Humanoid Robot LOLA

At the Chair of Applied Mechanics biped walking machines have been developed for many years. Our current research platform "LOLA" is an electrically actuated humanoid with 24 distributed joints, 60 kilograms total weight and 180cm height. The focus of our research lies on the dynamics, real-time motion planning and control as well as the design of such systems. Please check out our YouTube channel for recent videos.


System Overview: Hardware

The kinematic structure resembles 24 electrically actuated joints, which are driven by brushless DC motors. Most of them integrate high ratio gearings as well as incremetal and absolute encoders for position sensing. Both feet feature a custom six-axis force-torque sensor and four binary contact switches each, to measure ground reaction forces and contact states. In the upper body an accelerometer and ring laser gyroscope help during inertial stabilization. The head is equipped with a depth sensor which provides a three dimensional representation of the environment as point cloud.


System Overview: Software

Our hierarchical control framework combines modules for environment perception, navigation and motion planning as well as local stabilization and inverse kinematics. Since our focus lies on autonomy, all algorithms run on board and in real-time. The only exception is an operator PC which allows the user to send high level commands, such as walking direction or goal position, to the robot. Furthermore a sophisticated simulation, considering full multi-body dynamics, electro-dynamics and low level drive controllers, is used to test new methods without putting our hardware at risk. Over 80 percent of the source code is written in highly efficient C++ for maximum runtime performance.

Publicly Available Software Libraries

  • broccoli - Beautiful Robot C++ Code Library
  • lolaCAT - An EtherCAT-Based Real-Time Control System Architecture for Robotic Applications

Current Projects

Adaptive Walking through Multi-Contact Stabilization (DFG #407378162)

The main goal of this project is to further reduce the gap between human and robot locomotion. For this purpose, methods are developed, which allow the robot to adapt its behavior dynamically to its environment. This includes on the one hand the use of multiple contacts during fast locomotion, i.e. additional hand support for stabilization, as well as the improvement of kinematic capabilities through clever control of the degrees of freedom and partial surface contacts on the other hand. The main focus lies on fast locomotion in previously unknown environments while simultaneously maintaining stability and robustness. The core research topics to achieve this goal are

  • Perception, Environment Modelling, Localization
  • Navigation and Motion Planning
  • Stabilization and Multi-Contact Control

This project is a cooperation with the Chair for Computer Aided Medical Procedures & Augmented Reality.

Perception, Environment Modelling, Localization

(Visual) perception describes the task of sensing the environment without physical interaction, i.e. without mechanical contacts. The related software module incrementally generates an environment model with semantic labels while keeping track of the current location of the robot. The built map then can be used for navigation and motion planning where the semantic labelling gives hints on potential support areas and obstables.

Navigation and Motion Planning

The environment model is used to plan a feasible path preferring routes close to possible support candidates such as walls or tables. The resulting sequence of discrete robot poses is then connected by smooth trajectories representing a dynamically balanced gait. Special focus lies on stability in multi-contact situations and optimization techniques to maximize kinematic capabilities.

Stabilization and Multi-Contact Control

The use of multiple contacts while running requires a quick adaptation of the system in case of disturbances or deviations between reality and planning. A corresponding stabilization and force control of the contacts through the use of sensor information allows to compensate unexpected contact characteristics as well as unplanned or delayed contacts.

Test Scenario

The test scenario depicted below is used to evaluate the investigated methods and algorithms. The key features are support against handrails, walls and tables, generic collision avoidance with static and dynamic obstacles as well as stepping over large obstacles and exploiting kinematics during climbing stairs and walking on ramps.

Fast Biped Walking on Uneven Terrain

The projects main goal is to increase the robustness of biped walking on uneven terrain and floors with different mechanical properties. We evaluate the performance of the developed methods by walking terrain-blind over a set of unknown obstacles --- i.e. no vision-based information is required for the approaches to work. The focus is on the fast (≥ 0.5 m/s) traversal of such environments.

Contact Force Control

The robustness to uncertain and undetected terrains is achieved by control of the ground reaction forces of the biped robot. Our control scheme includes reactive feedforward components for early contacts of the feet, as well as feedback control of the sensed contact wrenches. The force control approach considers sensor-based geometric contact information of the contact to the ground as well as the dynamics of the center of mass.

More information is available in our publication.

Tactile Sensing

Currently, the contact state and estimated contact geometry (pressure distribution) between the foot and the ground is sensed via four discrete contact switches on each foot. To get a more accurate information on the contact geometry in uneven terrain, a lightweight and flexible tactile sensor has been developed. By integration of the sensor to the robot's feet, we expect increased performance of our existing force-control approaches in uneven terrain.

For more information, please see our publication: 
A Flexible and Low-Cost Tactile Sensor for Robotic Applications

Test Scenario

The approaches are validated in a complex scenario with uneven, irregularly protruded surfaces. All tests are conducted without any (vision-based) information on the terrain. This means the motion plan is generated for flat terrain and only the force-control may adapt the trajectories based on the sensor data.


Past Projects

For information on past projects related to our humanoid robots LOLA and JOHNNIE, please follow this link.


Student Projects

If you are interested in writing a student thesis (BA/SA/IDP/MA) on a topic related to the humanoid LOLA or you want to contribute to the project as a student assistant (HiWi), please contact one of the current members of the research group (see list below).

Note: In case you are interested in a topic related to computer vision, please contact our project partners

from the Chair for Computer Aided Medical Procedures & Augmented Reality.


Research Group Humanoid Robotics

Current Members

Former Members

  • Dr.-Ing. Sebastian Lohmeier
  • Dr.-Ing. Mathias Bachmayer
  • Dr.-Ing. Valerio Favot
  • Dr.-Ing. Markus Schwienbacher
  • Dr.-Ing. Alexander Ewald
  • Dr.-Ing. Thomas Buschmann
  • Dr.-Ing. Robert Wittmann
  • Dr.-Ing. Arne-Christoph Hildebrandt
  • Dr.-Ing. Daniel Wahrmann

Project Partners

Chair for Computer Aided Medical Procedures & Augmented Reality, TUM
Movement and Exercise Science, Institute of Sports Science, Friedrich-Schiller-Universität Jena

Acknowledgments

This project is funded by the German Research Foundation (Deutsche Forschungsgemeinschaft - DFG).

We thank the following companies for their kind support:

Publications

2019

  • Hildebrandt, Arne-Christoph; Wittmann, Robert; Sygulla, Felix; Wahrmann, Daniel; Rixen, Daniel; Buschmann, Thomas: Versatile and Robust Bipedal Walking in Unknown Environments. Autonomous Robots, 2019 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Sygulla, Felix; Rixen, Daniel: A Force Control Scheme for Biped Robots to Walk over Uneven Terrain Including Partial Footholds. Preprint - submitted for publication, 2019 more… BibTeX Full text (mediaTUM)
  • Wahrmann, Daniel; Hildebrandt, Arne-Christoph; Bates, Tamas; Wittmann, Robert; Sygulla, Felix; Seiwald, Philipp; Rixen, Daniel: Vision-Based 3D Modeling of Unknown Dynamic Environments for Real-Time Humanoid Navigation. International Journal of Humanoid Robotics, 2019 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Wahrmann, Daniel; Hildebrandt, Arne-Christoph; Schuetz, Christoph; Wittmann, Robert; Rixen, Daniel: An Autonomous and Flexible Robotic Framework for Logistics Applications. Journal of Intelligent {&} Robotic Systems 93 (3), 2019, 419-431 more… BibTeX Full text ( DOI ) Full text (mediaTUM)

2018

  • Hildebrandt, Arne-Christoph; Schwerd, Simon; Wittmann, Robert; Wahrmann, Daniel; Sygulla, Felix; Seiwald, Philipp; Rixen, Daniel; Buschmann, Thomas: Kinematic Optimization for Bipedal Robots. Autonomous Robots, 2018 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Hildebrandt, Arne-Christoph; Ritt, Konstantin; Wahrmann, Daniel; Wittmann, Robert; Sygulla, Felix; Seiwald, Philipp; Rixen, Daniel; Buschmann, Thomas: Torso height optimization for bipedal locomotion. International Journal of Advanced Robotic Systems 15 (5), 2018, 172988141880444 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Seiwald, Philipp; Leyerer, Anian; Sygulla, Felix; Rixen, Daniel: Parameter Optimization of a Reduced Model for Multi-Contact Locomotion of Humanoid Robots. PAMM 18 (1), 2018, e201800138 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Sygulla, Felix; Wittmann, Robert; Seiwald, Philipp; Berninger, Tobias; Hildebrandt, Arne-Christoph; Wahrmann, Daniel; Rixen, Daniel: An EtherCAT-Based Real-Time Control System Architecture for Humanoid Robots. IEEE International Conference on Automation Science and Engineering (CASE), 2018 more… BibTeX Full text (mediaTUM)
  • Wahrmann, Daniel; Wu, Yizhe; Sygulla, Felix; Hildebrandt, Arne-Christoph; Wittmann, Robert; Seiwald, Philipp; Rixen, Daniel: Time-variable, event-based walking control for biped robots. International Journal of Advanced Robotic Systems 15 (2), 2018 more… BibTeX Full text ( DOI ) Full text (mediaTUM)

2017

  • Hildebrandt, Arne-Christoph; Klischat, Moritz; Wahrmann, Daniel; Wittmann, Robert; Sygulla, Felix; Seiwald, Philipp; Rixen, Daniel; Buschmann, Thomas: Real-Time Path Planning in Unknown Environments for Bipedal Robots. IEEE Robotics and Automation Letters 2 (4), 2017, 1856--1863 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Sygulla, Felix; Ellensohn, Felix; Hildebrandt, Arne-Christoph; Wahrmann, Daniel; Rixen, Daniel: A Flexible and Low-Cost Tactile Sensor for Robotic Applications. IEEE International Conference on Advanced Intelligent Mechatronics (AIM), 2017 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Sygulla, Felix; Wittmann, Robert; Seiwald, Philipp; Hildebrandt, Arne-Christoph; Wahrmann, Daniel; Rixen, Daniel: Hybrid Position/Force Control for Biped Robot Stabilization with Integrated Center of Mass Dynamics. IEEE RAS International Conference on Humanoid Robots, 2017 more… BibTeX Full text (mediaTUM)
  • Wahrmann, Daniel; Knopp, Tilman; Wittmann, Robert; Hildebrandt, Arne-Christoph; Sygulla, Felix; Seiwald, Philipp; Rixen, Daniel; Buschmann, Thomas: Modifying the Estimated Ground Height to Mitigate Error Effects on Bipedal Robot Walking. IEEE International Conference on Advanced Intelligent Mechatronics (AIM), IEEE, 2017 more… BibTeX Full text ( DOI ) Full text (mediaTUM)

2016

  • Hildebrandt, Arne-Christoph; Wahrmann, Daniel; Wittmann, Robert; v. Deimling, Constantin; Rixen, Daniel: Autonomous Robotics: Application on Legged and Agricultural Robots. DGR-Days, Deutsche Gesellschaft für Robotik, 2016 more… BibTeX Full text (mediaTUM)
  • Hildebrandt, Arne-Christoph; Demmeler, Manuel; Wittmann, Robert; Wahrmann, Daniel; Sygulla, Felix; Rixen, Daniel; Buschmann, Thomas: Real-Time Predictive Kinematic Evaluation and Optimization for Biped Robots. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2016 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Wahrmann, Daniel; Hildebrandt, Arne-Christoph; Wittmann, Robert; Sygulla, Felix; Rixen, Daniel; Buschmann, Thomas: Fast Object Approximation for Real-Time 3D Obstacle Avoidance with Biped Robots. IEEE International Conference on Advanced Intelligent Mechatronics (AIM), IEEE, 2016 more… BibTeX Full text (mediaTUM)
  • Wahrmann, Daniel; Hildebrandt, Arne-Christoph; Wittmann, Robert; Sygulla, Felix; Rixen, Daniel; Buschmann, Thomas: 3D-Modellierung dynamischer Umgebungen für Echt-Zeit-Navigation autonomer zweibeiniger Roboter. VDI-Zukunftskonferenz Humanoide Roboter 2016, VDI, 2016 more… BibTeX Full text (mediaTUM)
  • Wittmann, Robert; Hildebrandt, Arne-christoph; Wahrmann, Daniel; Sygulla, Felix; Rixen, Daniel; Buschmann, Thomas: Model-Based Predictive Bipedal Walking Stabilization. IEEE-RAS International Conference on Humanoid Robots, 2016 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Wittmann, Robert; Rixen, Daniel: A Prediction Model for State Observation and Model Predictive Control of Biped Robots. Proc. Appl. Math. Mech., Wiley-Blackwell, 2016 more… BibTeX Full text ( DOI ) Full text (mediaTUM)

2015

  • 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 more… BibTeX Full text (mediaTUM)
  • Wittmann, Robert; Hildebrandt, Arne-Christoph; Wahrmann, Daniel; Buschmann, Thomas; Rixen, Daniel: State Estimation for Biped Robots Using Multibody Dynamics. IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, 2015 more… BibTeX Full text (mediaTUM)
  • 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, 2015 more… BibTeX Full text (mediaTUM)

2014

  • Hildebrandt, Arne-Christoph; Wittmann, Robert; Wahrmann, Daniel; Ewald, Alexander; Buschmann, Thomas: Real-Time 3D Collision Avoidance for Biped Robots. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2014 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Wittmann, Robert; Hildebrandt, Arne-Christoph; Ewald, Alexander; Buschmann, Thomas: An Estimation Model for Footstep Modifications of Biped Robots. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2014 more… BibTeX Full text ( DOI ) Full text (mediaTUM)

2013

2012

  • Buschmann, T. and Schwienbacher, M. and Favot, V. and Ewald, A. and Ulbrich, H.: Dynamics and Control of the Biped Robot Lola. Multibody System Dynamics, Robotics and Control., 2012 more… BibTeX Full text (mediaTUM)
  • Buschmann, T. and Schwienbacher, M. and Favot, V. and Ewald, A. and Ulbrich, H.: The Biped Walking Robot Lola -- Hardware Design and Walking Control --. Journal of the Robotics Society of Japan 30, 2012 more… BibTeX Full text (mediaTUM)
  • Buschmann, T.; Ewald, A.; Ulbrich, H.; Büschges, A.: Event-Based Walking Control - From Neurobiology to Biped Robots. IROS, 2012 more… BibTeX Full text (mediaTUM)
  • Buschmann, T.; Schwienbacher, M.; Favot, V.; Ewald, A.; Ulbrich, H.: Laufregelung redundanter humanoider Roboter -- ein modellbasierter Ansatz. at -- Automatisierungstechnik, 2012 more… BibTeX Full text ( DOI ) Full text (mediaTUM)
  • Buschmann, T.; Schwienbacher, M.; Favot, V.; Ewald, A.; Ulbrich, H.: The Biped Walking Robot Lola -- Hardware Design and Walking Control --. Journal of the Robotics Society of Japan 30 (4), 2012 more… BibTeX Full text (mediaTUM)
  • Buschmann, T.; Wittmann, R.; Schwienbacher, M.; Ulbrich, H.: A Method for Real-Time Kineto-Dynamic Trajectory Generation. HUMANOIDS, 2012 more… BibTeX Full text (mediaTUM)
  • Ewald, A.; Mayet, J.; Buschmann, T.; Ulbrich, H.: Generating Smooth Trajectories Free from Overshoot for Humanoid Robot Walking Pattern Replanning. Autonomous Mobile Systems (AMS), 2012 more… BibTeX Full text (mediaTUM)
  • Favot, V.; Buschmann, T.; Schwienbacher, M.; Ewald, A.; Ulbrich, H.: The Sensor-Controller Network of the Humanoid Robot LOLA. Humanoids, 2012 more… BibTeX Full text (mediaTUM)
  • Markus Schwienbacher AND Thomas Buschmann AND Heinz Ulbrich: Vertical Angular Momemtum Minimization for Biped Robots with Kinematically Redundant Joints. Proceedings of the 23rd International Congress of Theoretical and Applied Mechanics (ICTAM), 2012 more… BibTeX Full text (mediaTUM)

2011

  • Buschmann, T. and Favot, V. Lohmeier, S. and Schwienbacher, M. and Ulbrich, H.: Experiments in Fast Biped Walking. Mechatronics, 2011. ICM 2011. IEEE International Conference on, 2011 more… BibTeX Full text (mediaTUM)
  • Schwienbacher, M. and Buschmann, T. and Lohmeier, S. and Favot, V. and Ulbrich, H.: Self-Collision Avoidance and Angular Momentum Compensation for a Biped Humanoid Robot. Proceedings of the International Conference on Robotics and Automation (ICRA), 2011 more… BibTeX Full text ( DOI ) Full text (mediaTUM)

2010

  • Buschmann, T. and Lohmeier, S. and Schwienbacher, M. and Favot, V. and Ulbrich, H. and Hundelshausen, F. v. and Rohe, G. and Wuenche, H.-J.: Walking in Unknown Environments - a Step Towards More Autonomy. Proc IEEE-RAS Int Conference on Humanoid Robotics (Humanoids), 2010 more… BibTeX Full text (mediaTUM)
  • Buschmann, T. and Lohmeier, S. and Ulbrich, H.: Entwurf und Regelung des Humanoiden Laufroboters Lola. at - Automatisierungstechnik 11, 2010, 613-621 more… BibTeX Full text (mediaTUM)

2009

  • Buschmann, T. and Lohmeier, S. and Ulbrich, H.: Humanoid Robot Lola: Design and Walking Control. Journal of physiology, Paris 7, 2009, 141-148 more… BibTeX Full text (mediaTUM)
  • Buschmann, T. and Lohmeier, S. and Ulbrich, H.: Biped Walking Control Based on Hybrid Position/Force Control. Proc. IROS 2009, IEEE/RSJ Int. Conf. Intelligent Robots and Systems, 2009 more… BibTeX Full text (mediaTUM)
  • Schwienbacher, M. and Favot, V. and Buschmann, T. and Lohmeier, S. and Ulbrich, H.: Walking Humanoid Robot Lola - An overview of Hard- and Software. AMS 2009 - Autonome Mobile Systeme 2009 (Informatik Aktuell), 2009 more… BibTeX Full text (mediaTUM)

2008

  • Buschmann, T. and Lohmeier, S. and Ulbrich, H. and Pfeiffer, F.: Regelung des humanoiden Laufroboters LOLA. VDI-Berichte Nr. 2012: Robotik 2008, 2008 more… BibTeX Full text (mediaTUM)

2007

  • Buschmann, T. and Lohmeier, S. and Bachmayer, M. and Ulbrich, H. and Pfeiffer, F.: A Collocation Method for Real-Time Walking Pattern Generation. Proc IEEE-RAS Int Conference on Humanoid Robotics (Humanoids), 2007 more… BibTeX Full text (mediaTUM)
  • Buschmann, T. and Lohmeier, S. and Kuehnlenz, K. and Buss, M. and Ulbrich, H. and Pfeiffer, F.: LOLA - a Performance Enhanced Humanoid Robot. it - Information Technology 49, 2007, 218-223 more… BibTeX Full text (mediaTUM)
  • Ulbrich, H. and Buschmann, T. and Lohmeier, S.: Design and Realization of Humanoid Robots at AM-TUM. Proc. of the XII Intl. Symposium on Dynamic Problems of Mechanics (DINAME 2007), 2007 more… BibTeX Full text (mediaTUM)

2006

  • Buschmann, T. and Lohmeier, S. and Ulbrich, H. and Pfeiffer, F.: Modeling and Simulation of a Biped Robot. Proc of the 2006 IEEE Intl Conf of Intelligent Robots and Systems, 2006 more… BibTeX Full text (mediaTUM)
  • Ulbrich, H. and Buschmann, T. and Lohmeier, S.: Development of the Humanoid Robot LOLA. Applied Mechanics and Materials 5-6, 2006, 529-539 more… BibTeX Full text (mediaTUM)

2005

  • Buschmann, T. and Lohmeier, S. and Ulbrich, H. and Pfeiffer, F.: Optimization Based Gait Pattern Generation for a Biped Robot. Proc IEEE-RAS Int Conference on Humanoid Robotics (Humanoids), 2005 more… BibTeX Full text (mediaTUM)