Fiber-Optic Force Sensing of Modular Robotic Skin for Remote and Autonomous Robot Control

Robots have taken the place of human operators in hazardous and challenging jobs requiring high dexterity in manipulation, and robots with skin for force and tactile sensing that mimics the function of mechanoreception in animals will be highly dexterous in performing complex tasks. In this study, we propose the design of modular robotic skin, capable of detecting the magnitude and the location of a contact force simultaneously. Each skin module needs three degrees of freedom in sensing in order to estimate the horizontal and the vertical locations of the contact force as well as its magnitude. Force sensing in the proposed skin is enabled by a custom-designed triangular beam structure underneath the skin cover. A force applied to the skin cover causes the bending of the beam, which is detected by fiber optic strain sensors. The result shows the resolutions of 1.45 N for force estimation and 1.85 mm and 1.91 mm for contact localization in horizontal and vertical directions, respectively. We also demonstrate how the proposed skin can be used for remote and autonomous control of commercial robotic arms equipped with an array of the skin modules.