{
  "abstract": "Gravitational torque at manipulator joints persists even at rest and thus determines the continuous torque rating of the actuator. This study developed and validated a passive gravity-compensation joint wherein a cam plate extends a compression-spring link with an offset pin joint. Spring torque was derived by virtual work for an arbitrary cam profile, and the pitch curve was distinguished from the machined surface by a normal-offset correction omitted under the point-contact assumption. Because each harmonic coefficient of the Fourier-parameterized profile contributes to curvature with a weight proportional to the square of its order, raising the order trades curvature for accuracy: over the converged orders, the minimum curvature radius (the largest follower admitted without undercutting) fell by 20–34% while the residual fell 4.5- to 6.9-fold. Attainable accuracy was governed not by stiffness but by whether the springs can store the gravitational energy within their allowable stroke. A 5 kg prototype reduced the peak joint torque by 73.2% on the hysteresis-removed basis but by 20.8% in actuator demand, which includes friction. The measured spring torque matched the model within 5%; half the shortfall from simulation stemmed from a load 11% above design, and the gap between bases from sliding friction.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Robot System Engineering, Keimyung University, 1095 Dalgubeol-daero, Dalseo-gu, Daegu 42601, Republic of Korea",
    "Department of Robot Engineering, Keimyung University, 1095 Dalgubeol-daero, Dalseo-gu, Daegu 42601, Republic of Korea"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Seung-Min Lee",
      "orcid": "0009-0000-5955-5009"
    },
    {
      "affs": [
        1
      ],
      "name": "Seong-yeol Yoo",
      "orcid": "0000-0003-4755-8223"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bm74vs4dqrfr9.bib",
  "cited_by": 0,
  "doi": "10.3390/math14213998",
  "fulltext_url": null,
  "id": "bm74vs4dqrfr9",
  "issns": [
    "2227-7390"
  ],
  "landing_url": "https://www.mdpi.com/2227-7390/14/21/3998",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [],
  "openalex": null,
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/bm74vs4dqrfr9.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T00:23:28Z",
      "native_id": "10.3390/math14213998",
      "source": "crossref",
      "url": "https://www.mdpi.com/2227-7390/14/21/3998"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "issn:2227-7390",
      "subfield": "general"
    }
  ],
  "title": "Passive Gravity Compensation for Robot Manipulator Joints Using a Compression Spring–Cam Mechanism: Modeling, Design, and Experimental Validation",
  "title_text": "Passive Gravity Compensation for Robot Manipulator Joints Using a Compression Spring–Cam Mechanism: Modeling, Design, and Experimental Validation",
  "type": "peer-reviewed",
  "updated_at": "2026-11-05T00:20:49Z",
  "url": "https://research.draconitic.com/paper/bm74vs4dqrfr9",
  "venue": "Mathematics",
  "versions": []
}