Entwurf robuster modellbasierter Fehlerisolationsfilter

Die vorliegende Arbeit behandelt den Entwurf robuster modellbasierter Fehlerisolationsfilter für lineare zeitinvariante Systeme. Die Verfahren erlauben eine zuverlässige Lokalisierung von Fehlern auf Basis eines quantitativen Systemmodells. Zunächst wird die Dualität des Fehlerisolationsproblems zu Methoden des Entkopplungsreglerentwurfes herausgearbeitet. Auf dieser Grundlage werden Methoden zum Entwurf von Fehlerisolationsbeobachtern präsentiert. Die Robustheit der Beobachter sowohl hinsichtlich exogener Störungen als auch bezüglich unsicherer Systemparameter wird dabei unter Rückgriff auf lineare Matrixungleichungen optimiert. Schließlich werden Fehlerisolationsfilter allgemeinerer Struktur betrachtet, die gegenüber den beobachterbasierten Methoden einen vereinheitlichenden Entwurf liefern. Dieser erfolgt optimierungsbasiert und erlaubt eine einfache Auslegung, bei der lediglich intuitive Parameter einzustellen sind

Entkopplungsregelungen für lineare überaktuierte Systeme

Gegenstand des Beitrags ist der Entwurf von statischen Zustandsreglern zur Führungsentkopplung in linearen überaktuierten Systemen. Zum einen wird eine Erweiterung der Entwurfsmethodik nach Falb und Wolovich erläutert, welche eine einfache Nutzung der zusätzlichen Freiheitsgrade gegenüber klassischen Entkopplungsreglern ermöglicht. Zum anderen erlaubt ein parametrischer Entwurf die Interpretation der entstehenden Freiheitsgrade. Als Anwendungsbeispiele werden die Reduzierung der Stellenergie sowie die Steigerung der Robustheit von Entkopplungsregelungen vorgestellt

Robust fault isolation observers for non-square systems - a parametric approach

In this article, a linear matrix inequality (LMI)-based design for robust fault isolation observers (FIOs) for linear systems with arbitrary fault detectability indices is presented. A parametric design is used to achieve stable fault isolation in square systems as well as non-square systems. Based on this design, the influence of arbitrary disturbances is attenuated by a proper optimization of the observer gain matrices. The applicability of the proposed design is verified in simulations of a helicopter model

Consideration of Gyroscopic Effect in Fault Detection and Isolation for Unbalance Excited Rotor Systems

Fault detection and isolation (FDI) in rotor systems often faces the problem that the system dynamics is dependent on the rotor rotary frequency because of the gyroscopic effect. In unbalance excited rotor systems, the continuously distributed unbalances are hard to be determined or estimated accurately. The unbalance forces as disturbances make fault detection more complicated. The aim of this paper is to develop linear time invariant (LTI) FDI methods (i.e., with constant parameters) for rotor systems under consideration of gyroscopic effect and disturbances. Two approaches to describe the gyroscopic effect, that is, as unknown inputs and as model uncertainties, are investigated. Based on these two approaches, FDI methods are developed and the results are compared regarding the resulting FDI performances. Results are obtained by the application in a rotor test rig. Restrictions for the application of these methods are discussed

Robust observer-based fault detection and isolation in the standard control problem framework

This paper deals with the design of robust fault detection and isolation observers where only a single observer is employed to isolate different faults. To this end, the problem of parameterizing such observers is shown to be equivalent to designing a structurally constrained controller in the standard control problem framework. Thereby, the problem is reformulated as a well known classical control problem, which enables the use of existing tools to optimize robustness with respect to arbitrary exogenous disturbances. To account for parametric uncertainties, an approximate model matching approach is used

Master-Slave Synchronization for Nonlinear Systems based on Reduced Observers

In this article a global method for master-slave synchronization of nonlinear systems is provided. Based on a diffeomorphic transformation of the original dynamics, a reduced observer is designed such that the nonlinear state feedback law is independent of the inertial frame. Generally, the method requires non trivial computations but leads to global convergence results for the invariant tracking error. We illustrate the design procedure in detail for a master-slave synchronization of a bacterial growth model, which may escape to infinity in finite time

Effect of dietary fatty acids on expression of lipogenic enzymes and fatty acid profile in tissues of bulls

This study investigated the effects of dietary linolenic acid (C18:3n-3) v. linoleic acid (C18:2n-6) on fatty acid composition and protein expression of key lipogenic enzymes, acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase (SCD) and delta 6 desaturase (6d) in longissimus muscle and subcutaneous adipose tissue of bulls. Supplementation of the diet with C18:3n-3 was accompanied by an increased level of n-3 fatty acids in muscle which resulted in decrease of n-6/n-3 ratio. The diet enriched with n-3 polyunsaturated fatty acids (PUFAs) significantly inhibited SCD protein expression in muscle and subcutaneous adipose tissue, and reduced the 6d expression in muscle. There was no significant effect of the diet on ACC protein expression. Inhibition of the 6d expression was associated with a decrease in n-6 PUFA level in muscles, whereas repression of SCD protein was related to a lower oleic acid (C18:1 cis-9) content in the adipose tissue. Expression of ACC, SCD and 6d proteins was found to be relatively higher in subcutaneous adipose tissue when compared with longissimus muscle. It is suggested that dietary manipulation of fatty acid composition in ruminants is mediated, at least partially, through the regulation of lipogenic enzymes expression and that regulation of the bovine lipogenic enzymes expression is tissue specific. © 2010 The Animal Consortium