Underwater bionic whisker sensor based on triboelectric nanogenerator for passive vortex perception

Seals, as well as other terrestrial and marine animals, utilize their whiskers as key tactile sensors to locate and track underwater wakes. Herein, an underwater bionic whisker sensor (UBWS) based on triboelectric nanogenerator was designed for capturing complex stimuli produced by moving aquatic species and using the acquired signals to follow their hydrodynamic trails. The UBWS is inspired by the structural properties of seal whiskers and incorporates a free-standing triboelectric nanogenerator, which gives it ability to capture vortices passively. The design of the UBWS is fully flexible and self-powered, which eliminates the need for an external power source while retaining the capability of high sensitivity to stimuli. Moreover, the output signal's interaction with the movement parameters was highly correlated, and this principle was utilized to determine the relative motion state of an underwater moving object. Experiments demonstrated that the developed UBWS was capable of perceiving the hydrodynamic trails created by moving objects underwater. These new insights into the biological foundation of tactile perception through whiskers provide new design criteria for developing efficient underwater robotic sensors.