Fiber Bragg Gratings in CYTOP Fibers Embedded in a 3D-Printed Flexible Support for Assessment of Human–Robot Interaction Forces

Materials

MariaJosé Pontes¹  Arnaldo Leal-Junior²  Camilo Díaz²  Kyriacos Kalli²  Carlos Marques³  Anselmo Frizera-Neto⁴  Antreas Theodosiou⁴ 

[1] Physics Department, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal;Graduate Program of Electrical Engineering, Federal University of Espírito Santo, Vitória 29075-910, Brazil;;Instituto de Telecomunicações and I3N &Photonics and Optical Sensing Research Laboratory, Cyprus University of Technology, 3036 Limassol, Cyprus;

关键词: fiber Bragg gratings;    polymer optical fiber;    wearable devices;    soft materials;    additive layer manufacturing;   

DOI  :  10.3390/ma11112305

来源: DOAJ

【 摘 要 】

We developed a flexible support with embedded polymer optical fiber (POF) sensors for the assessment of human⁻robot interaction forces. The supports were fabricated with a three-dimensional (3D) printer, where an acrylonitrile butadiene styrene (ABS) rigid structure was used in the region of the support in which the exoskeleton was attached, whereas a thermoplastic polyurethane (TPU) flexible structure was printed in the region where the users placed their legs. In addition, fiber Bragg gratings (FBGs), inscribed in low-loss, cyclic, transparent, optical polymer (CYTOP) using the direct-write, plane-by-plane femtosecond laser inscription method, were embedded in the TPU structure. In this case, a 2-FBG array was embedded in two supports for human⁻robot interaction force assessment at two points on the users’ legs. Both FBG sensors were characterized with respect to temperature and force; additionally, the creep response of the polymer, where temperature influences the force sensitivity, was analyzed. Following the characterization, a compensation method for the creep and temperature influence was derived, showing relative errors below 4.5%. Such errors were lower than the ones obtained with similar sensors in previously published works. The instrumented support was attached to an exoskeleton for knee rehabilitation exercises, where the human⁻robot interaction forces were measured in flexion and extension cycles.

【 授权许可】

Unknown