TY - JOUR A1 - Sitz, Andre A1 - Schwarz, Udo A1 - Kurths, Jürgen T1 - The unscented Kalman filter : a powerful tool for data analysis Y1 - 2004 ER - TY - JOUR A1 - Wessel, Niels A1 - Aßmus, Joerg A1 - Weidermann, Frank A1 - Konvicka, Jan A1 - Nestmann, S. A1 - Neugebauer, R. A1 - Schwarz, Udo A1 - Kurths, Jürgen T1 - Modeling thermal displacements in modular tool systems N2 - In the last decade, there has been an increasing interest in compensating thermally induced errors to improve the manufacturing accuracy of modular tool systems. These modular tool systems are interfaces between spindle and workpiece and consist of several complicatedly formed parts. Their thermal behavior is dominated by nonlinearities, delay and hysteresis effects even in tools with simpler geometry and it is difficult to describe it theoretically. Due to the dominant nonlinear nature of this behavior the so far used linear regression between the temperatures and the displacements is insufficient. Therefore, in this study we test the hypothesis whether we can reliably predict such thermal displacements via nonlinear temperature-displacement regression functions. These functions are estimated firstly from learning measurements using the alternating conditional expectation (ACE) algorithm and then tested on independent data sets. First, we analyze data that were generated by a finite element spindle model. We find that our approach is a powerful tool to describe the relation between temperatures and displacements for simulated data. Next, we analyze the temperature-displacement relationship in a silent real experimental setup, where the tool system is thermally forced. Again, the ACE-algorithm is powerful to estimate the deformation with high precision. The corresponding errors obtained by using the nonlinear regression approach are 10-fold lower in comparison to multiple linear regression analysis. Finally, we investigate the thermal behavior of a modular tool system in a working milling machine and get again promising results. The thermally induced errors can be estimated with 1-2${mu m}$ accuracy using this nonlinear regression analysis. Therefore, this approach seems to be very useful for the development of new modular tool systems. Y1 - 2004 ER - TY - JOUR A1 - Kopitzki, K. A1 - Warnke, P. C. A1 - Saparin, Peter A1 - Kurths, Jürgen A1 - Timmer, Jens T1 - Comment on "Kullback-Leibler and renormalized entropies: Applications to electroencephalograms of epilepsy patients" Y1 - 2002 ER - TY - JOUR A1 - Zhang, H. A1 - Hu, B. A1 - Hu, G. A1 - Ouyang, Q. A1 - Kurths, Jürgen T1 - Turbulence control by developing a spiral wave with a periodic signal injection in the complex Ginzburg-Laundau equation Y1 - 2002 ER - TY - JOUR A1 - Tokuda, I. A1 - Kurths, Jürgen A1 - Rosa, Epaminondas T1 - Learning phase synchronization from nonsynchronized chaotic regimes Y1 - 2002 ER - TY - JOUR A1 - Boccaletti, Stefano A1 - Valladares, D. L. A1 - Kurths, Jürgen T1 - Synchronization of chaotic structurally nonequivalent systems Y1 - 2000 ER - TY - JOUR A1 - Zaks, Michael A. A1 - Park, Eun Hyoung A1 - Kurths, Jürgen T1 - On phase synchronization by periodic force in chaotic oscillators with saddle equilibria Y1 - 2000 ER - TY - JOUR A1 - Zhou, Changsong A1 - Kurths, Jürgen A1 - Kiss, Istvan Z. A1 - Hudson, J. L. T1 - Noise-enhanced phase synchronization of chaotic oscillators Y1 - 2002 ER - TY - JOUR A1 - Boccaletti, Stefano A1 - Kurths, Jürgen A1 - Osipov, Grigory V. T1 - The synchronization of chaotic systems Y1 - 2002 ER -