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Using Torque Redundancy to Optimize Contact Forces in Legged Robots


Book Chapter



The development of legged robots for complex environments requires controllers that guarantee both high tracking performance and compliance with the environment. More specifically the control of contact interaction with the environment is of crucial importance to ensure stable, robust and safe motions. In the following, we present an inverse dynamics controller that exploits torque redundancy to directly and explicitly minimize any combination of linear and quadratic costs in the contact constraints and in the commands. Such a result is particularly relevant for legged robots as it allows to use torque redundancy to directly optimize contact interactions. For example, given a desired locomotion behavior, it can guarantee the minimization of contact forces to reduce slipping on difficult terrains while ensuring high tracking performance of the desired motion. The proposed controller is very simple and computationally efficient, and most importantly it can greatly improve the performance of legged locomotion on difficult terrains as can be seen in the experimental results.

Author(s): Righetti, L. and Buchli, J. and Mistry, M. and Kalakrishnan, M and Schaal, S.
Book Title: Redundancy in Robot Manipulators and Multi-Robot Systems
Volume: 57
Pages: 35--51
Year: 2013
Series: Lecture {Notes} in {Electrical} {Engineering}
Publisher: Springer Berlin Heidelberg

Department(s): Autonomous Motion, Movement Generation and Control
Bibtex Type: Book Chapter (incollection)

URL: https://link.springer.com/chapter/10.1007/978-3-642-33971-4_3


  title = {Using {Torque} {Redundancy} to {Optimize} {Contact} {Forces} in {Legged} {Robots}},
  author = {Righetti, L. and Buchli, J. and Mistry, M. and Kalakrishnan, M and Schaal, S.},
  booktitle = {Redundancy in {Robot} {Manipulators} and {Multi}-{Robot} {Systems}},
  volume = {57},
  pages = {35--51},
  series = {Lecture {Notes} in {Electrical} {Engineering}},
  publisher = {Springer Berlin Heidelberg},
  year = {2013},
  url = {https://link.springer.com/chapter/10.1007/978-3-642-33971-4_3}