{"id":25854774,"url":"https://github.com/jchristopherson/friction","last_synced_at":"2026-03-06T10:04:51.283Z","repository":{"id":166606508,"uuid":"642108995","full_name":"jchristopherson/friction","owner":"jchristopherson","description":"A library containing routines for calculating the frictional response of contacting bodies.","archived":false,"fork":false,"pushed_at":"2025-12-19T20:30:25.000Z","size":5055,"stargazers_count":8,"open_issues_count":1,"forks_count":0,"subscribers_count":1,"default_branch":"main","last_synced_at":"2025-12-21T21:45:23.421Z","etag":null,"topics":["coulomb","friction","generalized-maxwell-slip","lu-gre","maxwell","stribeck-friction"],"latest_commit_sha":null,"homepage":"https://jchristopherson.github.io/friction/","language":"Fortran","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"gpl-3.0","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/jchristopherson.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null,"notice":null,"maintainers":null,"copyright":null,"agents":null,"dco":null,"cla":null}},"created_at":"2023-05-17T20:59:08.000Z","updated_at":"2025-09-11T07:41:50.000Z","dependencies_parsed_at":"2024-02-29T13:51:43.891Z","dependency_job_id":"74187cb2-8d17-487e-8f14-259706bf404f","html_url":"https://github.com/jchristopherson/friction","commit_stats":null,"previous_names":["jchristopherson/friction"],"tags_count":2,"template":false,"template_full_name":null,"purl":"pkg:github/jchristopherson/friction","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/jchristopherson%2Ffriction","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/jchristopherson%2Ffriction/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/jchristopherson%2Ffriction/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/jchristopherson%2Ffriction/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/jchristopherson","download_url":"https://codeload.github.com/jchristopherson/friction/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/jchristopherson%2Ffriction/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":30171656,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-03-06T07:56:45.623Z","status":"ssl_error","status_checked_at":"2026-03-06T07:55:55.621Z","response_time":250,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.6:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["coulomb","friction","generalized-maxwell-slip","lu-gre","maxwell","stribeck-friction"],"created_at":"2025-03-01T16:18:06.373Z","updated_at":"2026-03-06T10:04:51.240Z","avatar_url":"https://github.com/jchristopherson.png","language":"Fortran","funding_links":[],"categories":[],"sub_categories":[],"readme":"# friction\nA library containing routines for calculating the frictional response of contacting bodies.\n\n## Status\n[![CMake](https://github.com/jchristopherson/friction/actions/workflows/cmake.yml/badge.svg)](https://github.com/jchristopherson/friction/actions/workflows/cmake.yml)\n[![Actions Status](https://github.com/jchristopherson/friction/workflows/fpm/badge.svg)](https://github.com/jchristopherson/friction/actions)\n\n## Documentation\nThe documentation can be found [here](https://jchristopherson.github.io/friction/).\n\n## Available Models\n- Coulomb Model\n```math\nF = \\text{sgn} \\left( v \\right) \\mu_{c} N\n```\n- Lu-Gre Model\n```math\nF = \\sigma_{0} z + \\sigma_{1} \\frac{dz}{dt} + \\sigma_{2} v\n```\n```math\n\\frac{dz}{dt} = v - \\frac{\\left| v \\right| z}{g(v)}\n```\n```math\ng(v) = a_{1} + \\frac{a_2}{1 + s^{\\alpha}}\n```\n```math\na_{1} = \\frac{\\mu_c N}{\\sigma_{0}}, a_{2} = \\frac{\\mu_s N - \\mu_c N}{\\sigma_{0}}, s = \\frac{\\left| v \\right|}{v_s}\n```\n- Maxwell Model\n```math\nF = k \\delta\n```\n```math\n\\delta_{i+1} = \\text{sgn} \\left( x_{i+1} - x_{i} + \\delta_{i} \\right) \\min \\left( \\left| x_{i+1} - x_{i} + \\delta_{i} \\right|, \\Delta \\right)\n```\n```math\n\\Delta = \\frac{N \\mu_c}{k}\n```\n- Generalized Maxwell Slip Model\n```math\nF = \\sum_{i=1}^{n} \\left( k_i z_i + b_i \\frac{dz_i}{dt} \\right) + b_v v\n```\n```math\n\\begin{equation}\n\\frac{dz_i}{dt} = \n\\begin{cases}\nv \u0026 \\text{if $|z_i| \\le g(v)$} \\\\\n\\text{sgn} \\left( v \\right) \\nu_i C \\left( 1 - \\frac{z_i}{\\nu_i g(v)} \\right) \u0026 \\text{otherwise}\n\\end{cases}\n\\end{equation}\n```\n```math\ng(v) = a_{1} + \\frac{a_2}{1 + s^{\\alpha}}\n```\n```math\na_{1} = \\frac{\\mu_c N}{\\sigma_{0}}, a_{2} = \\frac{\\mu_s N - \\mu_c N}{\\sigma_{0}}, s = \\frac{\\left| v \\right|}{v_s}\n```\n```math\n\\sum_{i=1}^{n} \\nu_i = 1\n```\n- Stribeck Model\n```math\nF = \\text{sgn} \\left( v \\right) \\left( \\mu_c N + N \\left( mu_s - mu_c \\right) \\exp(-|\\frac{v}{v_s}|^2) \\right) + b_v v\n```\n- Modified Stribeck Model\n```math\nF = k \\delta + b_v v\n```\n```math\n\\delta_{i+1} = \\text{sgn} \\left( x_{i+1} - x_{i} + \\delta_{i} \\right) \\min \\left( \\left| x_{i+1} - x_{i} + \\delta_{i} \\right|, g(v) \\right)\n```\n```math\ng(v) = a_{1} + a_2 \\exp(-|\\frac{v}{v_s}|^2)\n```\n```math\na_{1} = \\frac{\\mu_c N}{k}, a_{2} = \\frac{\\mu_s N - \\mu_c N}{k}\n```\n\n## References:\n1. Al-Bender, Farid \u0026 Lampaert, Vincent \u0026 Swevers, Jan. (2004). Modeling of dry sliding friction dynamics: From heuristic models to physically motivated models and back. Chaos (Woodbury, N.Y.). 14. 446-60. 10.1063/1.1741752. \n2. Rizos, Demosthenis \u0026 Fassois, Spilios. (2009). Friction Identification Based Upon the LuGre and Maxwell Slip Models. Control Systems Technology, IEEE Transactions on. 17. 153 - 160. 10.1109/TCST.2008.921809. \n3. Al-Bender, Farid \u0026 Lampaert, Vincent \u0026 Swevers, Jan. (2005). The generalized Maxwell-Slip model: A novel model for friction simulation and compensation. Automatic Control, IEEE Transactions on. 50. 1883 - 1887. 10.1109/TAC.2005.858676. \n4. Tjahjowidodo, Tegoeh \u0026 Al-Bender, Farid \u0026 Brussel, H.. (2005). Friction identification and compensation in a DC motor. IFAC Proceedings Volumes. 32. 10.3182/20050703-6-CZ-1902.00093. \n5. Lampaert, Vincent \u0026 Al-Bender, Farid \u0026 Swevers, Jan. (2003). A generalized Maxwell-slip friction model appropriate for control purposes. 4. 1170- 1177 vol.4. 10.1109/PHYCON.2003.1237071. \n6. Al-Bender, Farid \u0026 Swevers, Jan. (2009). Characterization of friction force dynamics. Control Systems, IEEE. 28. 64 - 81. 10.1109/MCS.2008.929279. \n7. Al-Bender, Farid. (2010). Fundamentals of friction modeling. Proceedings - ASPE Spring Topical Meeting on Control of Precision Systems, ASPE 2010. 48. \n8. Al-Bender, Farid \u0026 Moerlooze, K.. (2011). Characterization and modeling of friction and wear: an overview. International Journal Sustainable Construction \u0026 Design. 2. 19-28. 10.21825/scad.v2i1.20431. ","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fjchristopherson%2Ffriction","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fjchristopherson%2Ffriction","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fjchristopherson%2Ffriction/lists"}