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Contact-Constrained Lower-Limb Joint-Offset Calibration for Humanoid Robots — arXiv:2609.02306

Source: arXiv (en)
Original: https://arxiv.org/abs/2609.02306
License (as archived): CC0-1.0
Archived: 2026-10-17T05:51:14.472Z
SHA-256 of the archived text: 1cc0b91ea61920113b8608b40005461e06d338f0aee21e812e2fb81d03b07cb2
Stable URL of this page: https://metraipolis.com/documento/dc_aef047e6b8ee

How to cite

Contact-Constrained Lower-Limb Joint-Offset Calibration for Humanoid Robots — arXiv:2609.02306 — arXiv (en), https://arxiv.org/abs/2609.02306 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_aef047e6b8ee (Metraipolis archive dc_aef047e6b8ee, sha256 1cc0b91ea61920113b8608b40005461e06d338f0aee21e812e2fb81d03b07cb2)

BibTeX

@misc{dcaef047e6b8ee,
  title = {Contact-Constrained Lower-Limb Joint-Offset Calibration for Humanoid Robots — arXiv:2609.02306},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2609.02306},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_aef047e6b8ee; sha256 1cc0b91ea61920113b8608b40005461e06d338f0aee21e812e2fb81d03b07cb2},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2609.02306. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

Accurate joint encoder offsets are essential for kinematic consistency in humanoid lower limbs, yet existing calibration methods typically require external motion-capture systems or fiducial targets. We present a self-contained calibration framework exploiting only onboard joint encoders and a pelvis-mounted IMU during static double-support contact. The inter-foot transform from forward kinematics must stay constant when both feet are fixed; minimizing its posture-dependent dispersion yields a nonlinear least-squares problem over the 12-dimensional offset vector. A Hessian eigenstructure analysis shows that parallel pitch axes induce a rotational coupling. Orientation residuals then observe only the pitch-offset sum, while translation and posture diversity set the remaining numerical observability. For the A3 pitch-to-roll-to-yaw ordering, hip-roll and hip-yaw excitation reduce hip-pitch coupling. A standing-posture knee prior then anchors the remaining weak pitch-chain decomposition. Simulation and real-machine injection tests show consistent recovery, and on held-out recordings calibration reduces foot-height RMS residuals from 4.26 to 2.20 mm on A3 and from 8.03 to 1.43 mm on A2. An independent LiDAR-inertial reference checks the pitch-coupled channel. Removing an injected pitch offset moves the leg-odometry vertical drift back toward the LiDAR trajectory. A few static double-support stances thus provide contact-consistent corrections for well-excited directions. Individual offsets in the weak pitch chain remain prior-dependent.

Tema degli esploratori: statistica e scienza dei dati (retro-catalogo arXiv: annunci del 2026-09-03 in cs.RO).
Categorie arXiv: Robotics (cs.RO).
Pagina del lavoro: https://arxiv.org/abs/2609.02306 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-10-17T05:39:02.682Z dalla pagina https://arxiv.org/catchup/cs.RO/2026-09-03?abs=True (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).