Advanced engine controlsystems require accurate models of the thermodynamic-mechanical process, which are substantially nonlinear and often time-variant. After briefly introducing the identification of nonlinear proc...
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Advanced engine controlsystems 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.
The internal model control (IMC) scheme has been widely applied in the field of processcontrol. This is due to its simple and straightforward controller design procedure as well as its good disturbance rejection capa...
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The internal model control (IMC) scheme has been widely applied in the field of processcontrol. 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.
Globalization and growing new markets, as well as increasing emission and fuel consumption requirements force the car manufacturers and their suppliers to develop new engine control strategies in shorter time periods....
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Globalization and growing new markets, as well as increasing emission and fuel consumption requirements force the car manufacturers and their suppliers to develop new engine control strategies in shorter time periods. This can mainly be reached by development tools and an integrated hardware and software environment enabling rapid implementation and testing of advanced engine control algorithms. The structure of a Rapid control Prototyping (RCP) system is explained, which allows fastmeasurement signal evaluation, and rapid prototyping of advanced engine control algorithms. A hardware-in-the-Ioop simulator for Diesel engine control design is illustrated, simulation results for a 40 tons truck are presented. Providing efficient engine models for the proposed development tools, a dynamic local linear neural network approach is explained and appliedfor modelling the NO x emission characteristics of a 1.9 liter direct injection Diesel engine. Furthermore the application of a RCP system is exemplified by the application of combustion pressure based closed-loop ignition timing control for a SI engine. Experimental results are shown for a 1.0 liter SI engine on a dynamic engine test stand.
The detection and diagnosis of faults in technical systems is of great practical significance. With the help of recent data transfer techniques, service technicians must not necessarily be on-site in order to diagnose...
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The detection and diagnosis of faults in technical systems is of great practical significance. With the help of recent data transfer techniques, service technicians must not necessarily be on-site in order to diagnose the cause of failure. Therefore tele-diagnosis can be defined as a service making use of modern communication channels. However, further progress can be achieved by automating the supervision task. An early detection of faults may help to avoid product deterioration, performance degradation, major damage to the machinery itself and damage to human health or even loss of lives. Furthermore, by employing modern diagnostic systems, faults can even be detected before they lead to a partial or total failure of the plant. This information can be utilised to plan maintenance cycles and thus to minimise plant outages. Within this paper a component-based plant monitoring approach is proposed which relies on the idea that the supervision of complex plants can take place in the individual components.
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 ...
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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.
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 ...
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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.
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 spe...
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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.
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 a...
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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.
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...
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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.
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 id...
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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.
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