A Physically Consistent Stiffness Formulation for Contact-Rich Manipulation

Fuente: arXiv
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Hauptverfasser: Lachner, Johannes, Nah, Moses C., Hogan, Neville
Format: Preprint
Veröffentlicht: 2025
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author Lachner, Johannes
Nah, Moses C.
Hogan, Neville
author_facet Lachner, Johannes
Nah, Moses C.
Hogan, Neville
contents Ensuring symmetric stiffness in impedance-controlled robots is crucial for physically meaningful and stable interaction in contact-rich manipulation. Conventional approaches neglect the change of basis vectors in curved spaces, leading to an asymmetric joint-space stiffness matrix that violates passivity and conservation principles. In this work, we derive a physically consistent, symmetric joint-space stiffness formulation directly from the task-space stiffness matrix by explicitly incorporating Christoffel symbols. This correction resolves long-standing inconsistencies in stiffness modeling, ensuring energy conservation and stability. We validate our approach experimentally on a robotic system, demonstrating that omitting these correction terms results in significant asymmetric stiffness errors. Our findings bridge theoretical insights with practical control applications, offering a robust framework for stable and interpretable robotic interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06802
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Physically Consistent Stiffness Formulation for Contact-Rich Manipulation
Lachner, Johannes
Nah, Moses C.
Hogan, Neville
Robotics
Ensuring symmetric stiffness in impedance-controlled robots is crucial for physically meaningful and stable interaction in contact-rich manipulation. Conventional approaches neglect the change of basis vectors in curved spaces, leading to an asymmetric joint-space stiffness matrix that violates passivity and conservation principles. In this work, we derive a physically consistent, symmetric joint-space stiffness formulation directly from the task-space stiffness matrix by explicitly incorporating Christoffel symbols. This correction resolves long-standing inconsistencies in stiffness modeling, ensuring energy conservation and stability. We validate our approach experimentally on a robotic system, demonstrating that omitting these correction terms results in significant asymmetric stiffness errors. Our findings bridge theoretical insights with practical control applications, offering a robust framework for stable and interpretable robotic interactions.
title A Physically Consistent Stiffness Formulation for Contact-Rich Manipulation
topic Robotics
url https://arxiv.org/abs/2503.06802