Dynamic modeling and experimental validation of biomimetic robotic fish

This paper presents a dynamic model of robotic fish which synthesizes both the carangiform and anguilliform swimming modes. The designed robotic fish is divided into three parts: stiff anterior body, flexible rear body, and an oscillating lunate caudal fin. We use unsteady flow theory to analyze the motion of the anterior part and the links, and adopt basic airfoil theory for the caudal fin. By summing up the longitudinal force, lateral force and yaw moment on each propulsive component, the kinematic and dynamic equations of the swimming robotic fish can be derived. The desired propulsive characteristics including forward velocity, sway velocity, angular speed, motion trajectory as well as propulsive efficiency can then be obtained via solving ordinary differential equation. Comparisons between simulation results and real experiments are then conducted and discussed. A good agreement on dynamic characteristics demonstrates the validity of the proposed model