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FBG-based sensor for torque and angle measurement in a Series Elastic Actuator's Spring

SANCHEZ, M. ; LEAL-JUNIOR, A. ; Segatto, M. ; Marques, C. ; Santos, W. ; Siqueira, A. ; Frizera-Neto, A. Frizera-Neto

Applied Optics Vol. 57, Nº 27, pp. 7883 - 7890, September, 2018.

ISSN (print): 2155-3165
ISSN (online): 1559-128X

Journal Impact Factor: 1,763 (in 2008)

Digital Object Identifier: 10.1364/AO.57.007883

Conventional technologies to monitor torque feedback and angle in exoskeleton actuators are bulky, sensitive to misalignments and do not allow for multiplexed operation. Fiber Bragg Grating (FBG)-based sensors are a robust sensing approach that are desirable for multi-parametric monitoring. Temperature,
strain, torque and angle are widely studied in Human Robot Interaction (HRI). In order to acquire the torque and angle of deflection in the torsional spring of a Series Elastic Actuator (SEA), an experimental
setup with the spring and an array of three FBGs is submitted to repeated torques and angles. This paper presents the characterization and validation of FBG-based sensor for measuring by torque and angle variations. A temperature cross-sensitivity is by the use of a non-strain FBG. The developed sensor presented high linearity and small error for torque and angle measurements.