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Influences of Braking System Faults on the Vehicle Dynamics

IFAC Proceedings Volumes 2001年第1期34卷 113-118页

作者： Harald Straky Michael Kochem Jürgen Schmitt Rainer Hild Rolf Isermann Institute of Automatic Control Laboratory of Control Engineering and Process Automation Darmstadt University of Technology Landgraf-Georg-Str. 4 D-64283 Darmstadt. Germany Phone: +496151 16-7412. FAX: +496151 16-7421

From a safety point of view the braking system is, besides the driver, one of the key subsystems in a car. The driver, as an adaptive control system, might not notice small faults in the hydraulic part of the braking system and sooner or later critical braking situations, e.g. due to a brake-circuit failure, may occur. Most of the drivers are not capable to deal with such critical situations. Therefore this paper investigates the influence of faults in the braking system on the dynamic vehicle behavior and the steering inputs of the driver to keep the vehicle on the desired course.

关键词： vehicle dynamics hydraulics brakes failure

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Nonlinear Identification and Adaptive control of Combustion Engines

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IFAC Proceedings Volumes 2001年第14期34卷 1-12页

作者： Rolf Isermann Norbert Müller Darmstadt University of Technology Institute of Automatic Control Laboratory of Control Systems and Process Automation Landgraf-Georg-Str. 4 D-64283 Darmstadt Germany Tel: +49/6151-162114 Fax: +49/6151-293445

Advanced engine control systems require accurate models of the thermodynamic-mechanical process, which are substantially nonlinear and often time-variant. After briefly introducing the identification of nonlinear processes with grid-based look-up tables and a special local linear Radial Basis Function network (LOLIMOT), a comparison is made with regard to computation effort, storage requirements and convergence speed. A new training algorithm for online adaptation of look-up tables is introduced which reduces the convergence time considerably. Application examples and experimental results are shown for a multidimensional nonlinear model of NOx emissions of a Diesel engine, and for the adaptive feedforward control of the ignition angle of a SI engine.

关键词： Engine control Learning systems Identification Neural networks Feedforward control

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Nonlinear internal model control based on local linear neural networks

Nonlinear internal model control based on local linear neura...

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IEEE International Conference on Systems, Man and Cybernetics

作者： A. Fink O. Nelles Institute of Automatic Control Laboratory of Control Systems and Process Automation Darmstadt University of Technology Darmstadt Germany AT PT DTS FDC Siemens VDO Automotive AG Regensburg Germany

The internal model control (IMC) scheme has been widely applied in the field of process control. This is due to its simple and straightforward controller design procedure as well as its good disturbance rejection capabilities and robustness properties. So far, IMC has been mainly applied to linear processes. This paper discusses the extension of the IMC scheme to nonlinear processes based on local linear models where the properties of the linear design procedures can be exploited directly. The resulting controllers are comparable to gain-scheduled PI or PID controllers which are the standard controllers in process industry. In practice, the tuning of conventional PI or PID controllers can be very time-consuming. In this paper, the design effort of the nonlinear IMC and conventional controller design methods are discussed and the control results are compared by applying it to a Hammerstein process and nonlinear temperature control of a heat exchanger.

关键词： Neural networks automatic control process control Temperature control Electronic mail Three-term control process design Low pass filters Laboratories control system synthesis

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On-Line Fault Detection of Inverter-Fed Induction Motors Using Advanced Signal processing Techniques

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IFAC Proceedings Volumes 2000年第11期33卷 1119-1124页

作者： Armin Wolfram Rolf Isermann Darmstadt University of Technology Institute of Automatic Control Laboratory for Control Engineering and Process Automation Landgraf-Georg-Strasse 4 D-64283 (Germany) Phone: (+49) 6151 167406 Fax: (+49) 6151 293604

Due to the increasing demands concerning reliability, safety and economy of technical processes, on-line fault detection of induction motors is an important topic in the engineering field. Approaches, based on the spectral analysis of motor currents have been frequently proposed. The main drawback of these approaches has been the restriction on induction machines fed by power supplies with constant frequency. Due to the progress in semiconductor technology and power electronics, inverter-fed induction motors providing a wide speed range are more and more employed. This paper proposes the basics of a nonlinear time-domain transformation which is capable of applying the same spectral analysis scheme for different speeds. Finally, experiments are shown for the detection of insulation failures in the stator windings.

关键词： Induction Motor Inverter Fault Detection Time Warping Signal Analysis Stator Currents Insulation Failure Field-Oriented control

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A Smart Actuator with Model-Based FDI Implemented on a Microcontroller

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IFAC Proceedings Volumes 2000年第26期33卷 995-1000页

作者： Olaf Moseler Markus Müller Darmstadt University of Technology Institute of Automatic Control Laboratory of Control Engineering and Process Automation Landgraf-Georg-Strasse 4 D-64283 Darmstadt Germany Phone: +49 - 6151- 167404 Fax: +49 - 6151 - 293604

The device under consideration drives a cabin pressure control valve of modern passenger aircrafts. It is already provided by a wide range of built-in tests. However, these tests do not allow a deep diagnosis of the actuator. Therefore in this paper a model-based approach for detecting and isolating faults is presented. Parameter estimation and parity equations are used for feature generation. The features are compared to that one of the fault-free case. Deviations are fed into a fuzzy rule base in order to isolate the faults. The whole approach is implemented on a 16 bit microcontroller. Experimental results are given.

关键词： Model-Based Fault Detection Fuzzy-Logic Brushless DC Motor Microcontroller

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Fault Detection of a Solenoid Valve for Hydraulic Systems in Vehicles

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IFAC Proceedings Volumes 2000年第11期33卷 119-124页

作者： Olaf Moseler Harald Straky Darmstadt University of Technology Institute of Automatic Control Laboratory of Control Engineering and Process Automation Landgraf-Georg-Strasse 4 D-64283 Darmstadt Germany Phone: +49 - 6151 - 167404 Fax: +49 - 6151 - 293604

In passenger and utility vehicles proportional solenoid valves are used in different hydraulic systems. The valves often have an important impact on the operation quality of succeeding components. However, the correct functioning of the devices is only insufficiently checked. Therefore a novel, model-based approach is going to be presented which is able to estimate the solenoid’s armature stroke based on measured voltage und current. No expensive position sensor is required, that could reduce the overall reliability. Evaluating the reconstructed stroke, faults such as blockade, increased friction, etc. can be detected. But also faults in the electrical part of the valve may be isolated. Instead of replacing whole components in case of a faulty behaviour, the self check of the solenoid valve itself can assist in judging whether the component or the solenoid is faulty. Hence, maintenance costs can be optimized. The paper includes experimental results. Aspects of the microcontroller implementation are addressed.

关键词： Fault Detection Solenoid Hydraulic Valve Microcontroller

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FIT - Filtering and Identification Tool

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IFAC Proceedings Volumes 2000年第15期33卷 863-868页

作者： Olaf Moseler Michael Vogt Darmstadt University of Technology Institute of Automatic Control Laboratory of Control Engineering and Process Automation Landgraf-Georg-Strasse 4 D-64283 Darmstadt Germany Phone: +49 - 6151 - 167404 Fax: +49 - 6151 - 293604

The program "Filtering and Identification Tool" designed for MATLAB provides an easy to handle tool for linear system identification of continuous time domain systems. But also discrete time models may be identified. The only property the process model must fulfill is that it has to be linear in the parameters. A graphical user interface guides the research engineer through all steps. As most of the time consuming algorithms are implemented as C-functions, the identification even with a huge amount of data takes only few seconds. To identify continuous time process models, derivatives of the input and output signals are required. However, these signals often cannot be measured. Therefore digital filters such as state variable filter (SVF) and differentiating finite impulse response (FIR) filters are integrated into FIT to provide the necessary derivatives. For the identification task various recursive parameter estimation methods like recursive least means squares (RLS), discrete square root filter in information form (DSFI), normalized least means squares (NLMS), etc. are included, too. Recursive algorithms with exponential fading memory (variable step size in case of NLMS) were chosen in order to identify time variant systems. But also for the offline design of real-time fault detection or adaptive control schemes using parameter estimation methods a variable forgetting factor is important to be able to track varying parameters. Thus, the main advantage of the Filtering and Identification Tool in comparison to existing software tools for system identification is the integration of both parameter estimation methods and differentiating filters.

关键词： system identification differentiating filters continuous time models

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Design and Application of Digital FIR Differentiators Using Modulating Functions

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IFAC Proceedings Volumes 2000年第15期33卷 1037-1042页

作者： Armin Wolfram Olaf Moseler Darmstadt University of Technology Institute of Automatic Control Laboratory for Control Engineering and Process Automation Landgraf-Georg-Strasse 4 D-64283 Darmstadt (Germany) Phone: (+49) 6151 167406 Fax: (+49) 6151 293604

Continuous process Models are widely used in system identification and fault detection. However, dynamic models require the derivatives of the process' input and output signals. Often they cannot be accessed by measurements. Thus they have to be provided by digital filters. Commonly state variable filters are used for this purpose. But this approach has a couple of drawbacks caused by the recursive structure of the filter. In this paper a consistent approach for the design of FIR differentiators by means of modulating functions is proposed. Finally the application of these filters for fault detection using a microcontroller is presented.

关键词： Finite Impulse Response Filter Differentiators Modulating Functions System Identification Fault Detection

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Model Based Fault Detection of Vehicle Suspension and Hydraulic Brake Systems

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IFAC Proceedings Volumes 2000年第26期33卷 1073-1078页

作者： Marcus Börner Harald Straky Thomas Weispfenning Rolf Isermann Institute of Automatic Control Laboratory of Control Engineering and Process Automation Darmstadt University of Technology Landgraf-Georg-Str. 4 D-64283 Darmstadt Germany Phone: +49 6151 16-7412 FAX: +49 6151 16-7421

In modern vehicles, mechatronic systems are increasingly used. To improve reliability, safety and economy, an early recognition of small or drifting faults is becoming increasingly important. After a short introduction to methods of model based fault detection and diagnosis, application examples for fault detection of automotive vehicle suspension and hydraulic brake systems are given.

关键词： fault detection parameter estimation parity equation vehicle suspension tire pressure solenoid ABS-valve hydraulic brake system

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H ∞ Parameter Identification for Inflight Detection of Aircraft Icing: The Time-Varying Case

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IFAC Proceedings Volumes 2000年第15期33卷 289-294页

作者： James W. Melody Thomas Hillbrand Tamer Başar William R. Perkins Coordinated Science Laboratory University of Ilinois 1308 West Main Street Urbana IL 61801-2307/ USA Darmstadt University of Technology Institute of Automatic Control Laboratory of Control Systems and Process Automation Landgraf-Georg-Strasse 4 D-64283 Darmstadt Germany

Inflight parameter identification of aircraft flight dynamics is considered in this paper in the context of an ice management system. In particular, an H ∞ parameter identification algorithm is evaluated in terms of detecting an aircraft icing event when only a noisy state measurement is available. While previous studies have addressed identification during a pilot-induced maneuver, taking advantage of the excitation due to input, this paper addresses identification during cruise, where excitation is provided only by unknown disturbances due to turbulence. Simulation results show that for moderate turbulence levels, the H ∞ algorithm provides a timely and unambiguous icing indication.

关键词： Aircraft control H ∞ Identification Time-Varying Systems Robustness

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