Showing papers by "Paul M. Frank published in 2001"

Modelling for Fault Detection and Isolation versus Modelling for Control

Abstract: The main purpose of this paper is to emphasize the particularities of models needed for model-based fault detection and isolation (FDI) in contrast to the models used for control. Of special interest is the question of complexity of the model, which is of great importance for the practical implementation. This, of course, depends basically on the given situation such as the kind of plant, the measurements, the kind and number of faults to be detected and the demands for fault isolation and robustness. However, the paper shows that diagnostic models, in contrast to the wide-spread opinion that those have always to be more complex than the functional models for control, may be even less complex, because they are restricted to only those parts of the system in which the faults occur. The issue of model complexity is discussed in terms of different model-based FDI approaches analytical, knowledge-based and data-based. The ideas are illustrated in a case study, where several types of model-based FDI techniques...

Finite dimensional variable structure control design for distributed delay systems

Abstract: A general design method for the variable structure control of distributed time-delay systems is studied in this paper. The proposed switching function and variable structure controller are of finite dimension. The basic idea is to construct a finite dimensional system which contains all the unstable poles of the original time-delay system and hence those unstable poles of the time delay system will be absorbed by the developed variable structure controller. The proposed method is applied to the stabilization of combustion in a liquid monopropellant rocket motor and satisfactory results are obtained by simulation study. Simulation results show that the developed variable structure controller can still stabilize the combustion when the two key parameters, pressure exponent and maximal time lag r, change from their nominal value down to 0.0 and 0.1 respectively. By this result, we can somewhat overestimate the two parameters to obtain a reliable controller for the rocket motor control systems.

Three—tank Control Reconfiguration

Abstract: This chapter describes benchmark problem for controller reconfiguration. It is based on a laboratory process consisting of tanks with fluid flow. Many schemes for controller reconfiguration have been investigated and compared.

System identification and fault diagnosis using dynamic functional-link neural networks

Abstract: The paper investigates the application of new neural networks with internal dynamics to Fault Detection and Isolation (FDI). The suggested dynamic functional-link structures are used to design efficiently different neural observes schemes by means of system identification. Structured sets of residuals are thus generated based on the one-step ahead prediction errors. A first case study refers to the component FDI of a three-tank laboratory system. A second investigation concerns the sensor FDI of an evaporator sub-process from a sugar factory. In both experimental applications, static neural networks are used to classify the generated symptoms.

Residual Generation for FDI in Non-linear Systems

Abstract: Most results on fault detection and isolation have been developed using linear models. This chapter deals with fault detection in nonlinear systems. Particular attention is given to generation of residuals. Both algebraic and geometric methods are used.