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2 results (View BibTeX file of all listed publications)

2019

Thumb xl screen shot 2019 04 18 at 5.55.23 pm
Series Elastic Behavior of Biarticular Muscle-Tendon Structure in a Robotic Leg

Ruppert, F., Badri-Spröwitz, A.

Frontiers in Neurorobotics, 64, pages: 13, 13, August 2019 (article)

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Frontiers YouTube link (url) DOI [BibTex]

2019

dlg Ruppert, F., Badri-Spröwitz, A. Series Elastic Behavior of Biarticular Muscle-Tendon Structure in a Robotic Leg Frontiers in Neurorobotics, 64, pages: 13, 13, August 2019 (article)

Frontiers YouTube link (url) DOI [BibTex]

Thumb xl screenshot 2019 08 19 at 13.54.21
Beyond Basins of Attraction: Quantifying Robustness of Natural Dynamics

Steve Heim, , Spröwitz, A.

IEEE Transactions on Robotics (T-RO) , 35(4), pages: 939-952, August 2019 (article)

Abstract
Properly designing a system to exhibit favorable natural dynamics can greatly simplify designing or learning the control policy. However, it is still unclear what constitutes favorable natural dynamics and how to quantify its effect. Most studies of simple walking and running models have focused on the basins of attraction of passive limit cycles and the notion of self-stability. We instead emphasize the importance of stepping beyond basins of attraction. In this paper, we show an approach based on viability theory to quantify robust sets in state-action space. These sets are valid for the family of all robust control policies, which allows us to quantify the robustness inherent to the natural dynamics before designing the control policy or specifying a control objective. We illustrate our formulation using spring-mass models, simple low-dimensional models of running systems. We then show an example application by optimizing robustness of a simulated planar monoped, using a gradient-free optimization scheme. Both case studies result in a nonlinear effective stiffness providing more robustness.

dlg

arXiv preprint arXiv:1806.08081 T-RO link (url) DOI Project Page [BibTex]

dlg Steve Heim, , Spröwitz, A. Beyond Basins of Attraction: Quantifying Robustness of Natural Dynamics IEEE Transactions on Robotics (T-RO) , 35(4), pages: 939-952, August 2019 (article)

arXiv preprint arXiv:1806.08081 T-RO link (url) DOI Project Page [BibTex]