Abstract: Aiming at the difficulties in the research on the propulsion mechanism and propulsion performance caused by the randomness, uncertainty and complexity of real pectoral motion, and the problem in bionic research on fexible pectoral fin, a kinematics model of propulsion motion of flexible pectoral fin is established in stages based on the research on a great deal of observation of the structure and motion characteristic of sun fish pectoral fin, then the simulation analysis of the change process of its morphology is developed. The simulation result shows that the kinematics model established describes the motion law and morphology well. Therefore, the research settles the theoretical basis of the further research on the propulsion mechanism, propulsion performance and bionics of flexible pectoral fin.

Key words: Flexible pectoral fin, Kinematics model, Labriform mode