Touch localisation accuracy of OptoSkin optical tactile sensors fabricated from different light-guide materials

Zore, Aleš (author), Stopar, Julija (author), Ogurcovs, Andrejs (author), Butikova, Jelena (author), Aulika, Ilze (author), García-Pueyo, Jorge (author), Cartiel, Sergio (author), Muñoz, Adolfo (author), Laurenzis, Martin (author), Bacher, Emmanuel (author), Munih, Marko (author), Kamnik, Roman (author)

Providing feedback information on touch is crucial in human–robot collaboration tasks. Within the framework of the HE SestoSenso project, a novel approach to touch sensing was developed by exploiting the properties of laser beam propagation in light-guide materials, and three different prototype sensory surfaces were fabricated. For the proposed OptoSkin robot-body optical sensor surface, which employs a time-of-flight (ToF) sensor combined with a light-guide material, a performance evaluation was conducted. Using a controlled test robot cell, two experiments were carried out: a field-of-view (FoV) assessment and a localisation accuracy evaluation. Three different prototypes made from optically transparent but distinct materials were examined: acrylic glass, a 3D-printed material, and soft silicone rubber. The localisation evaluation was performed by applying controlled forces with a robot on a rectangular grid, with a raster spacing of 10 mm between individual touch locations. The evaluation results confirm accurate touch localisation, with an error of less than 5 mm and a variability of less than 2 mm in the sensor FoV. The comparison of the OptoSkin prototypes shows the best performance for the soft silicone rubber material and the worst for the 3D-printed material.

• Language: English
• Keywords: localisation, time-of-flight, LIDAR, optical sensing, robot skin, touch detection
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 12 str.
• Numbering: Vol. 230, pt. E, art. 115810
• PID: 20.500.12556/RUL-184882
• UDC: 681.586:007.52
• ISSN on article: 0030-3992
• DOI: 10.1016/j.optlastec.2026.115810
• COBISS.SI-ID: 285121027
• Publication date in RUL: 16.07.2026

Record is a part of a journal

• Title: Optics and laser technology
• Shortened title: Opt. Laser Technol.
• Publisher: Elsevier
• ISSN: 0030-3992
• COBISS.SI-ID: 26072576

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: okalizacija, čas preleta, LIDAR, optično zaznavanje, robotska koža, zaznavanje dotika

Projects

• Funder: EC - European Commission
• Project number: 101070310
• Name: Physical Cognition for Intelligent Control and Safe Human-Robot Interaction
• Acronym: Sestosenso

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0228
• Name: Analiza in sinteza gibanja pri človeku in stroju