Enhanced performance of bionic ciliary piezoelectric microsensor for hydrodynamic perception

This work presents a bionic ciliary piezoelectric microsensor in d₃₃ mode for enhancing performance of self-powered hydrodynamic perception. The sensor is composed of a cylindrical pillar emulating the fish cilium and a piezoelectric sensing diaphragm imitating the hair cell. Interdigital electrodes are designed on both sides of the sensing diaphragm to realize the radial polarization, whose pattern consists of a few semi-circular rings connected to each other. Based on the receptance method and Kirchhoff plate theory, a mathematical model is established to evaluate the resonance frequency of the sensor. The output characteristics of the sensor are numerically obtained by coupling the drag force acquired by computational fluid dynamics into the finite element model. The effects of key structural parameters on the sensor response are further investigated for the purpose of optimizing the device design. Prototypes are fabricated by the microelectromechanical systems technology and stereolithography, characterized using the impedance spectrum and tested employing a dipole stimulus. The experimental values of the sensor response to hydrodynamic flow velocities are in fine agreement with the numerical simulation. The results indicate a high sensitivity of 2.483 V/(m/s) and a relatively flat frequency response of the sensor. This work provides important guidance for designing the more efficient ciliary microsensor that can conduct flow field perception for underwater autonomous vehicles.