ state feedback controller is designed by solving linear matrix inequalities, which aims to reduce the loading. At last, nonlinear simulations are performed under different wind and wave conditions, and the results demonstrate that more load reduction could be achieved at the expense of more energy consumption in mass damper actuator.

This paper deals with the modeling and parameter tuning of a spar-type floating wind turbine with a tuned mass damper (TMD) installed in nacelle. Firstly, a mathematical model for the system surge-heave-pitch motion is established based on first principles. Secondly, different parameter tuning methods are adopted to find the optimal TMD parameters for load reduction. Thirdly, nonlinear wind turbine simulations with different designs are conducted under different wind and wave conditions. The results show that TMD with small spring and damping coefficients will help to produce much load reduction in above rated condition. However, it may deteriorate system performance when the turbine is working below rated. In contrast, the design with large spring and damping constants will achieve moderate load reduction in both working conditions.

1Department of Engineering, Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway 2College of Engineering, University of Wisconsin System, Madison, WI, USA 3ArcelorMittal Bremen GmbH, Bremen, Germany 4BIBA-Bremer Institut fur Produktion und Logistik GmbH, Planning and Control of Production Systems (PSPS), University of Bremen, Hochschulring 20, 28359 Bremen, Germany 5University of Picardie Jules Verne, MIS-UPJV, 7 Moulin Neuf, 80000 Amiens, France

This chapter addresses the Mittag-Leffler projective synchronization problem of fractional-order coupled systems (FOCS) on complex networks without strong connectedness by employing fractional sliding mode control (SMC). By integrating the hierarchical algorithm with graph theory, a novel SMC strategy is devised to achieve projective synchronization between the master and slave systems. This strategy encompasses both global complete synchronization and global antisynchronization, thereby providing a comprehensive solution for various synchronization scenarios. Additionally, new criteria are derived to ensure the Mittag-Leffler stability of the projective synchronization error system, offering robust theoretical guarantees for the proposed approach. Finally, a numerical example is provided to demonstrate the validity and effectiveness of the proposed method, highlighting its potential applications in complex network systems and its superiority in handling fractional-order dynamics.

In this paper we present the application of regressive models to simulation of car-to-pole impacts. Three models were investigated: RARMAX, ARMAX and AR. Their suitability to estimate physical system parameters as well as to reproduce car kinematics was examined. It was found out that they not only estimate the one quantity which was used for their creation (car acceleration) but also describe the car’s acceleration, velocity and crush. A virtual experiment was performed to obtain another set of data for use in further research. An AR model to predict the behavior of a low-speed car impacting a rigid barrier was created and verified.

No abstract is provided for this article.

Sub-optimal multi-user joint-detection (JD) is an effective technique for combating the effects of multiple-access interference in CDMA communication systems. Its implementation, however, is accompanied by a prohibitive computational complexity when supporting large numbers of asynchronous users and channels with long impulse responses. Two approaches for the reduction of this complexity are compared. The first is based on an approximate Cholesky factorization. The second is based on iterative schemes such as the method of conjugate gradients or the Jacobi algorithm and its derivatives. The two approaches result in significant reductions in complexity at the expense of little or no degradation in performance. Results are presented for the asynchronous multi-rate environment of the WCDMA uplink with exact and realistic channel estimates.

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.

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.