Abstract | ||
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Recent experiments have shown that human joints can maintain a constant damping ratio across a wide range of external loads. This behavior can be explained by the use of a "complex stiffness" frequency-domain model approximating the impedance of the human joint. However, for a robot to replicate this naturally beneficial human behavior would require a time-domain model of this nonlinear joint impedance. This paper demonstrates that there exists a nonlinear time-domain model (originally from the structural mechanics community) that has a frequency-domain "describing function" that matches the complex stiffness model observed in humans. We provide an extension of this nonlinear time-domain model that removes the need to implement hard-switching control input. In addition, we demonstrate that this proportional-and-hysteretic-damping controller has inertia-invariant overshoot and therefore offers an advantage over the more common proportional-derivative control approach. Implementing the proposed proportional-and-hysteretic-damping control in a single-joint test-robot, we demonstrate for the first time that the desired frequency domain behavior can be reproduced in practice. |
Year | DOI | Venue |
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2021 | 10.23919/ACC50511.2021.9482845 | 2021 AMERICAN CONTROL CONFERENCE (ACC) |
DocType | ISSN | Citations |
Conference | 0743-1619 | 0 |
PageRank | References | Authors |
0.34 | 0 | 4 |
Name | Order | Citations | PageRank |
---|---|---|---|
Nicolas Brissonneau | 1 | 0 | 0.34 |
Binghan He | 2 | 1 | 1.40 |
C. Gray | 3 | 3 | 2.87 |
Luis Sentis | 4 | 0 | 0.68 |