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Chair for Dynamics/Mechatronics
ITM Logo

Prof. Wolfgang Seemann
Prof. Carsten Proppe
Prof. Alexander Fidlin


Karlsruher Institut für Technologie (KIT)
Kaiserstraße 10
Gebäude: 10.23, 2. OG
76131 Karlsruhe

Tel:  +49 721 608-42397
Tel:  +49 721 608-42659
Fax: +49 721 608-46070
dm-sekretariatKhs8∂itm kit edu

Quick guide Dynamics/Mechatronics
Ulrich Römer

Ulrich Römer

Research Assistant
Office Hours: 

by appointment

Room: 205.2
CS 10.23

Phone: +49 721 608-46823
Fax: +49 721 608-46070
ulrich roemerSka1∂kit edu

Karlsruher Institut für Technologie
Institut für Technische Mechanik
Teilinstitut Dynamik/Mechatronik
Postfach 6980
76049 Karlsruhe

Haus- und Lieferanschrift:
KIT-Campus Süd
Institut für Technische Mechanik
Teilinstitut Dynamik/Mechatronik
Geb. 10.23 R 205.2
Kaiserstraße 10
76131 Karlsruhe


Design of bipedal robots with optimized energy efficiency in varying environments

five link bipedal robot
mean energy consumption per distance over different climbing inclination angles
energy consumption per distance over different walking speeds

In the development of biped robots, energy efficient locomotion via walking or running is a major research priority. Due to the limited energy storage (battery), energy efficiency significantly determines the walking distance that can be covered. Energy efficiency depends not only on the controller used for stabilizing the motion, but also on the structural design and its mechanical model parameters. Hence, the purpose of this research is to develop and apply a method to systematically optimize the structure of a bipedal robot to maximize energy efficiency in different environments.

In the first step we consider an underactuated robot model which consists of five segments. Its rigid segments are additionally connected by elastic couplings such as torsion springs. Knowing that the robot’s periodic walking or running gaits can be analyzed as limit cycles of the controlled mechanical system, its resonance frequency can be adjusted to match the current step frequency by modifying the elastic couplings. A systematic approach to achieve this matching consists in the simultaneous optimization of the elastic couplings and the controlled motion. Consequently, the robot exploits the mechanical system's natural dynamics instead of wasting energy on its suppression.

Since the optimization of the parameters essentially depends on the conditions of the environment and the gait, the focus is on how the adaptation of the robot to the current operating state can be realized. Unlike the motion, which can be continuously updated by the controller based on the measured state variables, the elastic couplings need to be optimized to achieve the best characteristics by using "compliant smart mechanics" (COSM). Between the stance and swing phases of the robot’s legs, and especially during switching processes of the movement, an optimal (force-displacement and/or force-velocity) characteristic of COSM leads to an overall high energy efficiency for a wide range of walking scenarios.

This project is being carried out jointly by two research groups: The Compliant Systems Group (FG NSYS) from the Ilmenau University of Technology (TU Ilmenau) and the Institute of Engineering Mechanics (ITM) from the Karlsruhe Institute of Technology (KIT). While the team at TU Ilmenau investigates the compliant mechanical systems and their design and implementation, the team at KIT simulates and optimizes bipedal robots with those COSM mechanisms in different environments. It is financially supported by the German Research Foundation (DFG), grant FI 1761/4-1 | ZE 714/16-1.


Project partner: Prof. L. Zentner, M. Zirkel.

Contact: Prof. A. Fidlin, Dr. U. Römer, Y. Luo


Über den Einfluss der Fußgeometrie auf die Energieeffizienz beim zweibeinigen Gehen. Dissertation.
Römer, U. J.
2019. KIT Scientific Publishing, Karlsruhe. doi:10.5445/KSP/1000089994

Publications in Journals and Conference Proceedings

The normal parameterization and its application to collision detection.
Römer, U. J.; Fidlin, A.; Seemann, W.
2020. Mechanism and machine theory, 151, Art.-Nr.: 103906. doi:10.1016/j.mechmachtheory.2020.103906
A Brief Survey on Non-standard Constraints: Simulation and Optimal Control.
Kern, D.; Römer, U. J.
2019. Proceedings of 8th GACM Colloquium on Computational Mechanics, 211–214, kassel university press GmbH, Kassel
Simultaneous optimization of gait and design parameters for bipedal robots.
Römer, U. J.; Kuhs, C.; Krause, M. J.; Fidlin, A.
2016. Proceedings of the 2016 IEEE International Conference on Robotics and Automation (ICRA), Stockholm, Sweden 16-21 May 2016, 1374–1381, IEEE, Piscataway (NJ). doi:10.1109/ICRA.2016.7487271
Investigation of optimal bipedal walking gaits subject to different energy-based objective functions.
Römer, U.; Fidlin, A.; Seemann, W.
2015. Proceedings in applied mathematics and mechanics, 15 (1), 69–70. doi:10.1002/pamm.201510025
Energy-optimized bipedal running of a simple humanoid robot.
Römer, U.; Fidlin, A.
2014. Proceedings in applied mathematics and mechanics, 14 (1), 81–82. doi:10.1002/pamm.201410028
Transition from walking to running of a bipedal robot to optimize energy efficiency.
Römer, U.; Bauer, F.; Fidlin, A.
2014. 17th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2014, Poznan, Poland; 21 - 23 July, 2014, 409–416, World Scientific, Singapore. doi:10.1142/9789814623353_0048

Talks at Conferences and Colloquia

Kontaktdetektion zwischen konvexen Objekten auf Basis der Normalenparameterisierung.
Römer, U. J.; Seemann, W.; Fidlin, A.
2020, Februar 27. 6. IFToMM D-A-CH Konferenz (2020), Lienz, Österreich, 27.–28. Februar 2020. doi:10.17185/duepublico/71212
Two-dimensional contact problems revisited – explicit analytical solutions for contact detection with straight and circular counterparts.
Römer, U. J.; Fidlin, A.; Seemann, W.
2018. 89. Jahrestagung der Gesellschaft für angewandte Mathematik und Mechanik (GAMM 2018), München, Deutschland, 19.–23. März 2018
Dance-like motions in optimal walking.
Römer, U. J.; Fidlin, A.
2017. 9th European Nonlinear Dynamics Conference (ENOC 2017), Budapest, Ungarn, 25.–30. Juni 2017 Volltext Volltext der Publikation als PDF-Dokument
Design and optimization of hybrid zero dynamics for a bipedal walking robot with series elastic actuators.
Römer, U. J.; Fidlin, A.; Seemann, W.
2016. 87. Jahrestagung der Gesellschaft für angewandte Mathematik und Mechanik (GAMM 2016), Braunschweig, Deutschland, 7.–11. März 2016
A novel analytical foot rollover model for planar walking.
Römer, U. J.; Fidlin, A.
2016. Dynamic Walking (2016), Holly, MI, USA, 4.–7. Juni 2016 Volltext Volltext der Publikation als PDF-Dokument
Energy optimization of bipedal walking through parallel springs.
Römer, U.; Bauer, F.; Seemann, W.; Fidlin, A.
2014, Mai 14. 4th French-German-Japanese Conference on Humanoid and Legged Robots (2014), Heidelberg, Deutschland, 12.–14. Mai 2014


Offered theses
Title Type Date
Thesis (B.Sc. or M.Sc.) as of now
Thesis (B.Sc. or M.Sc.) as of the end of COVID-19 restrictions

Completed theses
Title Type Graduand

Amira Khelifi

Master thesis

Alexander Michael Dyck

Master thesis

Yonzhou Zhang

Bachelor thesis

Daniel Debertin

Bachelor thesis

Franziska Krebs

Master thesis

Jimmy Alberto Aramendiz Fuentes

Bachelor thesis

Jan-Hendrik Witt

Bachelor thesis

Shreyas Vivek Joshi

Master thesis

Simon Lüdke

Master thesis

Cornelius Kuhs 

Bachelor thesis

Timo Fetzer 

Bachelor thesis

Jan Wachter 

Bachelor thesis

Sonja Marahrens 

Bachelor thesis

Simeon Braun

Master thesis

Philipp König

Bachelor thesis

Christian Pihuave


Most of the courses offered by the Institute of Engineering Mechanics are held in German. For more information please follow the individual links.

Given courses
Semester Title
SS 20
WS 19/20
SS 19
SS 19
SS 18
WS 17/18
WS 17/18
WS 16/17
SS 16
SS 16
WS 15/16
SS 15
SS 15
WS 14/15
SS 14
SS 14
WS 13/14
WS 13/14
SS 13