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> filtering problem of discrete-time switched linear systems in sensor networks in face of packet dropouts and quantization. Specifically, due to the packet dropout phenomenon, the filters may lose access to the real-time switching signal of the plant. It is assumed that the maximal packet dropout number of switching signal is bounded. Then, a distributed filtering system is proposed by further considering the quantization effect. Based on the Lyapunov stability theory, a sufficient condition is obtained for the convergence of filtering error dynamics. The filter gain design is transformed into a convex optimization problem. In this paper, a quantitative relation between the switching rule missing rate and filtering performance is established. Furthermore, the upper bound of the switching rule missing rate is also calculated. Finally, the effectiveness of the proposed filter design is validated by a simulation study on the pulse-width-modulation-driven boost converter circuit. The impact of noise covariance, system dynamics, and network connectivity is studied, and some discussions are presented on how these parameters affect the filtering performance.
In this work, a systematic strategy to design passive damping systems for structural vibration control is presented. The proposed design methodology is based on the equivalence between decentralized static velocity-feedback controllers and passive damping systems. By using recent developments in static output-feedback control, the design of passive-damping systems can be formulated as a single optimization problem with Linear Matrix Inequality constraints. Moreover, this optimization problem can be efficiently solved with standard numerical tools, even for large dimension systems. Due to its computational effectiveness, the proposed methodology can be applied to the design of passive damping systems for large structures. To illustrate the main ideas and methods, a passive damping system is designed for the seismic protection of a five-story building with excellent results.
In this paper, the stability problem is studied for a class of Markovian jump neutral nonlinear systems with time-varying delay.By Lyapunov-Krasovskii function approach, a novel mean-square exponential stability criterion is derived for the situations that the systems transition rates are completely accessible, partially accessible and non-accessible, respectively.Moreover, the developed stability criterion is extended to the systems with different bounded sector nonlinear constraints.Finally, some numerical examples are provided to illustrate the effectiveness of the proposed methods.
No abstract is provided for this article.
This chapter addresses the problem of leader-following exponential consensus in fractional-order descriptor nonlinear multi-agent systems through the design of an event-triggered sliding mode control strategy. Exponential consensus is achieved by defining an appropriate sliding surface and a controller, ensuring Mittag-Leffler stability for fractional-order systems. Due to the inherent memory property of the fractional-order calculus operator, a novel condition is established to prevent the occurrence of Zeno behavior, distinguishing this approach from existing event-triggered schemes. This new condition is crucial for maintaining practical implementability and system reliability. To demonstrate the effectiveness and feasibility of the proposed method, two illustrative examples are provided, showcasing the robustness and applicability of the strategy in achieving desired consensus among agents. These examples highlight the practical implications and advantages of the developed control approach in handling complex dynamics in multi-agent systems.
Considering that state distribution obeys a generalized Gaussian distribution, it cannot be accurately estimated using only the mean error criterion or mean square error criterion. Therefore, this brief addresses the high-order moment filter design problem for Markov jump systems in the finite frequency domain. An estimation method is applied by transforming the original stochastic system into a high-order component form via the cumulant generating function. Then, the generalized Kalman-Yakubovic-Popov lemma can be used in filter design, by considering finite frequency characteristics. Sufficient conditions for the existence of a high-order moment filter with the required finite frequency performance are established. Finally, a simulation example is presented to verify the effectiveness of the proposed method.
Some artificial intelligence algorithms have gained much attention in the rotating machinery fault diagnosis due to their robust nonlinear regression properties. In addition, existing deep learning algorithms are usually dependent on single signal features, which would lead to the loss of some information or incomplete use of the information in the signal. To address this problem, three kinds of popular signal processing methods, including Fast Fourier Transform (FFT), Short-Time Fourier Transform (STFT) and directly slicing one-dimensional data into the two-dimensional matrix, are used to create four different datasets from raw vibration signal as the input data of four enhancement Convolutional Neural Networks (CNN) models. Then, a fuzzy fusion strategy is used to fuse the output of four CNN models that could analyze the importance of each classifier and explore the interaction index between each classifier, which is different from conventional fusion strategies. To show the performance of the proposed model, an artificial fault bearing dataset and a real-world bearing dataset are used to test the feature extraction capability of the model. The good anti-noise and interpretation characteristics of the proposed method are demonstrated as well.
This chapter introduces the structural control concept for load reduction of OWTs. Theories for both passive and active structural control are introduced. Particularly, a spar-type FOWT is used as the study case to demonstrate the load mitigation effectiveness of the proposed structural control methods. For the passive case, design optimization process is performed on a TMD installed in the spar platform, and the obtained numerical simulation results have indicated the both their effectiveness and limits regarding different system parameters and installations. Regarding the active case, a gain scheduling H2/H∞ active structural full-state feedback controller is designed for an HMD installed at the tower top of a spar-type FOWT, aiming at both reducing tower bottom load and mitigating the aerodynamic disturbance. The results demonstrate that more load reduction could be achieved at the expense of more energy consumption. At the same time, this will bring the risk of instability. Moreover, the full-state feedback controller is not very practical from a technical point of view due to the lack of sensors and measurement inaccuracy.
This paper is concerned with the problem of dynamic output feedback (DOF) control for a class of uncertain discrete impulsive switched systems with state delays and missing measurements. The missing measurements are modeled as a binary switch sequence specified by a conditional probability distribution. The problem addressed is to design an output feedback controller such that for all admissible uncertainties, the closed-loop system is exponentially stable in mean square sense. By using the average dwell time approach and the piecewise Lyapunov function technique, some sufficient conditions for the existence of a desired DOF controller are derived, then an explicit expression of the desired controller is given. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.
This report considers attempts to develop dummy motorcyclists with breakable legs. Material characteristics are discussed. The variation in the scatter fracture load of different materials is compared using the Weibull modulus. The materials used in the different dummy legs have been calibrated statically and uni-axially whereas in crash tests multi-axial dynamic loads are sustained. The Independent Action criterion is used to show that: (1) compressive and torsion loads have only a small effect on bending; and (2) differences in results from different laboratories is the result of scatter in the material characteristics. The effect that leg fracture has on dummy trajectory is described using previously published experimental pedestrian impacts, motorcycle crash tests and pedestrian and car occupant computer simulation studies. Head trajectory is shown to be largely unaffected by leg fracture. For the covering abstract of the conference see IRRD 864606.
