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Balancing experiments on a torque-controlled humanoid with hierarchical inverse dynamics


Conference Paper



Recently several hierarchical inverse dynamicscontrollers based on cascades of quadratic programs havebeen proposed for application on torque controlled robots.They have important theoretical benefits but have never beenimplemented on a torque controlled robot where model inaccuraciesand real-time computation requirements can beproblematic. In this contribution we present an experimentalevaluation of these algorithms in the context of balance controlfor a humanoid robot. The presented experiments demonstratethe applicability of the approach under real robot conditions(i.e. model uncertainty, estimation errors, etc). We propose asimplification of the optimization problem that allows us todecrease computation time enough to implement it in a fasttorque control loop. We implement a momentum-based balancecontroller which shows robust performance in face of unknowndisturbances, even when the robot is standing on only onefoot. In a second experiment, a tracking task is evaluatedto demonstrate the performance of the controller with morecomplicated hierarchies. Our results show that hierarchicalinverse dynamics controllers can be used for feedback controlof humanoid robots and that momentum-based balance controlcan be efficiently implemented on a real robot.

Author(s): Alexander Herzog and Ludovic Righetti and Felix Grimminger and Peter Pastor and Stefan Schaal
Book Title: Proceedings of the IEEE International Conference on Intelligent Robotics Systems
Year: 2014
Month: September

Department(s): Autonomous Motion, Movement Generation and Control
Research Project(s): Model-based Control of Floating-based Robots
Bibtex Type: Conference Paper (conference)

Address: Chicago, IL
DOI: 10.1109/IROS.2014.6942678

Links: Video
Attachments: pdf


  title = {Balancing experiments on a torque-controlled humanoid with hierarchical inverse dynamics},
  author = {Herzog, Alexander and Righetti, Ludovic and Grimminger, Felix and Pastor, Peter and Schaal, Stefan},
  booktitle = {Proceedings of the IEEE International Conference on Intelligent Robotics Systems},
  address = {Chicago, IL},
  month = sep,
  year = {2014},
  month_numeric = {9}