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International audience; The main contribution of this paper is a robust integrated design of proportional - integral (PI) observer and state-feedback controller for uncertain linear parameter-varying (LPV) system. In this design, both fault estimation and robust feedback stabilization are developed. Moreover, since the state-feedback controller is derived from the PI observer, the loop transfer recovery (LTR) properties can be designed to maximize the closed-loop performance. Meanwhile, the PI observer and controller gains are simultaneously obtained from a linear matrix inequality (LMI), which is inferred from estimation errors, Young equality and majorization lemma implementation. Finally, its application to a vehicle suspension platform is presented to highlight the performances of the developed method.

International audience; The main contribution of this paper consists of the development of two methods for actuator fault estimation in dealing with the partially decoupled disturbances of the descriptor system, which is divided into decoupled and non-decoupled unknown inputs (UI). Based on the conventional UI observer, both of the solutions decouples the fault estimation with the first group of UI, while the second UI group is handled differently by each method. Finally, a numerical example with comparisons points out the performance of each approach.

International audience; The main contribution of this article is a new methodology of a polytopic observer-based controller in estimating and accommodating polynomial actuator degradation for uncertain stochastic linear parameter varying system. In this design, robust observer-based controller gains are synthesized with a unique linear matrix inequality solution such that the impact of disturbance on observer estimation is attenuated by a frequency-shaping filter, while ensuring the closed-loop stability against system uncertainties and stochastic noise. Finally, an example is illustrated to highlight the performance of the proposed method.

The main contribution of this paper is a H ∞ observer design for a new class of general singular Nonlinear Parameter-varying system in the presence of disturbances and Lipschitz nonlinearity. In specific, this observer tackles the impact of disturbance on estimation error thanks to the H ∞ norm, while the robust parameter-dependent stability of estimation dynamics helps to widen the feasible region of LMI solution under the Lipschitz constraint. Finally, a numerical example with the gridding solution is illustrated to highlight the proposed design.

The main contribution of this paper is the design of robust $\mathcal{H}_{\infty}$ proportional-integral (PI) observer for fault detection, isolation and magnitude estimation, applied for uncertain linear time-invariant (LTI) system. It is based on a combination of PI observer and $\mathcal{H}_{\infty}$ norm in order to deal with system uncertainty and disturbance attenuation. This multi-objective problem is tackled by the solution of linear matrix inequality (LMI) feasibility problem, obtained from the analysis of estimation errors and the use of majoration lemma. The application to a real suspension system is then presented to highlight the performances of the proposed observer.

The main contribution of this paper is a robust $\mathscr{H}_{2}$ observer design to estimate the actuator degradation under the influence of disturbances and parametric uncertainty. In this design, the observer conception, based on the $\mathscr{H}_{2}$ frequency-shaping filter and theorem of Parseval, allows the estimation of degradation in polynomial form while coping with system uncertainty. Moreover, the usage of the proposed method also relaxes the conditions for unknown input observer (UIO) or the min-max optimization in linear matrix inequality (LMI) for the disturbance attenuation, which facilitates the robust observer design by engineers. Finally, an application to suspension system is presented to illustrate the performance of the proposed method.

Composites of carbon nanotubes – titanate nanotubes (MWNTs/ TNTs) – were successfully synthesized by the hydrothermal reaction process. The morphology of the MWNTs/TNTs composites was observed by transmission electron microscopy. Fourier transform infrared spectroscopy was used to characterize the molecular interactions between TNTs and MWNTs in the composites. The X-ray diffraction of TNTs and MWNTs/TNTs composites exhibited the existence of titanate phase (100), (102), (020) and (422). The charge recombination of MWNTs/TNTs composites was examined by photoluminescence spectrum. The photocatalytic activity of TNTs and MWNTs/TNTs composites was evaluated on the basis of the model oxidation reaction of H2S.

The main contribution of this paper is an integrated design of robust fault estimation (FE) and fault accommodation (FA), applied to uncertain linear time invariant (LTI) systems. In this design, the robust $\mathscr{H}_{\infty}$ proportional-integral (PI) observer allows a precise estimation of actuator fault by dealing with system disturbances and uncertainties, while the feed-back controller compensates the actuator fault, and therefore assuring the closed-loop stability. Thanks to the application of majoration and Young inequalities, the observer-controller decoupling problem is solved and both above objectives are combined into only one linear matrix inequalities (LMI) allowing a simultaneous solution for both observer and controller. Finally, an example of vehicle suspension system is illustrated to highlight the performance of the proposed method.

A nanopowder of iron was prepared using a high-energy ball milling method, which is capable of producing nanoparticles at a reasonably larger scale compared to conventional chemical methods. Analyses using x-ray diffraction and magnetic measurements indicate that the iron nanoparticles are a single phase of a body-centered cubic structure and have quite stable magnetic characteristics in the air. The iron nanoparticles were then mixed with paraffin and pressed into flat square plates for free-space microwave transmission and reflection measurements in the 4–8 GHz range. Without an Al backing plate, the Fe nanoparticles seem to only weakly absorb microwave radiation. The reflected signal S 11 drops to zero and a very large negative value of reflection loss (RL) are observed for Al-backed samples, suggesting the existence of a phase matching resonance near frequency f ∼ 6 GHz.