Learning Physical Systems: Symplectification via Gauge Fixing in Dirac Structures

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Main Authors: Papatheodorou, Aristotelis, Vaidhyanathan, Pranav, Ares, Natalia, Havoutis, Ioannis
Format: Preprint
Published: 2025
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author Papatheodorou, Aristotelis
Vaidhyanathan, Pranav
Ares, Natalia
Havoutis, Ioannis
author_facet Papatheodorou, Aristotelis
Vaidhyanathan, Pranav
Ares, Natalia
Havoutis, Ioannis
contents Physics-informed deep learning has achieved remarkable progress by embedding geometric priors, such as Hamiltonian symmetries and variational principles, into neural networks, enabling structure-preserving models that extrapolate with high accuracy. However, in systems with dissipation and holonomic constraints, ubiquitous in legged locomotion and multibody robotics, the canonical symplectic form becomes degenerate, undermining the very invariants that guarantee stability and long-term prediction. In this work, we tackle this foundational limitation by introducing Presymplectification Networks (PSNs), the first framework to learn the symplectification lift via Dirac structures, restoring a non-degenerate symplectic geometry by embedding constrained systems into a higher-dimensional manifold. Our architecture combines a recurrent encoder with a flow-matching objective to learn the augmented phase-space dynamics end-to-end. We then attach a lightweight Symplectic Network (SympNet) to forecast constrained trajectories while preserving energy, momentum, and constraint satisfaction. We demonstrate our method on the dynamics of the ANYmal quadruped robot, a challenging contact-rich, multibody system. To the best of our knowledge, this is the first framework that effectively bridges the gap between constrained, dissipative mechanical systems and symplectic learning, unlocking a whole new class of geometric machine learning models, grounded in first principles yet adaptable from data.
format Preprint
id arxiv_https___arxiv_org_abs_2506_18812
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learning Physical Systems: Symplectification via Gauge Fixing in Dirac Structures
Papatheodorou, Aristotelis
Vaidhyanathan, Pranav
Ares, Natalia
Havoutis, Ioannis
Robotics
Machine Learning
Physics-informed deep learning has achieved remarkable progress by embedding geometric priors, such as Hamiltonian symmetries and variational principles, into neural networks, enabling structure-preserving models that extrapolate with high accuracy. However, in systems with dissipation and holonomic constraints, ubiquitous in legged locomotion and multibody robotics, the canonical symplectic form becomes degenerate, undermining the very invariants that guarantee stability and long-term prediction. In this work, we tackle this foundational limitation by introducing Presymplectification Networks (PSNs), the first framework to learn the symplectification lift via Dirac structures, restoring a non-degenerate symplectic geometry by embedding constrained systems into a higher-dimensional manifold. Our architecture combines a recurrent encoder with a flow-matching objective to learn the augmented phase-space dynamics end-to-end. We then attach a lightweight Symplectic Network (SympNet) to forecast constrained trajectories while preserving energy, momentum, and constraint satisfaction. We demonstrate our method on the dynamics of the ANYmal quadruped robot, a challenging contact-rich, multibody system. To the best of our knowledge, this is the first framework that effectively bridges the gap between constrained, dissipative mechanical systems and symplectic learning, unlocking a whole new class of geometric machine learning models, grounded in first principles yet adaptable from data.
title Learning Physical Systems: Symplectification via Gauge Fixing in Dirac Structures
topic Robotics
Machine Learning
url https://arxiv.org/abs/2506.18812