An advancement in underwater acoustic sensors has been made using MEMS cantilevers for marine sensing robotics. A directional hydrophone is formed by these MEMS cantilevers that detect the direction from which the incoming signal is coming. Due to their micrometre size and lightweight, these hydrophones can be mounted in autonomous underwater vehicles such as AUVs and ROVs. We can locate enemy submarines, underwater drones, and warships through this microsensor, thus improving our defence. Furthermore, this Vector Hydrophone will aid in developing submarine communication systems, sonobuoys, ROVs, SONARs, fish tracking, oceanographic surveys, and marine life surveys.
During the past two decades, microelectromechanical systems (MEMS) have attracted many researchers, especially microsensors and actuators. Among them, pressure sensors are essential. Different types of pressure sensors exist based on various physical properties, such as piezoresistive, piezoelectric, capacitive, magnetic, and electrostatic. This work presents a novel, highly sensitive, and directional piezoelectric cantilever-based micro-electro-mechanical system (MEMS) device realized by a biomimetic approach of the fish lateral line system for marine sensing robotics. The device will consist of ten cantilevers with different lengths in a cross-shape configuration made by a piezoelectric thin film (PZT, ZnO, BaTiO3 ) embedded between the top and bottom metals (Pt/Al) used as electrodes. This unique design of cantilevers in circular shape has the advantage of directional response in the frequency range of 300 Hz to 300 kHz. A comparative study of these piezoelectric materials was performed analytically through a finite element method to design, model, and simulate our device in COMSOL software. Solid mechanics, electrostatic and pressure acoustic are the physics used to study the behaviour of the microcantilevers. The simulations of cantilever microstructures with different lengths are performed from 100 μm to 1000 μm. The micro-cantilever consists of metal (Pt/Al) as electrodes and piezoelectric materials (PZT, ZnO, BaTiO3 ) on a silicon substrate. As a result of varying pressure, we studied displacement and voltage. An almost linear relationship exists between induced voltage and applied force. Simulation results show that PZT has demonstrated the best performance in these materials. Maximum potential voltage was shown 1.9 mV by PZT material cantilever with 29 µm displacement. Simulations can provide guidelines for designing and optimizing piezoelectric micro-cantilever pressure sensors based on comparative analysis.