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DESIGN OF A FUZZY-LOGIC BASED DIAGNOSTIC MODEL FOR TECHNICAL processES

FUZZY SETS AND SYSTEMS 1993年第3期58卷 249-271页

作者： ULIERU, M ISERMANN, R Technical University of Darmstadt Institute of Automatic Control Laboratory of Control Engineering and Process Automation Darmstadt Germany

The design and implementation of the heuristic knowledge base for a fuzzy logic-based technical diagnostic problem solving strategy integrated as a heuristic level within a computer assisted fault diagnosis system is considered. Based on knowledge acquisition via expert knowledge (linguistically expressed as fuzzy conditional statements);simulation-based observations of the diagnosed process (as a feature extraction technique for technical diagnostic relevant information);process history and fault statistics, a fuzzy diagnostic model is developed as a fuzzy symptoms-faults mapping and implemented within the heuristic knowledge base. Diagnostic reasoning by MATCHING the proposed fuzzy diagnostic model with the current values of the symptoms (either analytically generated or subjectively observed by the operator) is presented as well as the validation of the design method. first by illustrating it on a very simple simulated process (a low-pass filter) and then by applying it to a simulated DC motor.

关键词： FAULT DETECTION AND DIAGNOSIS POSSIBILITY THEORY LINGUISTIC MODELING KNOWLEDGE ACQUISITION FUZZY NUMBERS APPROXIMATE REASONING EXPERT SYSTEMS

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FAULT-DIAGNOSIS OF MACHINES VIA PARAMETER-ESTIMATION AND KNOWLEDGE processING - TUTORIAL PAPER

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AUTOMATICA 1993年第4期29卷 815-835页

作者： ISERMANN, R [a]Technical University of Darmstadt Institute of Automatic Control Laboratory of Control Engineering and Process Automation Landgraf Georg Str. 4 D-6100 Darmstadt Germany

For further improvement of the reliability and safety of machines the automatic early detection and localization of faults is of high interest. The conventional approach is to monitor some important variables like temperature, pressure, vibration and to generate alarms if certain limits are exceeded. However, developing internal faults are in this way only detected at a rather late stage. By applying static and dynamic process models and common process input and output measurements the inherent relationships and redundancies can be used to detect faults earlier and to localize them better. Changes in process and signal parameters are very well suited for fault detection. The paper describes a general methodology for machines and other processes by using few measurements, dynamic process and signal models and parameter estimation to generate analytical symptoms. Heuristic symptoms observed by the operator or based on, e.g. the process history are another source for fault diagnosis. Both kinds of symptoms are weighted by confidence measures and are fed into a knowledge based fault diagnosis procedure. The diagnosis is performed by forward and backward chaining according to causal fault-symptom trees. The considered machines consist of a motor, a drive chain and a working process or load. They may be electrical motor or combustion engine driven pumps, fans or machine tools with gear or belt drive chains. As one example, experimental results are shown for a DC motor powered feed drive of a machine tool. A summary of practical results with other machines is also given.

关键词： FAULT DETECTION SUPERVISION MONITORING SAFETY PARAMETER ESTIMATION KNOWLEDGE BASE DIAGNOSTICS FAULT TREES INFERENCE MECHANISM, FORWARD AND BACKWARD CHAINING, FEED DRIVE MACHINES

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INTELLIGENT ACTUATORS - WAYS TO AUTONOMOUS ACTUATING SYSTEMS

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AUTOMATICA 1993年第5期29卷 1315-1331页

作者： ISERMANN, R RAAB, U [a]Technical University of Darmstadt Institute of Automatic Control Laboratory for Control Engineering and Process Automation Landgraf Georg Str.4 D-64283 Darmstadt Germany

The integration of microelectronics within the actuator allows not only replacement of the analog position controller but addition of several functions which give the actuator more intelligent functions. The actuator control is performed in different levels and includes adaptive nonlinear control, optimization of speed and precision, supervision and fault diagnosis. The actuator knowledge base comprises actuator models based on parameter estimation, controller design and a storage of the learned behavior. An inference mechanism makes decisions for control and fault diagnosis, and a communication module operates internally and externally. After a short review of important actuator principles and their properties, as examples, electromagnetic and pneumatic actuators are considered and it is shown how the control can be improved considerably by model-based nonlinear control, taking into account time varying nonlinear characteristics and hysteresis effects. Supervision with fault detection indicates faults in the electrical and mechanical subsystems of the actuator. Several experimental results are shown including the implementation on a low-cost microcontroller.

关键词： ACTUATORS INTELLIGENT control FUNCTIONS NONLINEAR ADAPTIVE control SUPERVISION FAULT DIAGNOSIS

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From fault trees to fuzzy relations in managing heuristics for technical diagnosis

From fault trees to fuzzy relations in managing heuristics f...

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IEEE International Conference on Systems, Man and Cybernetics

作者： M. Ulieru Laboratory of Control Engineering and Process Automation Technical University of Darmstadt Darmstadt Germany

A generic possibilistic framework for embracing through fuzzy relations the causal-abductive duality co-existent within the diagnostic information is proposed. As a challenge of the classical fault tree analysis, the proposed approach overpasses the main limitations of the restrictive framework of reliability theory by processing linguistic expert knowledge through the deterministic trees. On a very simple example it is illustrated on how fuzzy relations represent an excellent tool for unified integration of heuristic diagnostic information, as a basis for managing complex diagnostic situations via approximate reasoning.< >

关键词： Fault trees Fault diagnosis Reliability theory Artificial intelligence Cause effect analysis Equations Tree data structures Connectors Uncertainty

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Integrated fault detection and diagnosis

Integrated fault detection and diagnosis

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IEEE International Conference on Systems, Man and Cybernetics

作者： R. Isermann M. Ulieru Institute of Automatic Control Laboratory for Control Engineering and Process Automation Technical University of Darmstadt Darmstadt Germany

The development of technical diagnostic systems has shown that the time has come to bridge the gap between the process-oriented engineering approach and the reasoning-oriented approach. As a contribution to this on-going task, the paper proposes a unified frame for integration of different fault detection and decision techniques via approximate reasoning on analytical and heuristic fuzzy symptoms.< >

关键词： Fault detection Fault diagnosis Artificial intelligence Medical diagnostic imaging Reliability engineering Power engineering and energy Safety Chemical analysis Monitoring Anthropometry

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On the Applicability of Model Based Fault Detection for Technical processes

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IFAC Proceedings Volumes 1993年第2期26卷 551-556页

作者： R. Isermann Laboratory for Control Engineering and Process Automation Institute of Automatic Control Technic unniversity Darmstadt Landgraf-Georg-Straβ 4 D-6100 Darmstadt Germany

Beginning with classical supervision a summary is given on the main principles of model based fault detection methods. Their basic assumptions, results from simulation and experiments allow a discussion of the features of the methods with regard to their applicability. The importance of realistic fault modeling is outlined. Finally the role of model based fault detection as one information source for fault diagnosis is discussed. Several methods of fault detection have to be integrated to perform a powerful diagnosis.

关键词： Fault detection supervision monitoring parameter estimation state estimation parity equations technical processes actuators sensors fault diagnosis

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Detection of Parameter Variations by Continuous-Time Parity Equations

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IFAC Proceedings Volumes 1993年第2期26卷 513-518页

作者： T. Höfling Laboratory of Control Engineering and Process Automation Instite of Automatic Control Technical University of Darmstadt Landgraf-Georg-Str. 4 D-6100 Darmstadt Germany

As many faults induce parameter variations, it is important for detection and diagnosis to observe their timely development. One possibility is to estimate the parameters directly by well-known least squares methods for dynamic systems, but this requires some computational effort at each sampling step. The proposed method uses the easy to calculate parity space equations with special, parameter-sensitive features and state variable filters to generate signal derivatives. Different to previous approaches here parity equations are used in the continuous time domain. Then the connection between physical and model parameters is direct and eases a fault diagnosis. A parameter classification table can be derived from the according pattern of the obtained set of residuals. This table enables to localize which physical parameter has been affected. Furthermore well known parity space design methods can be included for the detection of sensor faults.

关键词： Model-based fault detection parity space continuous-time component faults d.c. motors

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Robust Adaptive control of a Time Varying process Using Parallel Recursive Estimators

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IFAC Proceedings Volumes 1993年第2期26卷 113-116页

作者： O. Hecker T. Knapp R. Isermann Laboratory for Control Engineering and Process Automation Institute for Automatic Control Technical University Darmstadt Landgraf-Georg-Straβe 4 D-64283 Dannstadt Germany

A parameter-adaptive controller to control the simulated plant of the "1993 IFAC World Congress Bench Mark Design Example" is presented. To cope with the rather fast time-varying process parameters a set of parallel estimators is used. Due to a cyclic restart procedure each of these estimators is working with another time window. For the controller itself an algorithm is used that realizes a controller with variable robustness. Simulation results are presented.

关键词： Adaptive control time-varying systems recursive estimation supervision variable robustness

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Model based detection of tool wear and breakage for machine tools

Model based detection of tool wear and breakage for machine ...

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IEEE International Conference on Systems, Man and Cybernetics

作者： R. Isermann M. Ayoubi H. Konrad T. Reiss Inst. of Autom. Control Tech. Hochschule Darmstadt Germany Institute of Automatic Control Laboratory of Control Engineering and Process Automation Technical University of Darmstadt Darmstadt Germany

This approach describes a methodology for the fault detection in machine tools by using few robust sensors and dynamic process models. Two different model based methods, parameter estimation and state estimation, are ... 详细信息

关键词： Machine tools Fault detection Feeds Drilling Signal processing automation Robust control Parameter estimation State estimation Mechanical variables control

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Examples for fault detection in closed loops

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Annual Review in Automatic Programming 1992年 17卷 235-240页

作者： R. Deibert R. Isermann Institute of Automatic Control Laboratory of Control Engineering and Process Automation Technical University Darmstadt Landgraf-Georg-Str. 4 D-6100 Darmstadt Germany

Fault diagnosis of closed control loops and its components is a topic which requires deeper investigation. Main problems are the different targets of control and fault diagnosis. control loops are designed to reduce the influence of deviations of controller, actuator, the process itself and the sensors with regard to the desired input/output behaviour. On the other hand, the aim of fault diagnosis procedures is to detect these deviations in order to decide whether they cause a failure, damage or not allowed process behaviour, and to arrange appropriate actions. State space approaches are first investigated for fault detection in control loops because they need not necessarily excitation, a cirumstance which is given in many control loops. As a first stage of the current investigations, control loops with linear components will be examined.

关键词： control loop model-based state estimation parameter estimation

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