Michel Kinnaert

Conditioning technique, a general anti-windup and bumpless transfer method

Abstract This paper gives a general way to take into account, by an appropriate design of the controller, any discrepancy which can occur between the actual inputs of a process and the desired outputs of its controller. This yields to the so-called conditioned control algorithms. The conditioning technique is described for multiple-input-multiple-output nonlinear controllers. Application to complex control structures is explained. The notion of a self-conditioned controller is defined in order to simplify the implementation of the conditioning technique. Some considerations about the stability of conditioned systems are given. The automatic initialization of any control algorithm is given as an application of the method. It shows that bumpless transfer can be achieved.

Observer-based approach to fault detection and isolation for nonlinear systems

The design of a residual generator for fault detection and isolation (FDI) in nonlinear systems which are affine in the control signals and in the failure modes is studied, First, the problem statement used for linear systems is extended, and a set of sufficient conditions for the existence of a solution is given. Next, circumstances under which high-gain observers for uniformly observable systems can be used in the synthesis of the residual generator are provided.

Fault tolerant control of wind turbines: a benchmark model

Abstract The installed energy generation capacity of wind turbines is increasing dramatically on a global scale; this means that reliability of wind turbines is of higher importance. A part of this task is to improve fault detection and accommodation schemes of the wind turbine. This paper presents a benchmark model for simulation of fault detection and accommodation schemes. This benchmark model deals with the wind turbine on a system level containing sensors, actuators and systems faults in the pitch system, drive train, generator and converter system.

Fault-Tolerant Control of Wind Turbines: A Benchmark Model

This paper presents a test benchmark model for the evaluation of fault detection and accommodation schemes. This benchmark model deals with the wind turbine on a system level, and it includes sensor, actuator, and system faults, namely faults in the pitch system, the drive train, the generator, and the converter system. Since it is a system-level model, converter and pitch system models are simplified because these are controlled by internal controllers working at higher frequencies than the system model. The model represents a three-bladed pitch-controlled variable-speed wind turbine with a nominal power of 4.8 MW. The fault detection and isolation (FDI) problem was addressed by several teams, and five of the solutions are compared in the second part of this paper. This comparison relies on additional test data in which the faults occur in different operating conditions than in the test data used for the FDI design.

Fault diagnosis based on analytical models for linear and nonlinear systems - a tutorial

Abstract The diagnosis systems considered in this paper rely on the inconsistency between the actual process behaviour and its expected behaviour as described by an analytical model. The inconsistency is exhibited in signals called residuals. Two methods for residual generation are presented in a tutorial way: the parity space and the observer based approaches. Linear and nonlinear models are successively considered as a basis for the design of the residual generators.

Brief Paper: Robust fault detection based on observers for bilinear systems

The design of a residual generator for robust fault detection in bilinear systems is considered. Two methods are presented. The first one is based on a linear time-invariant observer up to output injection while the second one relies on a so-called Kalman-like observer. It is shown via examples that the approach based on a Kalman-like observer allows one to handle a larger class of bilinear systems than the other observer-based methods presented in the literature.

Diagnosis and Fault-tolerant Control, 2nd edition

Fault-tolerant control aims at a gradual shutdown response in automated systems when faults occur. It satisfies the industrial demand for enhanced availability and safety, in contrast to traditional reactions to faults, which bring about sudden shutdowns and loss of availability. The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process that can be used to ensure fault tolerance. It also introduces design methods suitable for diagnostic systems and fault-tolerant controllers for continuous processes that are described by analytical models of discrete-event systems represented by automata. The book is suitable for engineering students, engineers in industry and researchers who wish to get an overview of the variety of approaches to process diagnosis and fault-tolerant control. The authors have extensive teaching experience with graduate and PhD students, as well as with industrial experts. Parts of this book have been used in courses for this audience. The authors give a comprehensive introduction to the main ideas of diagnosis and fault-tolerant control and present some of their most recent research achievements obtained together with their research groups in a close cooperatio n with European research projects. The third edition resulted from a major re-structuring and re-writing of the former edition, which has been used for a decade by numerous research groups. New material includes distributed diagnosis of continuous and discrete-event systems, methods for reconfigurability analysis, and extensions of the structural methods towards fault-tolerant control. The bibliographical notes at the end of all chapters have been up-dated. The chapters end with exercises to be used in lectures.

A geometric approach to fault detection and isolation for bilinear systems

In this paper, a geometric approach to the synthesis of a residual generator for fault detection and isolation (FDI) in bilinear systems is considered. A necessary and sufficient condition to solve the so-called fundamental problem of residual generation is obtained. The proposed approach resorts to extensions of the notions of (C, A)-invariant and unobservability subspaces, and it yields a constructive design method.

Explicit solution to the singular LQ regulation problem

An explicit solution to the multivariable discrete linear quadratic (LQ) regulation problem is obtained in the limiting singular case where the input weighting matrix tends to zero. Such a solution follows from a suitable spectral factorization of the input spectrum density matrix under the assumption that the system is stabilizable and detectable and that its transfer function matrix is of full rank. The suitable spectral factor is shown to be the product of the systems minimum-phase image and its unitary interactor matrix. The unitary interactor matrix defined is a special case of the nilpotent interactor matrix defined by M.W. Rogozinski et al. (1987). >

Adaptive generalized predictive controller for MIMO systems

The multivariate generalized predictive controller (GPC) is studied (Clarke 1987a, Shah 1987). The multivariable GPC algorithm is presented in a stochastic framework, and a model-following capability is introduced in the control law. The method is described for a controlled autoregressive integrated moving average (CARIMA) model, and for the equivalent state-space representation in its innovation form. The closed-loop system equations are derived and analyzed, using the state-space approach.