A Biomimetic Piezoelectric Composite-Driven Undulation Underwater Robotic Structure: Characteristic Analysis and Experimental Investigation

Numerous proposals and recommendations have been made in the development of underwater undulation robots, but very few studies have focused on the undulation characteristics of undulation robots. The undulating mode of the clearnose skate utilizing the activation of the pectoral fins in undulatory bursts is particularly suitable for slow and efficient swimming. Inspired by the working principle of the clearnose skate, herein, an undulation robotic structure is presented. Considering the hydrodynamic skeleton and propulsion mechanism of the clearnose skate, the solution is based on a piezoelectric composite for realizing undulatory propulsion. This approach leverages the converse piezoelectric effect and modal coupling to produce the desired undulating motion, thereby achieving the undulation design of the robot. The proposed robotic structure can realize the propulsion mode using piezoelectric composites to undulate in the same direction and can use the clockwise or counterclockwise undulation of piezoelectric composites to achieve the steering mode. In addition, finite element analysis is employed as an approach to investigate the undulation characteristics and transient vibration characteristics of the robot. The operational efficiency of the robotic structure is assessed through experiments. The results show that the propulsion mode achieves the speed of 3.33 body-length s-1. The steering mode exhibits the steering velocities of 17.4 deg s-1. A biomimetic undulation underwater robotic structure is proposed. The piezoelectric composites of the structure will generate traveling waves under the electric excitation. The proposed robotic structure exhibits dual functionality, capable of functioning in both propulsion and steering. Additionally, this study introduces a finite element analysis-based approach to analyze the undulation characteristics and time domain behavior of the structure.image (c) 2023 WILEY-VCH GmbH