An improved semi-empirical model for a body and/or caudal fin (BCF) fish robot

To develop useful applications for the underwater robots, the first step is to study its performance, such as thrust force or swimming velocity. In order to avoid numerous parameter studies in evaluating its performance, the prediction model plays an important role. As fish´s swimming includes the kinematic of its own body and the hydrodynamic interaction with the surrounding fluid, it is difficult to formulate a precise mathematical model by purely analytical approaches. This paper offers a semi-empirical method to model the performance of a BCF (body and/or caudal fin) biomimetic fish robot. By using a dimensional statistical method, a semi-empirical model for predicting the thrust force generated by a BCF oscillation swimming mode is derived. This model shows good prediction capability. The predicted results are in good agreement with the experiment data. Therefore, the proposed modeling method can be used to solve the engineering problem concerned without a complex theory derivation.