Design and Development of Miniaturized Underwater Robot Driven by Piezoelectric Actuator Inspired by Cephalopod

Miniaturized bionic underwater robots hold significant development potential in areas such as resource exploration, underwater rescue, and military operations due to their superior biomimetic and flexible design. However, there are challenges in developing miniaturized underwater robots in terms of operating mechanisms and structural design. In this study, inspired by the efficient jet propulsion mechanisms of cephalopods, a miniaturized underwater robot driven by a linear piezoelectric actuator is designed and developed. The proposed design adopts a direct drive linear piezoelectric actuator, which eliminates the requirement for complex transmission mechanisms, thereby reducing structural complexity. To systematically evaluate the operation performance, a coupling simulation is developed to investigate the fluid-structure interaction and optimize the nozzle diameter. Experimental validation is conducted to investigate the influence of the nozzle diameter on the thrust force and swimming velocity. The results reveal that a nozzle diameter of 25 mm yields optimal performance, with the prototype achieving a maximum thrust force of 56 mN and a swimming velocity of 0.4 BL/s. This research not only demonstrates the feasibility of applying the linear piezoelectric actuator for underwater propulsion in a simple and efficient approach but also provides a design method for the development of compact, high-performance miniaturized bionic robots.