For many practical applications, a combination of theoretical and experimental modelling appears feasible. Qualitative knowledge about the most significant effects are often known or easily accessible. This contributi...
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For many practical applications, a combination of theoretical and experimental modelling appears feasible. Qualitative knowledge about the most significant effects are often known or easily accessible. This contribution suggests a semi-physical modelling approach based on the special architecture of local models. Due to their inherent transparency, these models are very well suited for the incorporation of mainly qualitative process knowledge. The integration of prior knowledge is realised by an adaptation of the model structure to that one of the process. As a result, the final process-specific models are characterised by high generalisation performance also in situations with only few measurement data.
A design method for determining control sequences for rest-to-rest maneuvers of flexible structures with multiple actuators and multiple resonant modes is described. The problem formulation. is based on a pole cancell...
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A design method for determining control sequences for rest-to-rest maneuvers of flexible structures with multiple actuators and multiple resonant modes is described. The problem formulation. is based on a pole cancellation approach with constraints on both the magnitude and the time rate of change of the control inputs. Time-optimality can be traded for an increased level of robustness with respect to modeling errors. Robustification is achieved by placing additional zeros of the controller on some or all of the resonant poles of the system.
controller performance assessment is a challenging task in industrial processcontrol. In this work, we review the state of research in controller performance assessment and monitoring, and present some commercial imp...
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controller performance assessment is a challenging task in industrial processcontrol. In this work, we review the state of research in controller performance assessment and monitoring, and present some commercial implementations of the technology in process industries. Challenges related to the controller performance evaluation are outlined for research and applications.
This paper presents the design of a model-based supervision and diagnosis system for hydraulic and future electro-hydraulic passenger car braking systems. A state space model of the braking system has been derived, wh...
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This paper presents the design of a model-based supervision and diagnosis system for hydraulic and future electro-hydraulic passenger car braking systems. A state space model of the braking system has been derived, which allows calculation of the individual wheel brake cylinder pressures as well as the amount of brake fluid consumed due to faults in the braking system. Based on this model, a real-time supervision system has been developed, which allows early detection and diagnosis of leakages and air entrapments in the hydraulic subsystem. This supervision system only requires data of sensors which are already available in modern passenger cars.
This paper is concerned with the statistical analysis of closed loop data for diagnosing the causes of poor control loop performance. Higher Order Statistical (HOS) techniques have been developed over the last two dec...
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This paper is concerned with the statistical analysis of closed loop data for diagnosing the causes of poor control loop performance. Higher Order Statistical (HOS) techniques have been developed over the last two decades, but until now have not been applied to the area of process monitoring. The main contribution of this work is to utilize the higher order statistical tools such as cumulants and their frequency domain counterparts (bispectrum, bicoherence, trispectrum) to detect and quantify the non-Gaussianity and nonlinearity of regulated processes or control error variables which are sometimes the main contributors to the poor performance of many of the control loops. The bicoherence index together with the process and manipulated variable plots are used to diagnose the sources of system nonlinearities. Successful application of the proposed method is demonstrated on simulated as well as industrial data.
This paper presents fuzzy identification of two bioprocesses employing TSK-type models. A “Modified Gram-Schmidt” (MGS) orthogonal estimator is used to estimate the consequent parameters. This approach is then appli...
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This paper presents fuzzy identification of two bioprocesses employing TSK-type models. A “Modified Gram-Schmidt” (MGS) orthogonal estimator is used to estimate the consequent parameters. This approach is then applied to identify two distinct cases involving dissolved oxygen concentration: one related to a bioreactor and the other one related to an activated sludge process. The obtained models are then cross-validated.
The internal model control (IMC) scheme has been widely applied in the field of processcontrol. So far, IMC has been mainly applied to linear processes. This paper discusses the extension of the IMC scheme to nonline...
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The internal model control (IMC) scheme has been widely applied in the field of processcontrol. 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 linear design procedures can be exploited. The IMC scheme results in controllers that 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 whereas the IMC design procedure is very simple and reliable. In this paper, the design effort of the IMC and conventional controller design methods will be discussed and control results will be compared by application to nonlinear control of an industrial-scale heat exchanger.
Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mix...
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Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mixture is explored. An evaluating method is proposed, and the pertinent optimization model is then derived. The ethanol-water system is studied as an illustrative example. The optimization results show that the maximum energy saving in ITCDIC process is about 35% and the maximum operating cost saving in ITCDIC process is about 30%,as compared with a conventional distillation column(CDIC) under the minimum reflux ratio operating; the optimal operating pressure of the rectifying section is found to be around 0.25 MPa; the effects of the feed composition,operating pressure and the heat transfer rate on operation are also found and analyzed. It is revealed that ITCDIC process possesses high energy saving potential and promising economical prospect.
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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