Locomotion Simulation and System Integration of Robotic Fish with Modular Undulating Fin

This paper presents a design of an underwater vehicle mimicking undulating fins of fish. To mimic the actual flexible fin of real fish, a fin-like mechanism is modeled with a series of connecting linkages. By virtue of a specially designed strip, each link is able to turn and slide with respect to the adjacent link. The driving linkages are used to form a mechanical fin consisting of several fin segments, which are able to produce undulations, similar to those produced by the actual fin rays. Owing to the modular design and the flexible structure of the mechanical fin, we are able to model different types of fin and to construct various biomimetic robots of fish swimming by fin undulations. Workspace of the fin mechanism is derived and the parametric study of the locomotion is presented. The integrated mechatronics design of the fin mechanism together with a buoyancy tank is briefly described. Some qualitative and workspace observations by experiments with the robotic fish are also shown and discussed.