TY - JOUR A1 - Lemoine-Nava, Roberto A1 - Walter, Sebastian F. A1 - Körkel, Stefan A1 - Engell, Sebastian T1 - Online Optimal Experiment Design: Reduction of the Number of Variables JF - IFAC-PapersOnLine N2 - In this work, a method for reducing the number of degrees of freedom in online optimal dynamic experiment design problems for systems described by differential equations is proposed. The online problems are posed such that only the inputs which extend an operation policy resulting from an experiment designed offline are optimized. This is done by formulating them as multiple experiment designs, considering explicitly the information of the experiment designed offline and possible time delays unknown a priori. The performance of the method is shown for the case of the separation of isopropanolol isomers in a Simulated Moving Bed plant. KW - Optimal experiment design KW - Large scale systems KW - Decomposition methods KW - Partial differential equations KW - Time delay KW - Chromatography KW - Simulated Moving Bed process Y1 - 2016 U6 - https://doi.org/10.1016/j.ifacol.2016.07.302 VL - 49 IS - 7 SP - 889 EP - 894 PB - Elsevier ER - TY - JOUR A1 - Weber, Karsten A1 - Dendorfer, Sebastian A1 - Süß, Franz A1 - Kubowitsch, Simone A1 - Schratzenstaller, Thomas A1 - Haug, Sonja A1 - Mohr, Christa A1 - Kiesl, Hans A1 - Drechsler, Jörg A1 - Westner, Markus A1 - Kobus, Jörn A1 - Schubert, Martin J. W. A1 - Zenger, Stefan A1 - Pietsch, Alexander A1 - Weiß, Josef A1 - Hinterseer, Sebastian A1 - Schieck, Roland A1 - Scherzinger, Stefanie A1 - Klettke, Meike A1 - Ringlstetter, Andreas A1 - Störl, Uta A1 - Bissyandé, Tegawendé F. A1 - Seeburger, Achim A1 - Schindler, Timo A1 - Ramsauer, Ralf A1 - Kiszka, Jan A1 - Kölbl, Andreas A1 - Lohmann, Daniel A1 - Mauerer, Wolfgang A1 - Maier, Johannes A1 - Scorna, Ulrike A1 - Palm, Christoph A1 - Soska, Alexander A1 - Mottok, Jürgen A1 - Ellermeier, Andreas A1 - Vögele, Daniel A1 - Hierl, Stefan A1 - Briem, Ulrich A1 - Buschmann, Knut A1 - Ehrlich, Ingo A1 - Pongratz, Christian A1 - Pielmeier, Benjamin A1 - Tyroller, Quirin A1 - Monkman, Gareth J. A1 - Gut, Franz A1 - Roth, Carina A1 - Hausler, Peter A1 - Bierl, Rudolf A1 - Prommesberger, Christian A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Schreiner, Rupert A1 - Huang, Yifeng A1 - She, Juncong A1 - Ottl, Andreas A1 - Rieger, Walter A1 - Kraml, Agnes A1 - Poxleitner, Thomas A1 - Hofer, Simon A1 - Heisterkamp, Benjamin A1 - Lerch, Maximilian A1 - Sammer, Nike A1 - Golde, Olivia A1 - Wellnitz, Felix A1 - Schmid, Sandra A1 - Muntschick, Claudia A1 - Kusterle, Wolfgang A1 - Paric, Ivan A1 - Brückl, Oliver A1 - Haslbeck, Matthias A1 - Schmidt, Ottfried A1 - Schwanzer, Peter A1 - Rabl, Hans-Peter A1 - Sterner, Michael A1 - Bauer, Franz A1 - Steinmann, Sven A1 - Eckert, Fabian A1 - Hofrichter, Andreas ED - Baier, Wolfgang T1 - Forschungsbericht 2017 T3 - Forschungsberichte der OTH Regensburg - 2017 KW - Forschung KW - Forschungsbericht Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-13835 SN - 978-3-9818209-3-5 CY - Regensburg ER - TY - JOUR A1 - Barz, Tilman A1 - Seliger, Dominik A1 - Marx, Klemens A1 - Sommer, Andreas A1 - Walter, Sebastian F. A1 - Bock, Hans Georg A1 - Koerkel, Stefan T1 - State and state of charge estimation for a latent heat storage JF - Control Engineering Practice N2 - A nonlinear state observer is designed for a thermal energy storage with solid/liquid phase change material (PCM). Using a physical 2D dynamic model, the observer reconstructs transient spatial temperature fields inside the storage and estimates the stored energy and the state of charge. The observer has been successfully tested with a lab-scale latent heat storage with a single pass tube bundle and the phase change material located in a shell around each tube. It turns out that the observer robustly tracks the real process data with as few as four internal PCM temperature sensors. © 2017 Elsevier Ltd. All rights reserved. KW - Heat conduction in cylindrical shell KW - Kalman filter KW - Latent heat thermal energy storage (LHTES) KW - MODEL KW - Nonlinear state observer KW - OF-THE-ART KW - Orthogonal collocation KW - PCM KW - PERFORMANCE ENHANCEMENT TECHNIQUES KW - PHASE-CHANGE MATERIAL KW - POLYETHYLENE KW - Reduced model KW - simulation KW - Solidification KW - State of charge (SOC) KW - SYSTEMS KW - THERMAL-ENERGY STORAGE Y1 - 2018 U6 - https://doi.org/10.1016/j.conengprac.2017.11.006 VL - 72 SP - 151 EP - 166 PB - Pergamon-Elsevier d. ER - TY - JOUR A1 - Jost, Felix A1 - Kudruss, Manuel A1 - Koerkel, Stefan A1 - Walter, Sebastian F. T1 - A computational method for key-performance-indicator-based parameter identification of industrial manipulators JF - Journal of mathematics in Industry N2 - We present a novel derivative-based parameter identification method to improve the precision at the tool center point of an industrial manipulator. The tool center point is directly considered in the optimization as part of the problem formulation as a key performance indicator. Additionally, our proposed method takes collision avoidance as special nonlinear constraints into account and is therefore suitable for industrial use. The performed numerical experiments show that the optimum experimental designs considering key performance indicators during optimization achieve a significant improvement in comparison to other methods. An improvement in terms of precision at the tool center point of 40% to 44% was achieved in experiments with three KUKA robots and 90 notional manipulator models compared to the heuristic experimental designs chosen by an experimenter as well as 10% to 19% compared to an existing state-of-the-art method. KW - ACCURACY KW - collision avoidance KW - CONFIGURATIONS KW - industrial manipulators KW - key performance indicator KW - optimum experimental design KW - parameter identification KW - quantity of interest KW - ROBOT CALIBRATION Y1 - 2017 U6 - https://doi.org/10.1186/s13362-017-0039-7 VL - 7 IS - 9 PB - Springer Nature ER - TY - JOUR A1 - Walter, Sebastian F. A1 - Schmidt, Andrea A1 - Körkel, Stefan T1 - Adjoint-based optimization of experimental designs with many control variables JF - Journal of Process Control N2 - We propose a method for an efficient optimization of experimental designs, using a combination of discrete adjoint computations, Taylor arithmetic and matrix calculus. Compared to the state of the art of using finite differences or the forward mode of automatic differentiation, our proposed approach leads to a reduction of the relative temporal complexity from linear to constant time in the number of control variables and measurement weights. We demonstrate that the advantageous complexity results are not only of theoretical nature, but lead to significant speedups in practice as well. With our implementation we are very close to the theoretical bound of the cheap gradient principle. We present one academic (spatially discretized heat equation) and two industrial application examples (biochemical process/Diesel-oxidation catalysis process) where we achieve speedups that range between 10 and 100. In addition to our core results, we also describe an efficient adjoint approach for the treatment of differential algebraic equations and present adjoint formulas for constrained least-squares problems. KW - Automatic differentiation KW - Constrained least-squares KW - Differential algebraic equation KW - Optimum experimental design KW - Reverse mode Y1 - 2014 U6 - https://doi.org/10.1016/j.jprocont.2014.06.019 SN - 0959-1524 VL - 24 IS - 10 SP - 1504 EP - 1515 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Barz, Tilman A1 - López C., Diana C. A1 - Körkel, Stefan A1 - Walter, Sebastian F. T1 - Real-time adaptive input design for the determination of competitive adsorption isotherms in liquid chromatography JF - Computers and Chemical Engineering N2 - The adaptive input design (also called online redesign of experiments) for parameter estimation is very effective for the compensation of uncertainties in nonlinear processes. Moreover, it enables substantial savings in experimental effort and greater reliability in modeling. We present theoretical details and experimental results from the real-time adaptive optimal input design for parameter estimation. The case study considers separation of three benzoate by reverse phase liquid chromatography. Following a receding horizon scheme, adaptive D-optimal input designs are generated for a precise determination of competitive adsorption isotherm parameters. Moreover, numerical techniques for the regularization of arising ill-posed problems, e.g. due to scarce measurements, lack of prior information about parameters, low sensitivities and parameter correlations are discussed. The estimated parameter values are successfully validated by Frontal Analysis and the benefits of optimal input designs are highlighted when compared to various standard/heuristic input designs in terms of parameter accuracy and precision. Y1 - 2016 U6 - https://doi.org/10.1016/j.compchemeng.2016.07.009 VL - 94 SP - 104 EP - 116 PB - Elsevier ER -