Showing papers by "Ron J. Patton published in 2009"

Actuator fault estimation and compensation based on an augmented state observer approach

Abstract: Faults or process failures may drastically change system behaviour leading to performance degradation and instability. The reliability and fault-tolerance of a control system can be achieved through the design of either an active or passive Fault Tolerant Control (FTC) scheme. This paper proposes a new approach to fault compensation for FTC using fault estimation by which the faults acting in a dynamical system are estimated and compensated within an adaptive control scheme with required stability and performance robustness. The FTC scheme has an augmented state observer (ASO) in the control system, which has an intrinsic robustness in terms of the stability and performance of the estimation error. The design concepts are illustrated using the notion that the friction forces in a mechanical system can be estimated and compensated to give good control performance and stability. The example given is that of a non-linear inverted pendulum with Stribeck friction.

An Adaptive Approach to Active Fault-Tolerant Control

Abstract: In this Faults or process failures may drastically change system behaviour leading to performance degradation and instability. The reliability and fault-tolerance of a control system can be achieved through the design of either an ac- tive or passive Fault Tolerant Control (FTC) scheme. This paper proposes a new approach to fault compensation for FTC using fault estimation by which the faults acting in a dynamical system are estimated and compensated within an adaptive control scheme with required stability and performance robustness. The FTC scheme has an augmented state observer (ASO) in the control system, which has an intrinsic robustness in terms of the stability and performance of the estimation error. The design concepts are illustrated using the notion that the friction forces in a mechanical system can be estimated and compensated to give good control performance and stability. The example given is that of a non-linear inverted pen- dulum with Stribeck friction.

A Fault-Tolerant Control approach to friction compensation

Abstract: The control of systems that involve friction presents interesting challenges. Recent research has focused on detailed modeling of friction phenomena in order to use robust on-line friction compensation procedures, attempting to cancel out the friction force effect in the feedback control. The friction modeling problem remains a very difficult challenge. The friction effect acting in a dynamic system can be viewed as an actuator fault with time-varying characteristics to be estimated and compensated within a Fault-Tolerant Control (FTC) scheme, so that the limitations arising from the use of a friction model are obviated. This work is motivated by the combined use of sliding mode estimation and sliding mode control theories providing an effective and robust FTC strategy. The approach is illustrated using a non-linear inverted pendulum with Stribeck friction. Necessary and sufficient conditions for estimation (as a matched uncertainty) and output feedback stability are from [1, 2]. New ideas are two-fold (a) the concept of viewing friction as a fault-effect and (b) the combined use of sliding mode friction estimation and control.

Model-based fault diagnosis approaches with application to an industrial gas turbine simulator

Abstract: In this work, different model-based procedures exploiting the analytical redundancy principle for the detection and isolation of the input-output sensor faults on a gas turbine simulated process are presented and compared. The contribution of the paper consists of exploiting several identification schemes in connection with linear and nonlinear residual generator design procedures for diagnostic purposes. Thus, it will be shown that black-box modelling and output estimation approaches to fault diagnosis are in particular advantageous in terms of solution complexity and performance achieved. The effectiveness and the capabilities of the proposed fault diagnosis strategies are analysed by means of estensive simulation of the industrial gas turbine model, in the presence of measurement and modelling errors.

PLS-based FDI of a Three-Tank laboratory system

Abstract: The problems of fault detection and isolation of dynamic systems has been studied intensively in the recent years and many successful industrial applications have been reported. In the main these studies have been restricted to model based techniques, with few reports of successful implementation of data driven approaches. These data driven approaches have been range from the application of linear regression techniques, to neuro-fuzzy systems. This paper reports on application of, Multivariate Statistical Process Control (MSPC) methodologies, which can provide a diagnostic tool for the on-line or real time monitoring and detection of the process malfunction is proposed. Finally the effectiveness of Partial Least Squares (PLS) in FDI of the Three-Tank system are represented and discussed through simulation results.