Propulsion modeling of caudal fin driving system on balloon fish robot

Recently, biomimetic robots combining the characteristics of fish robots and airship robots have been studied. In this work, we consider balloon fish robots (BFR). This paper presents our understanding of the BFR motion obtained through simulations and experimental results. The simulation of the BFR motion is based on a traveling-wave equation, defined as the product of a sine wave and quadratic curve. In this study, we derived an equation of motion for BFR and conducted an experiment to measure the thrust force. By solving the equation of motion with the Runge–Kutta method, we are able to calculate theoretical values for the propulsion velocity of BFR. We validate the simulation by comparing theoretical and experimental propulsion speed values. As a future task, we will measure BFR thrust at more parameters.