This paper describes an approach of how to estimate the vehicle velocity using additional sensors provided by the brake-by-wire actuators. The advantage of brake-by-wire actuators - such as the electro-hydraulic (EHB)...
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This paper describes an approach of how to estimate the vehicle velocity using additional sensors provided by the brake-by-wire actuators. The advantage of brake-by-wire actuators - such as the electro-hydraulic (EHB) and the electro-mechanical brake (EMB) - is that the caliper pressure or the clamping force, respectively, are known. Wheel speed, vehicle acceleration, and caliper pressure or clamping force, respectively, are used to estimate the vehicle velocity using a fuzzy approach. Besides, the mass of the vehicle and the slope of the road are derived from the sensors provided. Finally, it will be shown by measurement results that the velocity of a research vehicle equipped with brake-by-wire actuators and a new ABS approach can be estimated very precisely even at very high wheel slips and different road conditions.
An accurate estimation of the vehicle velocity is one of the greatest challenges in modern vehicle systems. The velocity is needed for the Antilock Braking System (ABS) and Traction control System (TCS) as well as for...
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Due to the increasing demands concerning reliability, safety and economy of technical processes, the on-line monitoring of induction motors is an important topic in the engineering field. In this paper, a model-based ...
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Due to the increasing demands concerning reliability, safety and economy of technical processes, the on-line monitoring of induction motors is an important topic in the engineering field. In this paper, a model-based ...
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Due to the increasing demands concerning reliability, safety and economy of technical processes, the on-line monitoring of induction motors is an important topic in the engineering field. In this paper, a model-based approach for fault detection and diagnosis of nonlinear processes is employed. The supervision of nonlinear systems is often very difficult in view of the lack of accurate models. However, neuro-fuzzy models may help to cope with this problem, as they can be trained from measured data. In this contribution the application of a multi-model approach for fault detection and diagnosis of induction motors is presented. For this purpose the process is decomposed in several subprocesses.
Fault detection is increasingly an essential part of vehicle development. Integrating such fault detection subsystems raises the reliability, maintainability, and safety of automobile components. Until now, the suspen...
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Fault detection is increasingly an essential part of vehicle development. Integrating such fault detection subsystems raises the reliability, maintainability, and safety of automobile components. Until now, the suspension system was not a safety-critical component, but with the introduction of global chassis control systems this system is getting more important. Therefore, the paper presents fault detection algorithms for the suspension system. Real measurements of a vehicle are made to compare the advantages of the different fault detection algorithms.
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.
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 proc...
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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.
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.
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.
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