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 feature...
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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.
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 ...
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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.
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 ...
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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 used for the detection of tool wear and tool breakage in the drilling process.< >
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 t...
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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.
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 t...
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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.
The integration of microelectronics within the actuator allows to not only replace the analog position controller but to add several functions which give the actuator more intelligent functions. The actuator control i...
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The integration of microelectronics within the actuator allows to not only replace the analog position controller but to add 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. 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. The 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.
In modern manufacturing systems it is very important to increase the safety, reliability and availability of the involved components, e.g. industrial robots. Downtime of the entire production line as a result of a sin...
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In modern manufacturing systems it is very important to increase the safety, reliability and availability of the involved components, e.g. industrial robots. Downtime of the entire production line as a result of a single component breakdown will cause high costs which have to be avoided. Hence automaticcontrolled systems of high complexity should be supervised by automatic means and supplemented by appropriate diagnosis methods. Continuous time model-based procedures have been proven to present powerful tools for this purpose. In the present contribution specific approaches of parameter estimation and state estimation are applied to the mechanical components of an industrial robot. Several changes which represent typical mechanical faults were established artificially to the robot. Finally the different approaches are compared.
作者：
T. ReißInstitute of Automatic Control
Laboratory of Control Systems and Process Automation Technical University Darmstadt Landgraf-Georg-Str. 4 D-6100 Darmstadt Germany
The supervision of manufacturing processes is of primary interest in the course of progressive automation. This paper paper presents a new approach in fault diagnosis and supervision of the drilling process. The super...
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The supervision of manufacturing processes is of primary interest in the course of progressive automation. This paper paper presents a new approach in fault diagnosis and supervision of the drilling process. The supervision of manufacturing processes with additional sensors is mostly expensive or not possible at all. Therefore mathematical process models were developed for the drilling process. By means of least squares estimation techniques the physical parameters are determined based on easily measurable signals of the drives. Changes of those process parameters during operation are used for fault diagnosis. Experimental results on two flexible machining centers show the detected parameter changes during operation in dependence on tool wear.
作者：
D. NeumannTechnical University of Darmstadt
Institute of Automatic Control Laboratory of Control Systems and Process Automation Landgraf-Georg-Str. 4 D-6100 Darmstadt Germany
In this paper a method for the signal model based estimation of frequency spectra from sampled signals is presented. The algorithm uses discrete, parametric signal models in z-space, whose parameters are determined by...
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In this paper a method for the signal model based estimation of frequency spectra from sampled signals is presented. The algorithm uses discrete, parametric signal models in z-space, whose parameters are determined by a two step identification algorithm. From these parameters significant oscillations, described by their frequency and concatenated amplitude, are calculated to develop a method for the supervision and fault diagnosis of dynamic systems. The shown results and conclusions are taken from practical tests at machine-tools.
作者：
P. WankeT. ReißInstitut of Automatic Control
Laboratory of Control Systems and Process Automation Technical University Darmstadt Landgraf-Georg-Str. 4 D-6100 Darmstadt Germany
The early detection and localization of faults in machines and drives is of primary interest to make further improvement of the reliability and saftey. This paper presents a new approach in fault diagnosis and supervi...
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The early detection and localization of faults in machines and drives is of primary interest to make further improvement of the reliability and saftey. This paper presents a new approach in fault diagnosis and supervision of main and feed drives with elastic components. The supervision of drives with additional sensors for temperature, pressures or vibrations is usually expensive. Currently, internal process faults are only detected partially and at a rather late stage, by generating alarms if certain limits of the measured signals are exceeded or limit switches stop the machine tool. A process model based approach for fault diagnosis was developed. Dynamic models of each drive are tried and together with easily measurable signals of the drive, like current and speed, physical parameters are estimated. Changes of those process parameters are the symptoms for a diag-nostic inference mechanism. Experimental results with least squares parameter estimation in the form of disrete square root filters are shown.
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