Letteratura scientifica selezionata sul tema "H1/H∞ filter"

AbstractIn this paper, we introduce the notion of state maps from a semihoop H1 to another semihoop H2, which is a generalization of internal states (or state operators) on a semihoop H. Also we give a type of special state maps from a semihoop H1 to H1, which is called internal state maps (or IS-maps). Then we give some examples and basic properties of (internal) state maps on semihoops. Moreover, we discuss the relations between state maps and internal states on other algebras. Then we introduce several kinds of filters by state maps on semihoops, called SM-filters, state filters and dual state filters, respectively, and discuss the relations among them. Furthermore we introduce and study the notion of prime SM-filters on semihoops. Finally, using SM-filter, we characterize two kinds of state semihoops.

This paper proposed three methods to compensate the temperature energy influence drift of the MEMS vibration gyroscope, including radial basis function neural network (RBF NN), RBF NN based on genetic algorithm (GA), and RBF NN based on GA with Kalman filter (KF). Three-axis MEMS vibration gyroscope (Gyro X, Gyro Y, and Gyro Z) output data are compensated and analyzed in this paper. The experimental results proved the correctness of these three methods, and MEMS vibration gyroscope temperature energy influence drift is compensated effectively. The results indicate that, after RBF NN-GA-KF method compensation, the bias instability of Gyros X, Y, and Z improves from 139°/h, 154°/h, and 178°/h to 2.9°/h, 3.9°/h, and 1.6°/h, respectively. And the angle random walk of Gyros X, Y, and Z was improved from 3.03°/h1/2, 4.55°/h1/2, and 5.89°/h1/2to 1.58°/h1/2, 2.58°/h1/2, and 0.71°/h1/2, respectively, and the drift trend and noise characteristic are optimized obviously.

The optical filter under development employing frustrated total internal reflection is a micromechanical device containing two silicon rectangular prisms. There is flat silicon plane among hypotenuse edges of the prisms. The silicon plane is a Fabry-Perot resonator, with clearances h1 among the plate and prism edges being its mirrors. Theoretical resolution of the optical filter would be R ≈ 1,5∙103 if h1 = 50 µm and R ≈ 3∙105 if h1 = 100 µm with the thickness of the silicon plane being h = 65 µm; wavelength λ = 100 µm; free spectral region Δλ/λ ≈ 0,3…0,4, transmission in the maximum of spectral characteristics 0,6 (provided input and output silicon prism legs bloom).

Abstract This paper deals with the problem of robust fault detection (FD) for an unmanned aerial vehicle (UAV) flight control system (FCS). A nonlinear model to describe the UAV longitudinal motions is introduced, in which multiple sources of disturbances include wind effects, modeling errors and sensor noises are classified into groups. Then the FD problem is formulated as fault detection filter (FDF) design for a kind of nonlinear discrete time varying systems subject to multiple disturbances. In order to achieve robust FD performance against multiple disturbances, simultaneous disturbance compensation and H1/H∞ optimization are carried out in designing the FDF. The optimality of the proposed FDF is shown in detail. Finally, both simulations and real flight data are applied to validate the proposed method. An improvement of FD performance is achieved compared with the conventional H1/H∞-FDF.

The aim of this study is to compare the microhardness of five different low-viscosity bulk-fill composites. The bulk-fill composites used in the study; Estelite Bulk-fill flow (EBF), Filtek Bulk-fill (FBF), SureFil SDR flow (SDR), Tetric EvoFlow Bulk fill (TEFBF), X-tra Base (XBF). Cylindrical molds with a diameter of 5 mm and a height of 4 mm were used for the Vicker's Micro Hardness (VMH) test. Bulk-fill composite resins were placed in these molds at once. The polymerization of the composites was achieved for 20 seconds with the LED light curing. A total of 50 composite discs were prepared (n=10). Then the microhardness of the top and bottom surfaces was measured using MVK-H1 Microhardness Tester (Akashi Co, Tokyo, Japan. Depth of polymerization of each sample was recorded. Data were analyzed by using the Kruskal Wallis H and Mann Whitney-U tests. The bottom and top surface hardness values of the XBF composite samples (43.82±0.95 MPa, 47.87±0.59 MPa) were statistically significantly higher than the other bulk-fill composite samples (p<0.001). The bottom and top surface hardness values of the FBF composite (27.85±0.56 MPa, 22.05±1.40 MPa) were found to be statistically lower than other bulk-fill composite samples (p<0.001). Among the low-viscosity bulk-fill composites used in the study, except for FBF, the VMH values of the others were found to be above 0.80, and it was observed that they reached sufficient microhardness.

Les travaux présentés dans ce mémoire de thèse visent à développer de nouvelles approches basées sur une nouvelle classe particulière d’estimateurs d´état : les filtres dits par intervalles. Tout comme la classe des observateurs intervalles, l’objectif est d’estimer les bornes supérieures et inférieures des états d’un système, à chaque instant de temps. L’approche proposée repose sur la théorie des systèmes monotones et sur la connaissance a priori du domaine d’appartenance, supposé borné, des incertitudes de modèle et des entrées exogènes (perturbations, bruit de mesure, etc). L’élément clé de l’approche proposée repose sur l’utilisation de filtre d’ordre quelconque, sans structure a priori fixée, plutôt qu’une structure basée sur l’observateur (reposant uniquement sur une structure dynamique du système étudié). La synthèse des paramètres du filtre repose sur la résolution d’un problème d’optimisation sous contraintes de type inégalités matricielles linéaires et bilinéaires (LMI et BMI) permettant de garantir simultanément les conditions d’existence du filtre ainsi qu’un niveau de performance, soit dans un contexte énergie, soit dans un contexte amplitude ou soit dans un contexte mixte énergie/amplitude. La méthodologie de synthèse proposée est illustrée sur un exemple académique et est comparée avec d’autres méthodes existantes dans la littérature. Enfin, la méthodologie est appliquée au cas du contrôle d’attitude et d’orbite d’un satellite, sous des conditions de simulations réalistes
The work of this thesis aims at developing new approaches based on a new particular class of state estimators, the so-called interval or ensemble filters.Like the class of interval observers, the objective is to estimate, in a guaranteed way, the upper and lower bounds of the states of a system, at each time instant.The proposed approach is based on the theory of monotonic systems and on the knowledge of the domain of membership, supposedly bounded, of the uncertainties of the system, such as disturbances, noise and bias of sensors, etc.The key element of the proposed approach is to use a filter structure advantage, rather than an observer-based structure (relying only on a dynamic structure of the studied system).The synthesis of the filter parameters is based on the resolution of a constrained optimization problem of linear and bilinear matrix inequalities (LMI and BMI) allowing to guarantee simultaneously the existence conditions of the filter as well as a performance level, either in an energy context for LTI systems, or in an amplitude context or in a mixed energy/amplitude context for LPV systemsThe proposed synthesis methodology is illustrated on an academic example and is compared with other existing methods in the literature. Finally, the methodology is applied to the case of attitude and acceleration control of a satellite, under realistic simulation conditions