Using Torque Redundancy to Optimize Contact Forces in Legged Robots

  • Ludovic RighettiEmail author
  • Jonas Buchli
  • Michael Mistry
  • Mrinal Kalakrishnan
  • Stefan Schaal
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 57)


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.


Contact Force Tangential Force Ground Reaction Force Humanoid Robot Constraint Force 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Ludovic Righetti
    • 1
    Email author
  • Jonas Buchli
    • 3
  • Michael Mistry
    • 4
  • Mrinal Kalakrishnan
    • 1
  • Stefan Schaal
    • 2
  1. 1.University of Southern CaliforniaLos AngelesUSA
  2. 2.Max-Planck Institute for Intelligent SystemsTübingenGermany
  3. 3.Italian Institute of TechnologyGenoaItaly
  4. 4.University of BirminghamBirminghamUK

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