There is an increasing demand for dynamic systems to become safer and more reliable This requirement extends beyond the normally accepted safety-critical systems such as nuclear reactors and aircraft, where safety is of paramount importance, to systems such as autonomous vehicles and process control systems where the system availability is vital It is clear that fault diagnosis is becoming an important subject in modern control theory and practice Robust Model-Based Fault Diagnosis for Dynamic Systems presents the subject of model-based fault diagnosis in a unified framework It contains many important topics and methods; however, total coverage and completeness is not the primary concern The book focuses on fundamental issues such as basic definitions, residual generation methods and the importance of robustness in model-based fault diagnosis approaches In this book, fault diagnosis concepts and methods are illustrated by either simple academic examples or practical applications The first two chapters are of tutorial value and provide a starting point for newcomers to this field The rest of the book presents the state of the art in model-based fault diagnosis by discussing many important robust approaches and their applications This will certainly appeal to experts in this field Robust Model-Based Fault Diagnosis for Dynamic Systems targets both newcomers who want to get into this subject, and experts who are concerned with fundamental issues and are also looking for inspiration for future research The book is useful for both researchers in academia and professional engineers in industry because both theory and applications are discussed Although this is a research monograph, it will be an important text for postgraduate research students world-wide The largest market, however, will be academics, libraries and practicing engineers and scientists throughout the world

Robust Model-Based Fault Diagnosis for Dynamic Systems

An observer for nonlinear systems is constructed under rather general technical assumptions (the fact that some functions are globally Lipschitz). This observer works either for autonomous systems or for nonlinear systems that are observable for any input. A tentative application to biological systems is described. >

A simple observer for nonlinear systems applications to bioreactors

Thermophysical Properties Research Literature Retrieval Guide Edited by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore Second edition, revised and expanded. Book 1: Pp. xxi + 819. Book 2: Pp.621. Book 3: Pp. ix + 1315. (New York: Plenum Press, 1967.) n.p.

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Heat and Mass Transfer

This paper provides a survey of modern nonlinear filtering methods for attitude estimation. Early applications relied mostly on the extended Kalman filter for attitude estimation. Since these applications, several new approaches have been developed that have proven to be superior to the extended Kalman filter. Several of these approaches maintain the basic structure of the extended Kalman filter, but employ various modifications in order to provide better convergence or improve other performance characteristics. Examples of such approaches include: filter QUEST, extended QUEST and the backwards-smoothing extended Kalman filter. Filters that propagate and update a discrete set of sigma points rather than using linearized equations for the mean and covariance are also reviewed. A twostep approach is discussed with a first-step state that linearizes the measurement model and an iterative second step to recover the desired attitude states. These approaches are all based on the Gaussian assumption that the probability density function is adequately specified by its mean and covariance. Other approaches that do not require this assumption are reviewed, Associate Professor, Department of Mechanical & Aerospace Engineering. Email: johnc@eng.buffalo.edu. Associate Fellow AIAA. Aerospace Engineer, Guidance, Navigation and Control Systems Engineering Branch. Email: Landis.Markley@nasa.gov. Fellow AIAA. Postdoctoral Research Fellow, Department of Mechanical & Aerospace Engineering. Email: cheng3@eng.buffalo.edu. Member AIAA.

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Survey of nonlinear attitude estimation methods

We present a differential geometric approach to the problem of fault detection and isolation for nonlinear systems. A necessary condition for the problem to be solvable is derived in terms of an unobservability distribution, which is computable by means of suitable algorithms. The existence and regularity of such a distribution implies the existence of changes of coordinates in the state and in the output space which induce an "observable" quotient subsystem unaffected by all fault signals but one. For this subsystem, a fault detection filter is designed.

A geometric approach to nonlinear fault detection and isolation

Simple nonlinear observers for the on-line estimation of the specific growth rate from presently attainable real-time measurements are presented. The proposed observers do not assume or require any model for the specific growth rate and they are very successful in accurately estimating this parameter. Moreover, they are very easy to implement and to calibrate. Indeed, due to the particular structure of their gain, their tuning is reduced to the calibration of a single parameter. Simulation results obtained under different operating conditions are given in order to highlight the performances of the proposed estimators.

Nonlinear observation of specific growth rate in aerobic fermentation processes

We show that the infinite-dimensional system /spl Sigma/:x/spl dot/(t)=Ax(t)+Bu(t), x/sub 0/ /spl epsiv/ H is globally strongly asymptotically stabilizable by an arbitrarily small smooth feedback. Here, the operator A is the infinitesimal generator of a C/sub 0/ semigroup of contractions e/sup tA/ on real Hilbert space H and B is a bounded linear operator mapping a Hilbert space of controls U into H. An explicit smooth feedback control law is given. Further, we identify the class of perturbations for which the system is still stabilizable by the same feedback law as for the nominal system. Based on these results and some differential Lyapunov operator equations, we then establish a global separation principle for the system /spl Sigma/ with a Kalman-like observer. Finally, these results are illustrated via an example dealing with the wave equation.

Bounded feedback stabilization and global separation principle of distributed parameter systems

The high gain observer for dynamical systems described by ordinary differential equations is widely discussed in the literature, see for instance [1], [2], [3], [4],[5], [6], [7], [8], [9], [10], [11], [12]. The aim of this paper is to extend this observer design to a class of differential-algebraic systems. In practice, the computation of solutions of differential-algebraic equations requires the combination of an ordinary differential equations (O.D.E.) routine together with an optimization algorithm. Therefore, a natural way permitting to estimate the state of such a system is to design a procedure based on a similar numerical algorithm. Beside some numerical difficulties, the drawback of such a method lies in the fact that it is not easy to establish a rigorous proof of the convergence of the observer. The main result of this paper is stated in section 3. It consists in showing that the state estimation problem for a class of differential-algebraic systems can be achieved by using an observer having an O.D.E. structure on some RN.

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A High Gain Observer for a Class of Implicit Systems

Stabilization of homogeneous bilinear systems

The synthesis of residual generators for automatic fault detection and isolation is considered. Sufficient conditions for its solvability are presented, for a particular class of nonlinear systems. The plant model is assumed to be bilinear in the control signals, up to output injection, and bilinear in the failure modes. Next a method of designing the residual generator is described. It involves the determination of a particular family of (C, A)-invariant subspaces. To this end, a characterization of all the (C, A)-invariant subspaces had to be derived. Finally, a simulation study on a distillation column model illustrates the feasibility of the approach. >

Hassan Hammouri

Papers

Nonlinear observation of specific growth rate in aerobic fermentation processes

Bounded feedback stabilization and global separation principle of distributed parameter systems

A High Gain Observer for a Class of Implicit Systems

Stabilization of homogeneous bilinear systems

Residual generator synthesis for bilinear systems up to output injection