High Sensitivity Photon Pressure Sensitive Skin of Piercing Robot Based on Balloon-Shaped Fiber Optic Sensor

In this paper, a photonic skin sensor based on a balloon-shaped optical fiber structure cascading a Fiber Bragg Grating (FBG) is proposed, which can simultaneously sense pressure and temperature. When the photonic skin feels pressure, the built-in polymer micro-cap is squeezed, causing a change in the radius of the balloon-shaped structure. At the same time, the capillary-enclosed FBG can be used for temperature compensation. The pressure sensitivity of the photon skin sensor can reach 6.556 nm/mN in the range of 0-0.5 mN and the temperature sensitivity can reach -0.192 nm/°C in the range of 30-50 °C. The demodulation of the dual parameter matrix shows that the error rates of pressure and temperature measurements are less than 0.5% and 2.01%, respectively. On this basis, the sensor is applied to robotic arm-assisted puncture experiment detection, and the five states of the puncture process are analyzed. Based on the backpropagation (BP) neural network for repeated training, the results show that its accuracy remains at 98.7%, indicating that the sensor has good robustness. The development of this sensor shows application potential in the field of robotic intelligent skin in the future.