Exploring the Effect of Fin Shape on Fin-Propelled Robot's Swimming Efficiency Based on Numerical Simulation

Marine garbage pollution and pipeline leakage seriously affect the fragile marine ecosystem; using humor labor to solve these issues is not only dangerous but also inefficient. In order to tackle this engineering problem, this paper develops an efficient underwater robot based on sea turtle's multi-legged structure and fin-propelling dynamics. The first-generation robot designed in this project has a main unit based on a cylindrical sealed capsule, and its quadrupedal structure enables the robot to not only swim underwater, but also to walk on the seafloor to perform tasks. The bionic legs of the robot can move up and down as well as forward and backward, which in turn enables the main unit to swim in a manner similar to that of sea turtles and other marine organisms. At the same time, a peristaltic pump is used to realize sinking and floating by changing the robot's self-weight. The robot can be remotely controlled by cell phone via Wi-Fi. In the second generation of the robot, this project aims to improve the robot's swimming efficiency through a combination of numerical simulation and physical experiments, exploring the effect of different shapes of fins on the swimming speed of the robot. By selecting and installing the best shape of fins on the robot, combined with the redesign of the leg linkage structure and the adjustment of the robot's center of gravity position, the robot's swimming speed significantly increases from 0.0357 m/s to 0.133 m/s. Finally, in the process of iteration, the project optimizes the control algorithm of the mechanical arm to realize precise operation, and adjusts the robot's turning radius and speed so that it can move around underwater pipeline more flexibly, thus achieving the realization of the robot's application scenarios for underwater garbage collection and pipeline inspection.