Sim-to-Real of Soft Robots with Learned Residual Physics

Fuente: arXiv
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Autori principali: Gao, Junpeng, Michelis, Mike Yan, Spielberg, Andrew, Katzschmann, Robert K.
Natura: Preprint
Pubblicazione: 2024
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author Gao, Junpeng
Michelis, Mike Yan
Spielberg, Andrew
Katzschmann, Robert K.
author_facet Gao, Junpeng
Michelis, Mike Yan
Spielberg, Andrew
Katzschmann, Robert K.
contents Accurately modeling soft robots in simulation is computationally expensive and commonly falls short of representing the real world. This well-known discrepancy, known as the sim-to-real gap, can have several causes, such as coarsely approximated geometry and material models, manufacturing defects, viscoelasticity and plasticity, and hysteresis effects. Residual physics networks learn from real-world data to augment a discrepant model and bring it closer to reality. Here, we present a residual physics method for modeling soft robots with large degrees of freedom. We train neural networks to learn a residual term -- the modeling error between simulated and physical systems. Concretely, the residual term is a force applied on the whole simulated mesh, while real position data is collected with only sparse motion markers. The physical prior of the analytical simulation provides a starting point for the residual network, and the combined model is more informed than if physics were learned tabula rasa. We demonstrate our method on 1) a silicone elastomeric beam and 2) a soft pneumatic arm with hard-to-model, anisotropic fiber reinforcements. Our method outperforms traditional system identification up to 60%. We show that residual physics need not be limited to low degrees of freedom but can effectively bridge the sim-to-real gap for high dimensional systems.
format Preprint
id arxiv_https___arxiv_org_abs_2402_01086
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Sim-to-Real of Soft Robots with Learned Residual Physics
Gao, Junpeng
Michelis, Mike Yan
Spielberg, Andrew
Katzschmann, Robert K.
Robotics
Accurately modeling soft robots in simulation is computationally expensive and commonly falls short of representing the real world. This well-known discrepancy, known as the sim-to-real gap, can have several causes, such as coarsely approximated geometry and material models, manufacturing defects, viscoelasticity and plasticity, and hysteresis effects. Residual physics networks learn from real-world data to augment a discrepant model and bring it closer to reality. Here, we present a residual physics method for modeling soft robots with large degrees of freedom. We train neural networks to learn a residual term -- the modeling error between simulated and physical systems. Concretely, the residual term is a force applied on the whole simulated mesh, while real position data is collected with only sparse motion markers. The physical prior of the analytical simulation provides a starting point for the residual network, and the combined model is more informed than if physics were learned tabula rasa. We demonstrate our method on 1) a silicone elastomeric beam and 2) a soft pneumatic arm with hard-to-model, anisotropic fiber reinforcements. Our method outperforms traditional system identification up to 60%. We show that residual physics need not be limited to low degrees of freedom but can effectively bridge the sim-to-real gap for high dimensional systems.
title Sim-to-Real of Soft Robots with Learned Residual Physics
topic Robotics
url https://arxiv.org/abs/2402.01086