Browsing by Author "Allgöwer, Frank"

Now showing 1 - 20 of 23

Open Access
30jähriges Jubiläum des Studiengangs Technische Kybernetik : Reden zum Festakt am 23. Juni 2001
(2004) Tilebein, Meike; Allgöwer, Frank; Fritsch, Dieter; Buhlmann, Bettina; Gilles, Ernst-Dieter; Banzhaf, Wolfgang; Sorg, Helmut; Pertschi, Ottmar (Herausgeber)
Inhalt: Tilebein, Meike (Universität Stuttgart, Betriebswirtschaftliches Institut): Vorwort der Vorsitzenden des Vereins Alumni des Studiengangs Technische Kybernetik der Universität Stuttgart e. V. (S. 7 - 8); Festprogramm (S. 9); Allöwer, Frank (Universität Stuttgart, Institut für Systemtheorie technischer Prozesse): Begrüßung (S. 11 - 13); Fritsch, Dieter (Rektor der Universität Stuttgart): Grußwort (S. 15 - 17); Buhlmann, Bettina (Ministerium für Wissenschaft Forschung und Kunst Baden-Württemberg): Grußwort (S. 19 - 21); Gilles, Ernst Dieter (Universität Stuttgart, Institut für Systemdynamik und Regelungstechnik): 30 Jahre Technische Kybernetik (S. 23 - 27); Banzhaf, Wolfgang (Universität Dortmund, Fachbereich Informatik, Lehrstuhl für Systemanalyse): Kybernetik im Jahrhundert der Biologie (S. 29 - 40); Tilebein, Meike: Verleihung des Preises der Kyb-Alumni für besonderes studentisches Engagement (S. 41 - 45); Tilebein, Meike: Verleihung der Ehrenmitgliedschaft der Kyb-Alumni an Prof. Helmut Sorg (S. 47 - 50); Sorg, Helmut (Universität Stuttgart, Institut A für Mechanik, emerit.): Rede zur Verleihung der Ehrenmitgliedschaft der Kyb-Alumni e. V. (S. 51 - 55); Vorführung: Robotics Wettbewerb von Erstsemestern des Studiengangs Technische Kybernetik (S. 57)
Open Access
μ-Suboptimal design of a robustly performing controller for a chemical reactor
(1994) Amann, Notker; Allgöwer, Frank
The design of robustly performing controllers for an important class of control problems is treated. The problem is dealt with in the structured singular value (μ)-framework. The systems considered are characterized by weak nonlinearities and parametric and unstructured uncertainties. Nonlinear effects are taken into account via linearization families. Parametric uncertainty is included in a non-conservative way. Both lead to a μ-synthesis problem with repeated scalar real perturbations. As no direct solution to such a μ-synthesis problem is known to date, an iterative approach comprising both μ-analysis of the actual problem and D-K-iteration for a modified problem is shown. This approach is applied to a realistic continuous stirred-tank reactor for production of cyclopen-tenol to show the applicability to non-trivial MIMO process control problems.
Open Access
Bcl-2-mediated control of TRAIL-induced apoptotic response in the non-small lung cancer cell line NCI-H460 is effective at late caspase processing steps
(2018) Danish, Lubna; Imig, Dirke; Allgöwer, Frank; Scheurich, Peter; Pollak, Nadine
Open Access
Chemical process control : present status and future needs ; the view from European industry
(1991) Schuler, Hans; Allgöwer, Frank; Gilles, Ernst Dieter
Not only in Europe, chemical process control is characterized by a broad invasion of distributed control systems into chemical plants. The information integration from process control up to business management is a great challenge of today which follows from the overall computerization of production. Most of the recent progress in process automation results from the application of computer science paradigms to control systems, and of advanced developments in field instrumentation. Despite these advances and the considerable progress made in process control theory, there is only limited acceptance and application of modern advanced process control methodologies in industrial practice. This paper is an attempt to summarize the European discussion on the reasons for these facts.
Open Access
Chemical process control: a german perspective
(1992) Allgöwer, Frank
This paper focuses on developments in controller design that we think can have a significant impact on the solution of practical process control problems, and try to summarize the discussion in Germany on this subject.
Open Access
Communication networks in control: new dimensions of complexity
(2009) Allgöwer, Frank; Blind, Rainer; Münz, Ulrich; Wieland, Peter
Open Access
Design of robustly performing controllers for a class of practical control problems
(1993) Amann, Notker; Allgöwer, Frank
The design of robustly performing controllers for a class of practical control problems is considered, involving both parametric and unstructured uncertainty. The problem is dealt with in the structured singular value (μ)-framework. An iterative approach comprising both μ-analysis of the detailed problem and D-K-iteration for a modified problem is proposed, as no direct solution to the detailed μ-synthesis problem is known to date. With a practical MIMO process control example it is shown that this approach leads to controllers that exhibit robust performance.
Open Access
A distributed solution to the adjustable robust economic dispatch problem
(2013) Lorenzen, Matthias; Bürger, Mathias; Notarstefano, Giuseppe; Allgöwer, Frank
The problem of maintaining balance between consumption and production of electric energy in the presence of a high share of intermittent power sources in a transmission grid is addressed. A distributed, asynchronous optimization algorithm, based on the ideas of cutting-plane approximations and adjustable robust counterparts, is presented to compute economically optimal adjustable dispatch strategies. These strategies guarantee satisfaction of the power balancing constraint as well as of the operational constraints for all possible realizations of the uncertain power generation or demand. The communication and computational effort of the proposed distributed algorithm increases for each computational unit only slowly with the number of participants, making it well suited for large scale networks. A distributed implementation of the algorithm and a numerical study are presented, which show the performance in asynchronous networks and its robustness against packet loss.
Open Access
Dynamische Simulation verfahrenstechnischer Prozesse und Anlagen : ein Vergleich von Werkzeugen
(1994) Watzdorf, Rüdiger von; Allgöwer, Frank; Helget, Andreas; Marquardt, Wolfgang; Gilles, Ernst Dieter
Zusammenfassend zeigen unsere Erfahrungen, daß sich prinzipiell alle betrachteten Werkzeuge zur Simulation verfahrenstechnischer Prozesse und Anlagen eignen. Die Werkzeuge zeichnen sich allerdings durch eine unterschiedliche Zielrichtung aus: SlMULINK bietet einen sehr hohen Modellimplementierungs-, Verschaltungs- und Bedienkomfort; ACSL und SPEEDUP sind für die Modellierung und Implementierung neuer Modelle besonders geeignet, wobei SPEEDUP speziell die Bedürfnisse der Verfahrenstechnik unterstützt; DIVA ist weniger auf den Modellierer und mehr auf den Anwender ausgerichtet, der aus vorhandenen Bibliotheken Modelle auswählt, parametriert und verschaltet.
Open Access
An engineering perspective on nonlinear H∞ control
(1994) Allgöwer, Frank; Rehm, Ansgar; Gilles, Ernst Dieter
The focus is on the question whether meaningful practical control problems for nonlinear systems can be expressed and solved in the nonlinear H∞ framework. Approximate I/O-linearization of a realistic chemical reactor, that cannot be I/O-linearized exactly, is given.
Open Access
H∞-control of differential-algebraic-equation systems
(1998) Rehm, Ansgar; Allgöwer, Frank
In this paper H∞ control of high index and non-regular linear differential-algebraic-equation systems is addressed. Based on a generalization of the bounded real lemma (BRL) to index one systems, all linear output feedback controllers in standard, ie non-descriptor, state space form solving the H∞ control problem can be characterized via biaffine matrix inequalities (BMIs). In a second step a congruence transformation and a subsequent change of variables show that certain linear matrix inequalities (LMIs) necessarily must hold in order to admit a solution of the H∞ control problem. However, these conditions are not sufficient. Necessary and sufficient conditions for the existence of a controller solving the H∞ control problem are derived as BMIs of reduced order compared to the original characterization via the BRL. The approach is illustrated by a simple example.
Open Access
Identification of models of heterogeneous cell populations from population snapshot data
(2011) Hasenauer, Jan; Waldherr, Steffen; Doszczak, Malgorzata; Radde, Nicole; Scheurich, Peter; Allgöwer, Frank
Background: Most of the modeling performed in the area of systems biology aims at achieving a quantitative description of the intracellular pathways within a "typical cell". However, in many biologically important situations even clonal cell populations can show a heterogeneous response. These situations require study of cell-to-cell variability and the development of models for heterogeneous cell populations. Results: In this paper we consider cell populations in which the dynamics of every single cell is captured by a parameter dependent differential equation. Differences among cells are modeled by differences in parameters which are subject to a probability density. A novel Bayesian approach is presented to infer this probability density from population snapshot data, such as flow cytometric analysis, which do not provide single cell time series data. The presented approach can deal with sparse and noisy measurement data. Furthermore, it is appealing from an application point of view as in contrast to other methods the uncertainty of the resulting parameter distribution can directly be assessed. Conclusions: The proposed method is evaluated using artificial experimental data from a model of the tumor necrosis factor signaling network. We demonstrate that the methods are computationally efficient and yield good estimation result even for sparse data sets.
Open Access
Look-ahead cyclic pitch control using LIDAR
(2010) Schlipf, David; Schuler, Simone; Grau, Patrick; Allgöwer, Frank; Kühn, Martin
LIDAR (Light detection and ranging) systems are able to provide preview information of wind disturbances at various distances in front of wind turbines. This information can be used to improve the control of wind turbines. This paper compares a predictive feedforward control structure combined with common PI controllers to a baseline controller and to an H∞ approach showing the advantage of look-ahead control to reduce wind turbine loads. The control design is verified by simulations with a turbulent wind field and a full nonlinear model of the wind turbine.
Open Access
Model Predictive Control for flexible job shop scheduling in Industry 4.0
(2021) Wenzelburger, Philipp; Allgöwer, Frank
In the context of Industry 4.0, flexible manufacturing systems play an important role. They are designed to provide the possibility to adapt the production process by reacting to changes and enabling customer specific products. The versatility of such manufacturing systems, however, also needs to be exploited by advanced control strategies. To this end, we present a novel scheduling scheme that is able to flexibly react to changes in the manufacturing system by means of Model Predictive Control (MPC). To introduce flexibility from the start, the initial scheduling problem, which is very general and covers a variety of special cases, is formulated in a modular way. This modularity is then preserved during an automatic transformation into a Petri Net formulation, which constitutes the basis for the two presented MPC schemes. We prove that both schemes are guaranteed to complete the production problem in closed loop when reasonable assumptions are fulfilled. The advantages of the presented control framework for flexible manufacturing systems are that it covers a wide variety of scheduling problems, that it is able to exploit the available flexibility of the manufacturing system, and that it allows to prove the completion of the production problem.
Open Access
Moment dynamics of Zirconia particle formation for optimizing particle size distribution
(2019) Halter, Wolfgang; Eisele, Rahel; Rothenstein, Dirk; Bill, Joachim; Allgöwer, Frank
Open Access
Multivariable controller design for an industrial distillation column
(1992) Allgöwer, Frank; Raisch, Jörg
In this paper, we report our experience with the design of linear multivariable controllers for a staged binary distillation column with 40 trays. Controller design methods include H∞-minimization, DNA-design, CL-design and H2minimization. Results obtained at the real plant are shown.
Open Access
Nichtlinearer Reglerentwurf auf der Grundlage exakter Linearisierungstechniken
(1993) Allgöwer, Frank; Gilles, Ernst Dieter
Dem nichtlinearen Reglerentwurf mittels exakter Linearisierung liegt eine Zweischritt-Philosophie zugrunde: zuerst wird die nichtlineare Regelstrecke durch eine nichtlineare Rückführung exakt in ein lineares System überführt. Das exakt linearisierte System kann im zweiten Schritt mit linearen Reglerentwurfsverfahren so geregelt werden, daß Stabilität und gutes Regelverhalten erreicht werden. In diesem Übersichtsbeitrag wird eine Einführung und ein Überblick über das Gebiet der exakten Linearisierung gegeben. Anhand von Beispielen werden die Vorteile und Grenzen der Verfahren diskutiert.
Open Access
Nonlinear control of an industrial distillation column by exact linearization
(1989) Allgöwer, Frank; Sax, Antonius; Gilles, Ernst Dieter
-
Open Access
Nonlinear control of high purity distillation columns
(1994) Groebel, Markus; Allgöwer, Frank; Storz, Markus; Gilles, Ernst Dieter
Two simple models of distillation columns are studied to investigate their suitability for the practical use with exact I/O-linearization. An extension of exact I/O-linearization, the asymptotically exact I/O-linearization is applied to the control of a high purity distillation column, using one of these models to derive the static state feedback law. Simulation studies demonstrate the advantage of asymptotically exact I/O-linearization versus classical exact I/O-linearization techniques. Experimental results show the excellent performance of asymptotically exact I/O-linearization using a simple distillation model.
Open Access
On nonlinear systems with poorly behaved zero dynamics
(1992) Doyle, Frank J.; Allgöwer, Frank; Oliveira, Simone Loureiro de; Gilles, Ernst Dieter; Morari, Manfred
The present work adresses the problem of synthesizing nonlinear state feedback controllers for nonlinear, nonminimum-phase processes in three different ways. The first approach consists of a partial linearization which preserves stability by using an approximate stable/anti-stable factorization. The second technique can be viewed as an inner-outer factorization based approach. And, finally, in the single-output case, it is shown (through an example) that stabilization of the internal dynamics of a nonminimum-phase system can be achieved by using an additional input if this is feasible in practice. In this case, the manipulated variables have different roles, i.e., one is chosen such as to input/output feedback linearize the system and the second is used to locally stabilize the resulting nonminimum-phase internal dynamics.