Electronic Measurement and Diagnostic Technology

Technische Universität Berlin Faculty IV Annual Report 2007 Electronic Measurement and Diagnostic Technology Technische Universität Berlin Prof. Dr.-Ing. Clemens Gühmann Department of Electronic Measurement and Diagnostic Technology Sekr. EN 13, Einsteinufer 17 10587 Berlin, Germany Phone: +49 30 314-22280 http://www.mdt.tu-berlin.de

Dear ladies and gentlemen, dear colleagues and friends, this year was marked by radical changes in teaching. We switched from the diploma study courses to bachelor and master courses. With the financial support from the TU OWL program (Offensive Wissen durch Lernen), with new ideas from our research assistants and student workers, and the active support of our workshop we could modernise our measurement labs and we could also build a new lab for automotive software development. Meanwhile the Berliner Senat approved the master course in Automotive Systems so that we can start in spring with lessons and labs in automotive engineering. In contrast to the teaching activities the research projects were marked by continuity. In this annual report you will find an overall view in: Wireless Sensor Network Diagnosis and Pattern Recognition Modelling and Simulation Automated Analysis of Vehicle Measurement Data I hope you will enjoy reading our report. Perhaps we will meet us in Berlin to discuss face-to-face about modelling, simulation, and testing on our 3 rd conference Simulation and Testing in Algorithm and Software Development for Automotive Electronics. Together with our partner IAV GmbH (Ingenieurgesellschaft Auto und Verkehr) we organise this conference on 26 th and 27 th of May 2008. We welcome Prof. Kai Strunz in our Institute for Energy and Automation Technology. Since September 2007 he is the head of the Chair of Sustainable Electric Networks and Sources of Energy (SENSE). We found also Prof. Kaase s successor in the section of lighting engineering. Dr.-Ing. Stephan Völker from the Light Laboratory (L-Lab) in Paderborn get a call and we hope he will follow it. Unfortunately Prof. Bernet (Power Electronics) left the TU Berlin towards TU Dresden. We wish him good luck. I would like to thank the whole MDT-Team. All of them did an excellent job in different research projects and in teaching. I wish you and your families a blessed Christmas and a Happy New Year, Clemens Gühmann 1

Wavelet Application Group Stephan Rein and Stephan Lehmann (Publications 2007: [8]) The Wavelet Application Group has worked on the improvement of the Wavelet Lab, where the students now learn how to apply some Wavelet algorithms for picture compression on an embedded system. The students use novel signal-controller boards with a camera and a memory card. Stephan Lehmann has worked on an improved library for the camera and the SD-memory-card and is now finalising a low-cost developerkit for students and researchers. The set is available to our students for 50 e. Stephan Lehmann also works on the Spisa user-interface that allows to transfer data and tasks to the sensor network and to get the required information from the network. Stephan Rein works on a wavelet picture compression algorithm for Spisa. In this year Zakaria Kasmi, Cornelius Tetzner, Sinan Akay, and Daniel Gühne completed their thesis. Zakaria Kasmi programmed a routing algorithm for sensor networks. Cornelius Tetzner applied a web-server on a signalcontroller. Sinan Akay presented a system for pedestrian navigation using acceleration and compass sensors. Daniel Gühne realised a system for a time division multiple access (TDMA) protocol that allows for streaming applications. It could transfer compressed voice from multiple Spisa-sensors in real-time. Since summer 2007, the Wavelet Application Group also offers a class on Mobile Phone Programming. Mobile phones may be employed as user interface and data gateway for sensor networks in the future, see [8] for more details. Sequence Analysing Steffen Kühn (Publications 2007: [1, 2]) For various applications powerful and efficient pattern recognition methods for sequence analysis are necessary, for example in speech, picture, and handwriting recognition, for the analysis of gene 2

sequences, for the detection of computer viruses, and as well as for the recognition of knocking combustions in Otto engines. At the moment hidden Markov models (HMMs) are state of the art for some of those problems. In 2007 the development of an alternative method for sequence recognition was finished. Similar to HMMs the new stochastic method is appropriate to find noisy and non-linear stretched patterns in digital data sequences, but surpasses this standard method in performance, simplicity, and exactness. The improvements are due to a special preparation of the given sample data-set for the model parameter estimation so that it is no longer necessary to use complex two stage stochastic processes like HMMs. The method was filed as patent [2]. First applications are found in image analysis for fault detection. At the moment we are developing an embedded platform for knock detection using this new method. Modelling, Simulation and Automated Data Analysis of Double Clutch Transmissions Henrik Isernhagen (Publications 2007: [1]) Nowadays, more and more new cars are assembled with double clutch transmission because of efficiency, drive comfort, and uninterrupted power shifts. A double clutch transmission contains two parallel transmission shafts with two parallel clutches. The clutches can be either dry clutches or multi-disc (wet) clutches. The different gears are mounted alternately on the two transmission shafts. The first shaft contains the odd gears with the reverse gear, and the second shaft contains the even gears. There are uninterrupted power shifts possible by reason of the two different clutches with the accordant shafts. The correct control of the two clutches is very important in view to the different shifting processes. At this point it is necessary to distinguish between upshifts and downshifts as well as pulling power and pushing power of the powertrain. Controlling errors can result in bad shiftings, e. g., in form of revolution speed droppings, break outs, or oscillations. In cooperation with the IAV GmbH a software was developed for an automated analysis of vehicle measurement data [1]. Here, recorded measurement data can be evaluated automatically to different system 3

and failure states. The aim is to use this software to detect controlling errors of double clutch transmissions. Normally, data from the CAN-Bus would be analysed. But, the parametrisation of this analysis system requires measurement data of good and bad shifting processes. Consequently, we develop different models of double clutch transmissions in Modelica /Dymola at the Department of Electronic Measurement and Diagnostic Technology. The aim of the modelling and simulation process is to get data of shift processes of different quality. For this it is necessary to build models with different levels of details. This task has to be differentiated between the physical modelling of the double clutch transmission and the modelling of the control structure. A basic model of a double clutch transmission and its insertion in the vehicle structure is shown in the cover figure. By varying the driver models it is possible to drive miscellaneous drive and shifting cycles, e. g., in form of a table with acceleration and brake pedal positions or following a velocity profile in form of predefined drive cycles. Finally, the automated measurement data analysis system should be parametrised using the simulation results. Beside the evaluation of shift processes it should be possible to analyse further control and measurement signals of double clutch transmissions. The aim is to use the measurement data analysis for the detection and assessment of bad shiftings in real vehicle measurement data. Fault Simulations of Electric Drives Dietmar Winkler (Publications 2007: [11]) This project continues work which started off as the Test Bench of the Future project. In the end of 2006 it was already clear that the focus of that project will shift from the calibration of combustion engines to the investigations of impacts of electrical faults in electric drives. Electric drives are more and more replacing various mechanical parts in a modern car. Everything tends to be realised in a x-bywire approach giving the customer a higher degree of safety (e. g., because of active control loops) and comfort. But not only the xby-wire technology employs lots of small electric drives. Hybrid electric vehicles (HEV) have become part of the current or near future product line of any major car manufacturer. 4

For the investigations of faults in electric drives a new open-source modelling library based on Modelica called freefoclib is being developed [10]. The main objective of that library is to have a framework for both, field-oriented controllers and machine models for fault generation. Faults such like winding short-cuts (e. g., by over temperature) or power failure in part of the windings (cut-off of supply connectors) can be simulated and interpreted. The simulation results can then be used to identify for example unacceptable torque ripples on the drive train of overload of the power-electronics. One example application of the freefoclib was presented at the 48 th Scandinavian Conference on Simulation and Modeling (SIMS 2007). Future plans involve the verification of the fault models by matching the simulation results with test results from an electric machine testbench and the investigation of potential ways to make the models suitable for real-time simulations. Fault Detection and Diagnosis of Electric Drives Using Wavelet Based Analysis Ms. Wang Jine (Ph.D.) & cand.-ing. Eduard Bakhach With increasing demands for automobiles in drive comfort, fuel economy, and pollutant emissions, mechatronic systems with large scale integration become more and more complex. Therefore fault diagnosis systems for electrical systems especially electrical machines are a matter of particular interest. The target of the project Fault Detection and Diagnosis of Electric Drives Using Wavelet Based Analysis is to design a digital filter with the wavelet transformation (WT) in order to analyse and diagnose signals in real-time. Compared with Fourier transformation, the WT supports the analysing of non stationary and high frequency signals better. The filter design includes a sub-band coding by which the signal is split into signals with different spectra. To test the filter algorithm it was necessary to build detailed simulation models of faulty and faultless electrical machines including a control unit using the Modelica library freefoclib [10]. So far, the setup of the Modelica /Dymola simulation model of the hardware components (see Fig. 1), as well as the MATLAB /Simulink algorithm to analyse the current, voltage, and 5

Figure 1: Project tasks: modeling, filter design and signal analyses engine speed signals with the Discrete Wavelet Transform (DWT) has been completed. The next steps are the optimisation of the wavelet transformation for real-time applications and the feature generation to complete the diagnosis system which should run in real-time on an automotive electronic control unit. Publications in 2007 [1] H. Isernhagen, H. Neemann, S. Kühn, and C. Gühmann. Intelligent Signal Processing in an Automated Measurement Data Analysis System. In Proceedings of the 2007 IEEE Symposium on Computational Intelligence in Image and Signal Processing (CIISP 2007), Honolulu, USA, pages 83 87. IEEE, 2007. [2] S. Kühn and C. Gühmann. Erfindung 102007036277.5: Verfahren und Vorrichtung zur automatischen Mustererkennung. Misc, 2007. 6

[3] S. Lachmann. Reduzierung des Einflusses von Störgeräuschen in Klopfregelsystemen mittels Blinder Quellentrennung. PhD thesis, Technische Universität Berlin, 2007. [4] S. Lachmann and C. Gühmann. Unterdrückung von Störgeräuschen bei der Klopferkennung durch Einsatz der Blinden Quellentrennung. In 7. Internationales Stuttgarter Symposium Automobil- und Motorentechnik, 2007. [5] H. Nahrstaedt and C. Gühmann. Data Based Modelling of Engine Dynamics. In Design of Experiments (DOE) in Engine Development, III. expert Verlag, 2007. [6] S. Rebeschieß, T. Liebezeit, U. Bazarsuren, and C. Gühmann. Automatisierter Closed-Loop-Testprozess für Steuergerätefunktionen. ATZ elektronik, 01(01):34 41, 2007. [7] S. Rebeschieß, B. Uzmee, T. Liebezeit, and C. Gühmann. Automatisierter Closed-Loop-Testprozess für eingebettete Steuergerätefunktionen. In 6. Symposium Steuerungssysteme für den Antriebsstrang von Kraftfahrzeugen, pages 104 141. IAV GmbH, Ingenieurgesellschaft Auto und Verkehr, 2007. [8] S. Rein, C. Gühmann, and F. Fitzek. Sensor Networks for Distributive Computing, chapter VII-21, pages 397 409. Springer, 2007. [9] H. Schumann, A. Berres, O. Maibaum, and T. Liebezeit. Simulation-Based Testing of Small Satellite Attitude Control Systems. Small Satellites for Earth Observation. In Digest of the 6th International Symposium of the International Academy of Astronautics, pages 151 154. Wissenschaft und Technik Verlag Berlin, 2007. [10] D. Winkler, E. Bakhach, F. Döring, and S. Rinderer. freefoclib - A free Field-Oriented Control library for Modelica. unreleased, see www.freefoclib.org for any news. Due in, Spring 2008. [11] D. Winkler and C. Gühmann. Modelling of Electrical Faults Using Modelica. In Proceedings of The 48th Scandinavian Conference on Simulation and Modeling (SIMS 2007), 2007. 7

Our Team Head of Department Prof. Dr.-Ing. Clemens Gühmann Sekr. EN 13 Ms. Brigitte Auerbach Research Assistants Dipl.-Ing. Uzmee Bazarsuren (until March 2007) Dipl.-Ing. Henrik Isernhagen Dipl.-Ing. Steffen Kühn Dr.-Ing. Thomas Liebezeit (until March 2007) Dipl.-Ing. Stephan Rein Dipl.-Ing. Dietmar Winkler Doctorands Dipl.-Ing. Uzmee Bazarsuren (IAV GmbH) Dipl.-Ing. Stev Gerson (IAV GmbH) Dipl.-Ing. Thomas Habbath (Bayer-Schering) Dipl.-Ing. Wei Hu (Robert Bosch GmbH) Dipl.-Ing. Geng Lai (Robert Bosch GmbH) Dipl.-Ing. Felix Matthies (IAV GmbH) Dipl.-Ing. Adrian Nessler (IAV GmbH) Dipl.-Ing. Guido Wachsmuth (IAV GmbH) Guest Researchers Ms. Wang Jine (Ph.D.), (since July 2007) Visiting Lecturers Dr.-Ing. Jörg Beilharz Dr.-Ing. Carsten Haukap Dr.-Ing. Thomas Offer Dr.-Ing. Thieß-Maguns Wolter 8

Tutors Measurement Laboratory Mr. Mathias Janke, Mr. Lahoussine El Mekhantar, Mr. Holger Nahrstaedt, Ms. Amra Mujagic, Mr. Daniel Smolin, Ms. Xiaonan Sun OWL - Student Assistants Ms. Sarah Fell, Mr. Sven Kriener, Mr. Stephan Lehmann, Mr. Sebastian Nowoisky, Mr. Alexander Wiener Student Research Assistants Mr. Eduard Bakhach, Mr. Felix Böckelmann, Ms. Alexandra Mehlhase Offices Ms. Edeltraud Esser (EN 3 EMSP) Ms. Brigitte Auerbach (EN 13 MDT) Institute Engineers (EMSP & MDT) Dipl.-Ing. Frank Baeumer Dipl.-Ing. Rüdiger Seidel Electronic Service (EMSP & MDT) Mr. Michael Hackbarth Mr. Hans-Ulrich Timm Mechatronic Workshop (EMSP & MDT) Mr. Peter Jaeck Mr. Uwe Kurlbaum 9

Courses summer term 2007 Lecture Measurement Data Processing Project Course Measurement Data Processing with Wavelets Laboratory Electronic Measurement Techniques (MT I) Laboratory Measurement Data Processing Lecture Introduction to Automobile Electronics Laboratory Introduction to Automobile Electronics Lecture Control and Regulation of Automotive Power Trains Seminar Mobile Phone Programming Seminar Graduation seminar Measurement Technique Projects Measurement Data Processing, Simulation, and Technical Diagnostics winter term 2007/2008 Lecture Basics of Electronic Measurement Techniques (MT I) Tutorial Basics of Electronic Measurement Techniques (MT I) Laboratory Basics of Electronic Measurement Techniques (MT I) Lecture Modelling and Real-Time Simulation Lecture Pattern Recognition and Technical Diagnostics Project Course Pattern Recognition and Technical Diagnostics Seminar Mobile Phone Programming Seminar Projects Graduation seminar Measurement Technique Measurement Data Processing, Simulation, and Technical Diagnostics Combined organised courses of Prof. Obermeier and Prof. Gühmann Laboratory Laboratory Laboratory Electronic Measurement Techniques Measurement Data Processing Sensors 10