Design and Development of Large-Area FBG-Based Sensing Skin for Collaborative Robotics

Advancements in the field of collaborative robotics have led to a closer cooperation between humans and machines. Sharing the same environment, safety and adaptive control becomes of paramount importance in human-robot interaction. Thus, tactile feedback technologies are crucial to perceive contacts. This work presents the design and development of a polymeric artificial skin, mimicking the human sense of touch in perceiving and localizing pressure over a large area, and its integration on a custom human-like robotic forearm. The sensing system consisted of a curved soft matrix embedding an optical fiber equipped with 16 distributed Fiber Bragg Gratings (FBGs). To estimate the sensitivity of the tactile sensor array, a preliminary mechanical characterization was performed by means of force-controlled indentations. Results show a high correlation between the applied load and the corresponding output of the sensors. In particular, the median value of the sensitivity resulted in 0.26 nm.N-1, with 0.08 nm.N-1 interquartile range. These promising results call for further investigation on spatial sensitivity and force range, contact localization and calibration of the presented artificial skin.