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Balancing and {Walking} {Using} {Full} {Dynamics} {LQR} {Control} {With} {Contact} {Constraints}


Conference Paper



Torque control algorithms which consider robot dynamics and contact constraints are important for creating dynamic behaviors for humanoids. As computational power increases, algorithms tend to also increase in complexity. However, it is not clear how much complexity is really required to create controllers which exhibit good performance. In this paper, we study the capabilities of a simple approach based on contact consistent LQR controllers designed around key poses to control various tasks on a humanoid robot. We present extensive experimental results on a hydraulic, torque controlled humanoid performing balancing and stepping tasks. This feedback control approach captures the necessary synergies between the DoFs of the robot to guarantee good control performance. We show that for the considered tasks, it is only necessary to re-linearize the dynamics of the robot at different contact configurations and that increasing the number of LQR controllers along desired trajectories does not improve performance. Our result suggest that very simple controllers can yield good performance competitive with current state of the art, but more complex, optimization-based whole-body controllers. A video of the experiments can be found at https://youtu.be/5T08CNKV1hw.

Author(s): Mason, S and Rotella, N and Schaal, S. and Righetti, L.
Book Title: 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids)
Pages: 63--68
Year: 2016
Publisher: IEEE

Department(s): Autonomous Motion, Movement Generation and Control
Bibtex Type: Conference Paper (inproceedings)

DOI: 10.1109/HUMANOIDS.2016.7803255

Address: Cancun, Mexico
URL: https://arxiv.org/abs/1701.08179


  title = {Balancing and {Walking} {Using} {Full} {Dynamics} {LQR} {Control} {With} {Contact} {Constraints}},
  author = {Mason, S and Rotella, N and Schaal, S. and Righetti, L.},
  booktitle = {2016 {IEEE}-{RAS} 16th {International} {Conference} on {Humanoid} {Robots} ({Humanoids})},
  pages = {63--68},
  publisher = {IEEE},
  address = {Cancun, Mexico},
  year = {2016},
  url = {https://arxiv.org/abs/1701.08179}