Dynamic tail modeling and motion analysis of a beaver-like robot

The beaver-like underwater robot can crawl and swim, playing a significant role in the exploration of amphibious environments. The robot's fan-shaped tail offers partial forward propulsion and enhances motion stability. However, a comprehensive method for modeling this tail motion is lacking. This paper introduces a segmented approach to dynamic modeling, building both propulsion and lift models for the robot's beaver-like tail. The approach integrates hydrodynamics with material mechanics to formulate a fan-shaped flexible dynamics theory. A performance index is established to quantify the tail's motion performance, offering a theoretical foundation for its evaluation. To validate the dynamic model and assess motion performance under varying swing amplitude coefficients, both simulations and experiments are undertaken. An optimal swing amplitude coefficient of 2 is identified, setting the stage for future developments in robotic motion control. This work may also advance dynamic modeling and analysis in other biomimetic underwater robots.