Institute of Applied MechanicsDevelopment, simulation and experimental investigation of complex dynamical and mechatronical systems

n The Institute of Applied Mechanics is a leading research center in the dynamics of mechanical and robotic systems. The core of its activities focus on the development of novel simulation and experimental techniques for efficient analysis of complex structural dynamics, and on the design, construction and control of advanced robotic machines.

Prof. dr. ir. Daniel Rixen

Contact

www.amm.mw.tum.derixen@tum.dePhone +49.89.289.15220

CROPS manipulator for auto- mated harvesting

The research is organized in three focus areas: Robotics and Mechatronics, Dynamic Simulation and Numerical Techniques, and Experimental Dynamics. Each research

Robotics and Mechatronics

Mechatronics is the combination of mechanical, electrical and informatics systems. A focus of this field lies on the actuation of multibody dynamical systems and vibrating structures in order to achieve specific functions. One example of such systems are robots which are investigated at our institute.Our institute has a long tradition indesigning, constructing and controlling robots for novel applications. Based on our experience in autonomous legged robots, our institute has developed a high performance humanoid robot (LOLA) in recent years.Working in an interdisciplinary team, we combine techniques from informatics, electronics and mechanics to advance the overall system performance on real world walking scenarios. Our focus lies on the development of model-based methodsfor biped walking which are not restricted to one specific robot or scenario. Current research projects include environment rec- ognition and modeling, trajectory planning and walking control.The institute’s expertise in robotics has alsobeen applied to other fields: In September2014 the EU-project CROPS was success- fully finished by developing in collaboration with an international consortium the world’s first autonomous harvesting robot forsweet pepper in greenhouses. Its corecomponent was created at our institute; the

multipurpose, modular redundant manipu- lator arm. With up to 9 degrees of freedom, it is specifically designed for harvesting sweet peppers, apples or the precise spraying of grapes. In addition to the opti-

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group bundles specific expertise, monitors international advances and actively discusses the future research directions.

LOLA, the humanoid robot

mization of the kinematics and mechatronic design, our research also included motion planning based on tactile feedback for operations in cluttered environments such as greenhouses.Another area, in which our institute collabor- ates with the Department of Orthopedics and Sports Orthopedics, is the investigative manipulation of biologic joints. An experi- mental test rig has been developed, which combines adaptive trajectory planning and compliant motion control schemes at high frequencies (4000 Hz) to actuate biologic joints utilizing a robotic arm and thereby analyze their spatial biomechanical behavior. This technique aims at improving the design

of joint replacements (endoprosthesis). Furthermore, the robotics group has proven its worth at the European Robotics Chal- lenge; our institute won the first stage by developing a powerful software framework for the autonomous operation of a mobile robot platform in an industrial scenario.

Projectsn Real-time planning for flexible

walking of a humanoid robot (DFG)

n Robust walking for a humanoid robot

under disturbances (DFG)n Gait control of a humanoid robot in

uneven terrain (DAAD)n CROPS – Clever Robots for Crops:

motion planning for redundant mani- pulators and tactile feedback (EU-FP7, internal)

n Multi-contact planning and control ofbiped walking robots (internal)

n Adaptive force/position control of a robot for investigative manipulation of human joints (MRI)

STÄUBLI RX90B manipulatorfor investigative manipulation of biologic jointsDynamic Simulation and Numerical Techniques

Designing and optimizing high-techsystems necessitates accurate and efficient modeling. The expertise and research focus of the institute is mainly in model reduction aspects, parallel computing strategiesand numerical techniques simulatingthe dynamic of contact between bodies,including lubrication through films.To obtain accurate dynamical system models multiphysical effects need to be included for instance to account forlubrication films (elasto-hydrodynamics), forvibro-acoustic interaction or for electromag- netical coupling.Models used to analyze the dynamics of structures often contain several millions of degrees of freedom. We develop methods to characterize the dynamics of linear and non-linear structural models with only a reduced set of unknowns so that modelscan be used for optimization, design valida- tion or as flexible components in multibody dynamic simulations.In order to use the power of modernmultiprocessor computers, we develop solution algorithms based on the paradigm of domain decomposition; if the problemis partitioned in different domains (regions of a structural model), the solution is

found by iterating on the interface solution while

the behavior in the domains are computed independently by different processors.We improve those methods to make them robust for real-life problems that include for instance high heterogeneities or complex dynamics.

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Interaction between rotating shaft and structural dynamics (top) through pressure in lubrication film (bottom)

Multiphysical system model of a common rail injector

Projectsn Dual substructuring techniques in linear

and multibody dynamics (internal)

n Varying manifolds as reduction basis for geometrically non-linear structures (internal)

n Domain decomposition techniques fordynamic problems (internal)

n FETI method for non-linear multibody dynamics (internal)

n Validation of a pushbelt continuouslyvariable transmission using multibody dynamics (Bosch Transmission Tech- nology BV)

n Elasto-hydrodynamic lubricated con-tacts in multibody dynamical systems(internal)

n Modeling of common-rail injectors forfaults detection and control (DFG)

n Efficient simulation and analysis of flexible multibody systems with friction and impacts (internal)

n Aerodynamic noise predictionof treaded tires using a hybridaero-acoustic methodology (NationalScience Foundation Luxemburg)

n Modeling of gears with defects insystem descriptions (DLR)

n NVH of turbos: floating-ring bearings and rotordynamics modeling (MHI Equipment Europe BV)

n Electromagnetic coupling in the dyna-mics of generator in direct-drive windturbines (XEMC Darwind BV)

n High performance simulation of space- time multiscale nonlinear problems (TUM)

Experimental Dynamics

Dynamic testing is regularly performed in our labs in order to validate models and test constructions. In addition experimental dynamic techniques are part of our research where we improveidentification methods. Within the projectKonRAT (Rocket Engine Componentsfor Aerospace Transport Systems) liquid oxygen turbo pumps are analyzed. Tech- niques to characterize the rotor dynamics as well as the dynamic behavior of seals and bearings are developed; combining reduced component models, validatedon several test rigs, the influences suchas seal instabilities and bearing effects on the turbo pump rotor system can be determined. Another important research topic is experimental substructuring; based on the measured dynamics of components, a full model is built numer- ically by specific assembly techniques. Obtaining an accurate assembled numerical model from measured com- ponents requires special

measurement techniques and signal processing steps. With these techniques we enable novel methodologies to investigate for instance noise and vibration propagation in cars.In our lab we test substructuring strate-gies on a

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small wind turbine as part of an

Experimental characterization of test wind turbine components (AM)

international benchmarking activity for substructuring.Sustructuring ideas are also used inso-called real-time hybrid testing. This special hardware-in-the-loop technique numerically simulates structural com- ponents for which models are available, and exchanges in real-time forces and displacements on the interfaces with a real hardware component in the lab. In suchan approach components can be tested in real conditions, where the dynamic inter- actions with the full system is accounted for. We develop special computationaland control strategies based for instance on adaptive feedforward compensation techniques

Projectsn Rotor dynamics for turbo

pumps in space propulsion systems (BaySt- MWMET)

n Real-time substructuring for complex

systems (internal)n Substructuring methodology

for transfer path analysis (BMW)

Rotor test bench with sensors to monitor defects (AM)

n Four-pole models of car subsystems toset component requirements (BMW)

n Experimental substructuring evaluation on an wind turbine testbench (Iranian Ministery of Research, Education and Technology)

n Dynamic Identifying of a multi-meg-awatt turbine direct-drive generator using operational modal analysis (XEMC Darwind BV)

Research Focusn Modeling and simulation of dynamical

systemsn Vibration analysis and rotordynamicsn Mechatronics and roboticsn Experimental dynamics

Competencen Finite element modeling in dynamics n Model reduction and substructuring n Time integration and solversn Multiphysical modelingn Trajectory planning and control of

robotsn Biped robotsn Modal identificationn Operational modal analysis

Infrastructuren Mechanical and electronic workshopn Vibration and dynamic test labn Robotic labn Dynamics teaching lab

Coursesn Technical Mechanics (Statics,

Elasticity and Dynamics)n Technical Mechanics for Electrotech-

niquen Machine Dynamicsn Simulation of Mechatronical Systemsn Mechanical Vibration Labn Vibration Measurement Labn Technical Dynamicsn Robot Dynamicsn Multibody Dynamicsn Structural Dynamicsn Structural Dynamics Labn Experimental Vibration Analysisn Seminars in Applied Mechanics

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Management:Prof. dr. ir. Daniel Rixen, M.Sc., Ordinarius PD Dr.-Ing. habil. Thomas Thümmel, Director

Retired ProfessorsProf. Dr.-Ing. Friedrich PfeifferProf. Dr.-Ing. Heinz Ulbrich

Guest ProfessorProf. dr. ir. Michel Géradin(Humboldt Awardee)

Administrative Staff Manuela Müller-Philipp Rita SchneiderPetra Popp-Münich

Research Scientists Dipl.-Ing. Andreas Bartl Dipl.-Ing. Jörg BaurDr. Alejandro CosimoDipl.-Math. Eva-Maria DewesFabian Gruber, M.Sc. Dipl.-Ing. Kilian Grundl Michael Häußler, M.Sc.Dipl.-Ing. Arne-Christoph HildebrandtDipl.-Ing. Gerald Horst Dipl.-Ing. Benedikt Huber Dipl.-Ing. Andreas Krinner

Dipl.-Ing. Michael Leistner Dipl.-Ing. Johannes Mayet Dipl.-Ing. Julian PfaffDipl.-Ing. Markus RoßnerDipl.-Ing. Johannes Rutzmoser Dr.-Ing. Thorsten Schindler Dipl.-Ing. Christoph Schütz Felix Sygulla, M.Sc.Christian Wagner, M.Sc. Dipl.-Ing. Robert WittmannRob Eling, M.Sc., external candidate(TU Delft)Maarten van der Seijs, M.Sc., external candidate (TU Delft)Dipl.-Ing. Michael Kirschneck, external candidate (TU Delft)Dipl.-Ing. Martin Münster, externalcandidateDipl.-Ing, Constantin von Deimling Frans ven der Linden, M.Sc., external candidateRomain Pennec, M.Sc.Karamooz Morteza, M.Sc. Daniel Wahrmann, M.Sc. Oliver Hofmann, M.Sc.

Technical Staff Simon Gerer Georg König Georg Mayr

Publications 2015

Journal Publications & Booksn Géradin, Michel; Rixen, Daniel J.: Mechanical

Vibrations: Theory and Application to StructuralDynamics – 3rd Edition. Wiley, 2015.

n Bab, S.; Khade, S.E.; Karamooz Mahdiabadi, M.; Shahgholi, M.: Vibration mitigation of a rotating beam under external periodic force using a nonlinear energy sink (NES). Journal of Vibration and Control 125, 2015.

n Baumann, K.; Beitelschmidt, M.; Dresig, H.; Rock-

hausen, L.; Scheffler, M.; Schwabe, J.-H.; Thümmel, T.: Beitelschmidt, Michael; Dresig, Hans (Hrsg.): Maschinendynamik – Aufgaben und Beispiele. Springer Science + Business Media, 2015.

n Benkert, Tim; Krinner, Andreas; Thümmel, Thomas;

Volk, Wolfram: Designing a High-Speed Press with a Six-Bar Linkage Mechanism. Applied Mechanics and Materials, 2015.

n Gosselet, Pierre; Rixen, Daniel; Roux, Francois-

Xavier; Spilla

ne, Nicole: Simultaneous FETI and block FETI: Robust domain decomposition with multiple search directions. International Journal for Numerical Methods in Engineering 104 (10), 2015.

n Géradin, Michel; Rixen, Daniel J.: A ‘Nodeless’ Dual Superelement Formulation for Structural and Multibody Dynamics – Application to Reductionof Contact Problems. International Journal forNumerical Methods in Engineering, 2015.

n Mayet, Johannes; Ulbrich, Heinz: First-order optimal linear and nonlinear detuning of centrifugal pendulum vibration absorbers. Journal of Sound and Vibration 335 (0), 2015, 34-54.n Pfeiffer, Friedrich; Schindler, Thorsten:

Introductionto Dynamics. Springer, 2015.

n Rixen, Daniel J.; Boogaard, Anthonie; Seijs, Maarten V. van der; Schothorst, Gert van; Poel, Tjeerd van der: Vibration source description in substructuring:A theoretical depiction. Mechanical Systems andSignal Processing (60-61), 2015, 498-511.

n Schindler, Thorsten; Rezaei, Shahed; Kursawe, Jochen; Acary, Vincent: Half-explicit timestepping schemes on velocity level based on time-discon- tinuous Galerkin methods. Computer Methods in Applied Mechanics and Engineering 290, 2015,250-276.

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n Tabak, Umut; Rixen, Daniel J.: vibro-Lanczos, a symmetric Lanczos solver for vibro-acoustic simula- tions. International Journal for Numerical Methodsin Engineering, 2015.

Conference Publicationsn Bartl, Andreas; Mayet, Johannes; Rixen, Daniel

J: Adaptive Feedforward Compensation for Real Time Hybrid Testing with Harmonic Excitation. Proceedings of the 11th International Conference on Engineering Vibration, 2015.

n Bartl, Andreas; Rixen, Daniel J: Feasibility of aTransmission Simulator Technique for Dynamic Real Time Substructuring. Proceedings of the 33rd IMAC, Orlando, FL, 2015.

n Eling, Rob; Ostayen, Ron van; Rixen, Daniel: Oil

Flow in Connecting Channels of Floating Ring Bearings. 11. Internationale Tagung Schwingungen in Rotierenden Maschinen (SIRM), 2015.

n Gruber, Fabian M.; Rutzmoser, Johannes B.; Rixen,

Daniel J.: Comparison between primal and dual Craig-Bampton substructure reduction techniques. Proceedings of the 11th International Conference on Engineering Vibration, Ljubljana, Slovenia, 2015.

n Grundl, K.; Schindler, T.; Rixen, D.; Ulbrich, H.;Velde, A. van der; Yildiz, S.: ALE beam formulation using reference dynamics for pushbelt CVTs. ECCOMAS Thematic Conference on Multibody Dynamics, 2015.

n Grundl, Kilian; Schindler, Thorsten; Rixen, Daniel

J.; Ulbrich, Heinz; Velde, Arie v. d.; Yildiz, Semih: Modelling a pushbelt variator. GAMM, 86th Annual Scientific Conference. Springer, 2015.

n Hildebrandt, Arne-Christoph; Wahrmann, Daniel;

Wittmann, Robert; Rixen, Daniel; Buschmann, Thomas: Real-Time Pattern Generation Among Obstacles for Biped Robots. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015.

n Horst, G.; Fritzsche, M.; Rixen, D.: Using an Infrared

Laser in Outer Body Measurement: Feasibility Study. ESB 2015, 21st Congress of the European Society of Biomechanics, 2015.

n Kirschneck, M.; Rixen, D. J.; Polinder, Henk;Ostayen, Ron van: In-Situ Experimental Modal Analysis of a Direct-Drive Wind Turbine Generator. Proceedings of the 33rd IMAC, Orlando, FL, 2015.

n Krinner, A.; Rixen, D.J.: Quasi-Newton methodapplied to elastohydrodynamic lubricated cylindrical joints. ECCOMAS Thematic Conference on Multi- body Dynamics, 2015.

n Krinner, A.; Schindler, T.; Rixen, D. J.: Fluid-Struk-

tur-Kopplung in elastohydrodynamischen Gleit- lagern. 11. Internationale Tagung Schwingungen in rotierenden Maschinen (SIRM), 2015.

n Krinner, Andreas; Schindler, Thorsten; Rixen, Daniel:

Projection formulation of the cavitation problem in elastohydrodynamic lubrication contact. Proc. Appl. Math. Mech. 15, 2015, 57-58.

n Rutzmoser, Johannes B; Gruber, Fabian M; Rixen, Daniel J: A Comparison on Model Order Reduction Techniques for Geometrically Nonlinear Systems Based on a Modal Derivative Approach Using Sub- space Angles. Proceedings of the 11th International Conference on Engineering Vibration, Ljubljana, Slovenia, 2015.n Schindler, Thorsten: A consistent and

efficientframework for the time integration of multibody systems with impacts and friction. ECCOMAS Thematic Conference on Multibody Dynamics,2015.

n Schindler, Thorsten; Mayet, Johannes; Seiwald, Philipp: Impulse-based control of simple oscillators within the nonsmooth mechanics approach. Proc. Appl. Math. Mech. 15, 2015, 73-74.

n Schütz, Christoph; Baur, Jörg; Pfaff, Julian; Bus-

chmann, Thomas; Ulbrich, Heinz: Evaluation of a Direct Optimization Method for Trajectory Planning of a 9-DOF Redundant Fruit-Picking Manipulator. IEEE International Conference on Robotics and Automation (ICRA), Seattle, WA, 2015.

n Schütz, Christoph; Pfaff, Julian; Sygulla, Felix;

Rixen, Daniel; Ulbrich, Heinz: Motion Planning for Redundant Manipulators in Uncertain Environments based on Tactile Feedback. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Hamburg, Germany, 2015.

n Seijs, M.V. van der; Pasma, E.A.; Klerk, D. de;

Rixen, D.J.: A comparison of two component TPA approaches for steering gear noise prediction. Proceedings of the 33rd IMAC, Orlando, FL, 2015.n Thümmel, Thomas; Rossner, Markus;

Ulbrich,Heinz; Rixen, Daniel: Unterscheidung verschiedener Fehlerarten beim modellbasierten Monitoring. 11. Internationale Tagung Schwingungen in Rotierenden Maschinen (SIRM), 2015. Best Paper Award.n Thümmel, Thomas; Wittmann, Robert;

Roßner,Markus: Bewegungsübertragung ohne Zwang – eine Anwendung von Selbstsynchronisation. 11. Kolloquium Getriebetechnik, Garching, Germany,2015.

n Ulbrich, Heinz; Baur, Jörg; Pfaff, Julian; Schütz, Christoph: Design and Realization of a Redundant Modular Multipurpose Agricultural Robot. DINAME2015 – Proceedings of the XVII InternationalSymposium on Dynamic Problems of Mechanics,2015.

n Wittmann, Robert; Hildebrandt, Arne-Christoph; Wahrmann, Daniel; Buschmann, Thomas; Rixen, Daniel: State Estimation for Biped Robots Using Multibody Dynamics. IEEE/RSJ International Con- ference on Intelligent Robots and Systems (IROS), Hamburg, Germany, 2015.n Wittmann, Robert; Hildebrandt, Arne-

Christoph;Wahrmann, Daniel; Rixen, Daniel; Buschmann, Thomas: Real-Time Nonlinear Model Predictive Footstep Optimization for Biped Robots. IEEE-RAS International Conference on Humanoid Robots (Humanoids), Seoul, Korea, 2015.