Parity relations are rearranged forms of the direct input-output model equations. In the presence of faults, they return nonzero residuals. With an appropriate transformation, these residuals may be 'structured...
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Parity relations are rearranged forms of the direct input-output model equations. In the presence of faults, they return nonzero residuals. With an appropriate transformation, these residuals may be 'structured' to facilitate fault isolation. In this paper, we describe an alternative to algebraic transformation to obtain such residuals. First the Boolean structure of the residual-set is determined, then the models underlying each of the residual-structures are determined by direct system identification. This technique may be applied to nonlinear models of any complexity. As an extension of this approach, the models for all possible residual structures are first determined and then the optimal residual set is selected in a structurally constrained local optimization procedure. The technique is demonstrated on a two-input four-output polynomial nonlinear system.
Importance of physical modeling, called also 'virtual prototyping', grows with the increasing power of computers as well as with the growing demands on control-system dynamics. The paper advocates for the mult...
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Importance of physical modeling, called also 'virtual prototyping', grows with the increasing power of computers as well as with the growing demands on control-system dynamics. The paper advocates for the multipole approach to physical modeling in contrast to the well-known bond-graph approach. As the topological representation of multipole models is isomorphic with the geometrical representation of the modeled real systems, these models can be easily set up based on mere inspection of the systems. The relationship between multipole and bond-graph approaches is explained using linear graphs. A definition of multiports as a mapping of the subsystem energetic interactions from the geometric onto the topological space is introduced. It is shown that it is the oversimplified representation of multiports what makes the bond graphs cumbersome and ambiguous.
Cascade compensators are often used to direct the available control energy to a particular subset of plant modes whose dynamics is to be modified. In certain applications the cascade compensators can be taken to be si...
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Cascade compensators are often used to direct the available control energy to a particular subset of plant modes whose dynamics is to be modified. In certain applications the cascade compensators can be taken to be simple frequency selective filters such as low-pass or band-pass filters. There are applications in which such simple solutions do not work. This paper describes a method to obtain cascade compensators when frequency selective filters do not suffice. The computations required to implement the results are rather simple and involve the calculation of the generalized singular value decomposition of a matrix pair constructed with frequency response data. When combined with robust methods for controller design, the results in this paper yield a simple and effective method for designing controllers that modify the dynamics associated with a specified subset of plant poles.
A state-of-the-art transient dynamometer engine test system has been developed in the Powertrain control Research Laboratory (PCRL) at the University of Wisconsin-Madison. This system includes a hydrostatic dynamomete...
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A state-of-the-art transient dynamometer engine test system has been developed in the Powertrain control Research Laboratory (PCRL) at the University of Wisconsin-Madison. This system includes a hydrostatic dynamometer capable of excitation in excess of 300Hz, integrated with a controller running the dynamic driveline equations in real time to calculate the instantaneous engine loads during transients. This hardware-in-the-loop (HIL) virtual engine loading system can be a powerful tool for use in engine and powertrain research, as well as control and diagnostic algorithm development and validation. This paper describes the system and presents experimental open loop and closed loop HIL data from the transient dynamometer system that represents the virtual vehicle.
There is a growing trend to use object-based implementations and modeling in industrial control applications. However, the object-based approach imposes new theoretical and practical problems. Those problems are due t...
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There is a growing trend to use object-based implementations and modeling in industrial control applications. However, the object-based approach imposes new theoretical and practical problems. Those problems are due to a higher abstraction level that is achievable with objects as compared to the more traditional, state-based fault detection and isolation methods (FDI) approaches. This paper presents a description of the problems and solutions to them in the framework of a discrete FDI method referred to as ontological control. The results are also relevant in respect to domain-independent failure recovery methods, such as [8].
The analysis of aircraft handling qualities using numerical criteria is an important aspect during the development of modern aircraft. For this purpose and for the validation of new criteria DLR Institute of Flight Me...
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The analysis of aircraft handling qualities using numerical criteria is an important aspect during the development of modern aircraft. For this purpose and for the validation of new criteria DLR Institute of Flight Mechanics has developed a software tool which contains the most important handling qualities criteria and databases. The package is based on MATLAB, a widely used numeric computation and visualization software. HAREM features a central interface for an easy access to all criteria and databases, the possibility to evaluate several configurations with a single command as well as a convenient presentation and handling of the results. This paper contains a description of the concept and the application spectrum of HAREM as well as a short demonstration.
This paper presents the new toolbox 'MIRCOS' (MIcrocontroller-based Real time controlsystem) for graphical programming and real time operation of the standard 16-bit microcontroller 80C166 ([13]) using Matlab...
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This paper presents the new toolbox 'MIRCOS' (MIcrocontroller-based Real time controlsystem) for graphical programming and real time operation of the standard 16-bit microcontroller 80C166 ([13]) using Matlab and Simulink. With the toolbox presented here, Rapid control Prototyping is possible on this widely available hardware. The system can also be used for Hardware-in-the-Loop Simulations. The complete controller synthesis, the automatic generation and implementation of the control program on the microcontroller, and the control task itself can be carried out under Matlab's comfortable user interface. Furthermore, the full functionality of Matlab and Simulink can be used in MIRCOS, for instance for parameter hand-off or visualization without interrupting or impeding the control task running on the 80C166.
The paper presents the design considerations and implementational aspects of the Adaptive Blockset for Simulink which has been developed in a prototype implementation. The basics of indirect adaptive controllers are s...
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The paper presents the design considerations and implementational aspects of the Adaptive Blockset for Simulink which has been developed in a prototype implementation. The basics of indirect adaptive controllers are summarized. The concept behind the Adaptive Blockset for Simulink is to bridge the gap between simulation and prototype controller implementation. This is done using the code generation capabilities of Real Time Workshop in combination with C s-function blocks for adaptive control in Simulink. In the paper the design of each group of blocks normally fund in adaptive controllers is outlined. The block types are, identification, controller design, controller and state variable filter. The use of the Adaptive Blockset is demonstrated using a simple laboratory setup. Both the use of the blockset for simulation and for rapid prototyping of a real-time controller are shown.
This paper presents the modeling environment VERDICT which intends to make the method of formal verification applicable to logic controlled chemical plants. The tool offers textual and graphical editors to set up mode...
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This paper presents the modeling environment VERDICT which intends to make the method of formal verification applicable to logic controlled chemical plants. The tool offers textual and graphical editors to set up models of plant and controller. The plant model can be specified as hybrid dynamical or (timed) discrete systems, which are then translated automatically into models that are verifiable with existing model-checking tools. Furthermore, VERDICT allows to include the controller model by specifying it in IL code directly. The contribution illustrates the different features of the framework, the underlying modeling paradigm, and some aspects of the analysis using a simple technical example.
The problem of change detection in signals using linear regression models is addressed. The most algorithms presented make use of two AR models: the first one is a reference model and the second one is a current model...
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The problem of change detection in signals using linear regression models is addressed. The most algorithms presented make use of two AR models: the first one is a reference model and the second one is a current model updated via a sliding block. Changes are detected when a suitable distance between these two models is high. Three distance measures are considered in the paper: cepstral distance, log-likelihood ratio (justified by GLR) and a distance involving the cross-entropy of the two conditional probabilities laws (divergence test). Finally, a change detection algorithm using three models and the evolution of Akaike Information Criterion is presented. Some results on the application of the discussed algorithms in seismic signal segmentation are included.
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