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Object-Oriented Graph Grammars for Computational Design Synthesis

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Object-Oriented Graph Grammars for Computational Design Synthesis TECHNISCHE UNIVERSITÄT MÜNCHEN Lehrstuhl für Produktentwicklung Object-Oriented Graph Grammars for Computational Design Synthesis Bergen Helms Vollständiger Abdruck der von der Fakultät für Maschinenwesen der Technischen Universität München zur Erlangung des akademischen Grades eines Doktor-Ingenieurs genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. rer. nat. Dr. h.c. Ulrich Walter Prüfer der Dissertation: 1. Univ.-Prof. Kristina Shea, Ph.D., Eidgenössische Technische Hochschule Zürich, Schweiz 2. Univ.-Prof. Dr.-Ing. Martin Eigner, Technische Universität Kaiserlsautern 3. Univ.-Prof. Dr.-Ing. Udo Lindemann Die Dissertation wurde am 20.09.2012 bei der Technischen Universität München eingereicht und durch die Fakultät für Maschinenwesen am 06.02.2013 angenommen. Abstract Conceptual design is an early design phase that is acknowledged as particularly critical. Its goal is the determination of the product’s essential characteristics that meet the given requirements. Conceptual design is characterized by high uncertainty resulting from lacking knowledge about the future prod- uct that makes it difficult to evaluate design quality and to systematically explore the set of solutions. Computational Design Synthesis (CDS) aims at supporting conceptual design through formalization and automation of knowledge-intensive design tasks. However, CDS still has little acceptance in industry due to the high effort required for knowledge and task formalization, the limited scope of application, the lack of reuse of existing paper-based design knowledge, the lack of modeling standards and tool integration, and the low maturity of software tools. The potential of CDS to increase development efficiency and innovative power motivates addressing these problems. This thesis contributes to the goal of increasing the applicability of CDS in every day design practice with the development and implementation of a hy- brid knowledge representation, termed object-oriented graph grammar, and an approach to automatically formalize engineering knowledge from design catalogs. Object-oriented graph grammars enable the computational synthesis of product architectures on multi- ple levels of abstraction, i. e. Function, Behavior and Structure. This hybrid knowledge representation allows to capture declarative knowledge in a port-based metamodel and to formulate generic, procedural design rules in a graph grammar. The object-oriented graph grammar approach is implemented in the modular, open-source and platform-independent software booggie. A formal language definition repre- sents the foundation for tool integration through model transformation. A complementary approach is developed to characterize and formalize physical effects contained in design catalogs. Through an auto- mated analysis of the equation structure, abstraction ports are assigned to physical effects and represent valid mappings between functions and physical effects. Through the hybrid knowledge representation of object-oriented graph grammars, advances in terms of efficiency and effectiveness of the knowledge formalization are achieved. These contributions are vali- dated through the synthesis of a solution space of automotive hybrid powertrains. The impact of evolv- ing engineering knowledge on the solution space is shown and noteable solutions are identified through the search for specific solution characteristics. The computational generation of aircraft cabin layouts validates the practical usability of object-oriented graph grammars as implemented in booggie in an in- dustrial case study. The automated, equation-based formalization of physical effects makes paper-based engineering knowledge available for CDS. The advantage to computationally reusing this knowledge is validated with the formalization of the physical effects of two design catalogs and a separate software prototype that searches suitable physical effects for a given function. The contributions achieved in this work support the efforts to bring CDS approaches into use in every day design practice. Besides an increase of the software maturity, future work should include the in- tegration of object-oriented graph grammars and the automated assignment of abstraction ports in one implementation. The extension of the synthesis of product architectures towards parametric synthesis and design evaluation using simulation should be addressed as well. Further, the incorporation of logical reasoners could enable the solution of logical port-matching problems and using model transformation, the transformation to other modeling languages, e. g. SysML, could be realized. Acknowledgments This work results from my occupation as a researcher in the Virtual Product Development Group at the Institute of Product Development at the Technische Universität München from July 2007 to June 2012. Firstly, I would like to thank my doctoral advisor Prof. Kristina Shea for her intense support of my research and confidence in my work. This work would not have been possible without our numerous, valuable – sometimes very demanding – research meetings. Particularly our three-day finalization session was highly valuable for the compilation of this thesis. I want to thank Prof. Martin Eigner for his contribution as second advisor. I always enjoyed the scientific discussions with him and his group members. I also want to thank Prof. Ulrich Walter who graciously accepted to act as chairman of the examination board on short notice. My gratitude also goes to my third advisor, Prof. Udo Lindemann, for the trust he placed in my work and for offering me a productive and pleasant working environment at the Institute of Product Development. I always felt part of the overall institute and enjoyed the opportunity to gain many deep insights into design research. I would also like to extend my gratitude to all of my colleagues at the Institute of Product Development for making my research life not only a fruitful but also a humorous, inspiring and perspective broadening venture. In particular, the deep discussions, collegial cooperation and unforgettable moments with Dr. David Hellenbrand, Dr. Clemens Hepperle, Arne Herberg, Dr. Frank Hoisl, Stefan Langer, Torsten Metzler and Clemens Münzer made it a pleasure for me to face the academic challenges and to see the humor in the everyday absurdities of research life. Dr. Markus Mörtl greatly helped to cope with the daily bureaucratic hurdles. I would also like to thank Karim Bin-Humam and Dr. Iestyn Jowers who helped me with the pitfalls of the English language. I owe a mille grazie to il mio padrino Dr. Markus Petermann and la mia figlioccia Katharina Helten: "Ihr seid’s just leiwand!" A special thanks goes to Prof. Chris Paredis at the Georgia Institute of Technology who made it possible for me to spend four memorable months in Atlanta. I would also like to thank Sebastian Herzig, Ben Lee, Jiten Patel and Dr. Axel Reichwein for their hospitality, the many joint activities and for making my adventure in the USA special in so many ways. In addition, I would like to thank all my students who helped me in developing my ideas further, trying out new concepts and developing the software booggie. Particularly, I must thank Karim Bin-Humam, Philip Daubmeier, Oleksandr Golovatenko, Peter Grüner, Thomas Hentschel, Franziskus Karsunke, Philip Lorenz, Ferdinand Mayet, Clemens Münzer and Hansjörg Schultheiß. Special thanks goes to my girlfriend Ina who was patient and compassionate in the most trying times of my thesis writing. She was a great discussion partner in difficult moments and motivated me to finalize the thesis writing in a reasonable time frame. Finally, I am very grateful to my parents and my sister. Their unwavering belief in my abilities and their multifaceted support empowered me to successfully carry out this work. Garching, March 2013 Bergen Helms The following publications are part of the work presented in this thesis: Helms, B.; Shea, K.; Hoisl, F.: A Framework for Computational Design Synthesis Based on Graph- Grammars and Function-Behavior-Structure. In: ASME 2009 International Design Engineering Tech- nical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2009, pp. 841–851. San Diego, USA 2009. Helms, B.; Shea, K.: Object-Oriented Concepts for Computational Design Synthesis. In: 11th Interna- tional Design Conference, DESIGN 2010. Dubrovnik, Croatia 2010. Helms, B.; Schultheiß, H.; Shea, K.: Automated Assignment of Physical Effects to Functions Using Ports Based on Bond Graphs. In: ASME 2011 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2011. Washington DC, USA. Helms, B.; Shea, K.: Computational Synthesis of Product Architectures Based on Object-Oriented Graph Grammars. Journal of Mechanical Design 134 (2012) 2, pp. 021008-1 – 021008-14. ISSN: 10500472. Contents 1 Introduction 1 1.1 Motivation and problem description.............................. 3 1.2 Objectives and expected contributions............................. 6 1.3 Thesis structure ........................................ 10 2 Computational design synthesis for supporting conceptual design 13 2.1 The importance of representation for CDS .......................... 14 2.2 Overview of design representations.............................. 16 2.2.1 Function......................................... 19 2.2.2 Behavior......................................... 23 2.2.3 Structure......................................... 24 2.2.4 Reflections on design representations.........................
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