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Robust finite-time (FT) stabilization of uncertain continuous-time singular systems is of concern in this paper. By adopting a Lyapunov-like functional (LLF) and the finite-time stability (FTS) technique, the linear matrix inequality (LMI)-based conditions are derived for uncertain continuous-time singular systems to be stabilizable. Then, based on solving these LMIs, a FT H-infinite state feedback...
Derivation of signals is often required to control various dynamic objects [1–8]. Derivation allows increasing the stability of the system, since it allows to react not only to the actual increase in the control error, but also to take into account the tendency of growth or reduction of this error. Derivation increases the margin of stability in phase. There are methods of designing regulators based...
This paper focuses on the small-signal stability analysis of systems modeled as Neutral Delay Differential Equations (NDDEs). These systems include delays in both the state variables and their first time derivatives. The proposed approach consists in descriptor model transformation that constructs an equivalent set of Delay Differential Algebraic Equations (DDAEs) of the original NDDE. The resulting...
Unknown delayed systems are present in many domains and control this kind of systems remains a difficult problem. Indeed, we can find theses systems in physics, chemistry, aeronautics, etc. The main problem is that the delay is unknown, and so the model is not exactly well-known. By the way, the use of model-free control (MFC) remains a suitable solution to tackle this problem. This paper deals with...
In this paper, we investigate the sampled-data control problem for polynomial sampled-data fuzzy system with time-varying delay. Based on sampled-data technique, a fuzzy controller is designed to guarantee the stability of closed-loop polynomial fuzzy system. By examining the stabilization problem, the Lyapunov-Krasovskii functional (LKF) is adopted and a delay-dependent stabilization condition is...
Hybrid feedback control systems are constructed after replacing the continuous controllers with neural-network controllers (in term of neural algorithms). Here, the continuous controllers are originally designed by using the control theory in the linear time-invariant (LTI) continuous-time setting, while the neural algorithms approximate the input/output behavior of the continuous controllers through...
The finite-time stabilization for a class of stochastic nonlinear systems with Markovian switching and uncertain transition probabilities is studied in this paper. Different from existing results for stochastic systems with Markovian switching which are all about strong solutions, the results in this paper are about weak solutions. Firstly, we develop Lyapunov theorems for the existence of a global...
With the aim of increasing the numerical methods' precision regarding Maxwell's equations solving, a third order staggered FDTD method is proposed in this paper. The proposed method offers a trade-off between the accuracy and the stability, through the application of a third order staggered backward differentiation for the approximation of the temporal partial derivatives, and a fourth-order central...
Because of the significant increase in size and complexity of the networks, the distributed computation of eigenvalues and eigenvectors of graph matrices has become very challenging and yet it remains as important as before. In this paper we develop efficient distributed algorithms to detect, with higher resolution, closely situated eigenvalues and corresponding eigenvectors of symmetric graph matrices...
In the digital society, information, communication and control technologies are realized based on a packet of signals (or a finite number of data). That is, control systems are operated by discretized/quantized signals not only in the time domain but also in the spatial domain (state space). In this paper, the stability of such (nonlinear) discrete dynamical systems is analyzed based on multiple metrics...
Power electronic converters are today an essential part of the electrical power systems, employed to improve the system performance and enhance its stability. At the same time, the introduction of power converters might negatively affect the overall dynamic behaviour of the power system. System stability can be investigated from different perspectives, e.g. time-domain observation, eigenvalue analysis,...
The stability of grid-connected modular multilevel converter (MMC) under two control strategies is studied in this paper. For this purpose, the ac-side input admittance of the MMC is derived under open- and closed-loop ac-side control strategies. The derived analytical models are used to investigate the impact of the two approaches on the stability of the MMC and detailed time-domain simulations are...
Under specific conditions, Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) systems can experience stability, or poor-damping related issues. Analytical investigation of the system eigenvalues can demonstrate the impact of physical or control parameters on the system stability. However, especially in case of high-order systems, such expressions are challenging to obtain and so...
This paper investigates and offers some stability analysis methods for systems of non-integer orders. Well known analysis methods such as Hurwitz, interlacing property, monotonic phase increment property are reconsidered in a fractional order way of thinking. A method to find the roots of the so-called fractional order polynomials is proposed and Hurwitz-like stability of the pseudo-polynomials is...
The finite difference time domain method (FDTD) is widely used in solutions of electromagnetic problems, but has as a condition of stability, the Courant-Friedrich-Levy (CFL), that limits the step time to be used. The method has a high computational processing time and memory usage in three-dimensional analysis for electromagnetic cavities due to the high number of resonance frequencies to be simulated,...
Power systems can be stabilized using distributed control methods with wide-area measurements for feedback. However, wide-area measurements are subject to time delays in communication, which can have undesirable effects on system performance. We present time-domain analysis results regarding the small-signal stability of a two-area power system with damping control subjected to asymmetric time delays...
A three-dimensional slope stability problem involving a spherical failure surface in clay is often used in the literature as a benchmark example against which numerical models are validated. In the existing research literature, the analytical expression has been obtained for the factors of safety by assuming plane-strain mechanisms during slope failure. And the hypothesis does not comply with the...
In most distributed power electronic systems, the transmission line effects associated with cabling are neglected due to the expectation that cables are sufficiently short to be modeled as a lumped parameter model. However, as converter switching speeds and control bandwidth increase, especially in large distributed power electronic based systems, the transmission line effects may become an important...
In this work, we study the string stability properties of a leader following formation control architecture that uses non homogeneous weights for the leader and predecessor vehicle states. The architecture was presented recently [1] and it was shown to achieve constant inter-vehicle spacings (with no transient) for almost every vehicle pair when there are no disturbances at the followers. We expand...
The stability of time-invariant positive nonlinear systems is addressed. Necessary conditions for the stability of positive time-invariant continuous-time and discrete-time nonlinear systems are established. It is shown that the positive nonlinear systems are asymptotically stable only if the corresponding positive linear systems are asymptotically stable. Considerations are illustrated by numerical...
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