Abstract
Cosserat rod models for soft robots usually construct sectional stiffness by summing material properties over a common cross-section. This assumption becomes inaccurate for trimmed helicoid arms, where load-bearing helix domains are separated and connected only through sparse fused crossings. This paper formulates a separated-section constitutive law that evaluates each helix domain in its local frame and pulls its constitutive response back to the backbone, yielding an effective backbone stiffness. Sparse-fusion mechanics captures the additional compliance caused by relative motion between neighboring domains and determines channel-wise reduction profiles $η_c(s/L)$ for bending, torsion, and extension. The resulting effective sectional stiffness is strongly anisotropic: bending and extension are reduced by about one order of magnitude, whereas torsion remains close to the effective backbone stiffness. The resulting sectional law is embedded in a geometrically exact dynamic Cosserat model with GVS discretization and routed-tendon actuation. Across 103 measured configurations, the three datasets give pooled normalized position errors of $7.7 \ \%$, $6.7 \ \%$, and $7.8 \ \%$, while each full-arm solve requires approximately $0.3 \ \mathrm{s}$ on one CPU core (Intel Xeon, Cascade Lake, $2.8 \mathrm{GHz}$), enabling rapid model-based planning, state and load estimation, and morphology--control co-design for architected soft robots.
Keywords
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Cite this article
APA 7
Qin, Z., Hou, L., Zhong, Z., Sun, Y., Xin, W., Zhang, Y., Qi, J., Wang, J., Wang, P., Nazeer, M. S., Tan, Y. J., Renda, F., & Laschi, C. (2026). Cosserat Modeling of Trimmed Helicoid Soft Arms with a Separated-Section Constitutive Law. https://omanscience.com/en/articles/cosserat-modeling-of-trimmed-helicoid-soft-arms-with-a-separated-section-constitutive-law
MLA 9
Qin, Zhihang, et al. "Cosserat Modeling of Trimmed Helicoid Soft Arms with a Separated-Section Constitutive Law." https://omanscience.com/en/articles/cosserat-modeling-of-trimmed-helicoid-soft-arms-with-a-separated-section-constitutive-law.
Chicago (author–date)
Qin, Zhihang, Linxin Hou, Zeyu Zhong, Yuchen Sun, Wenci Xin, Yueheng Zhang, Ji Qi, Jie Wang, Peiyi Wang, Muhammad Sunny Nazeer, Yu Jun Tan, Federico Renda, and Cecilia Laschi. 2026. "Cosserat Modeling of Trimmed Helicoid Soft Arms with a Separated-Section Constitutive Law." https://omanscience.com/en/articles/cosserat-modeling-of-trimmed-helicoid-soft-arms-with-a-separated-section-constitutive-law.
Harvard
Qin, Z., Hou, L., Zhong, Z., Sun, Y., Xin, W., Zhang, Y., Qi, J., Wang, J., Wang, P., Nazeer, M. S., Tan, Y. J., Renda, F. and Laschi, C. (2026) 'Cosserat Modeling of Trimmed Helicoid Soft Arms with a Separated-Section Constitutive Law', Available at: https://omanscience.com/en/articles/cosserat-modeling-of-trimmed-helicoid-soft-arms-with-a-separated-section-constitutive-law.
Vancouver
Qin Z, Hou L, Zhong Z, Sun Y, Xin W, Zhang Y, et al. Cosserat Modeling of Trimmed Helicoid Soft Arms with a Separated-Section Constitutive Law. https://omanscience.com/en/articles/cosserat-modeling-of-trimmed-helicoid-soft-arms-with-a-separated-section-constitutive-law
IEEE
Z. Qin, L. Hou, Z. Zhong, Y. Sun, W. Xin, Y. Zhang, J. Qi, J. Wang, P. Wang, M. S. Nazeer, Y. J. Tan, F. Renda, and C. Laschi, "Cosserat Modeling of Trimmed Helicoid Soft Arms with a Separated-Section Constitutive Law," https://omanscience.com/en/articles/cosserat-modeling-of-trimmed-helicoid-soft-arms-with-a-separated-section-constitutive-law.