Soft Bionic Skin With Touch-Slip and Thermal Perception Using Double-Layer Distributed FBG Sensing Array

A flexible bionic skin using fiber Bragg grating (FBG) is proposed in this paper, and a double-layer distributed sensing array unit is designed which can realize the detection of pressure, sliding information and environmental temperature. Based on finite element simulation analysis, the embedding position of the FBG array unit in the packaging material is optimized, and a prototype was built. A series of tactile, sliding and temperature experiments were done. The experimental results show that the tactile and temperature perception of the flexible skin has good linearity, and its sensitivity is 7.287 nm/MPa and 13 pm/°C, respectively. Adaptive Network-based Fuzzy Inference System (ANFIS) is used to compensate the tactile experimental data, which can effectively reduce the influence of temperature as a non-target parameter on tactile and the coupling error is less than 4%. The sliding information of the object can be obtained from the characteristic signal of sliding sensing. Finally, Empirical Mode Decomposition (EMD) and Support Vector Machines (SVM) are used to optimize the sliding data, which can effectively identify the sliding direction and speed of the object. In addition, the skin also has a simple structure, strong ability to be free of the electromagnetism interfering, flexibility, low cost and so on, which is expected to be used in the intelligent machine in the future.