Design and Analysis of a Novel Swimming Mechanism Inspired from Frogs

This article presents a design of a novel swimming mechanism based on a linkage mechanism. The generated motions of the proposed mechanism mimic the purely aquatic locomotion of frogs such as Xenopus laevis (X. laevis), including both the motions of the hind legs and the webbed foot. A six-bar linkage mechanism is employed in this study combing with a spatial linkage mechanism to simplify the overall mechanism. Attributes to the optimal design, the number of Degrees of Actuations (DoA) reduces to two in each hindlimb, which realizes miniaturization in the current study. Kinematic analysis is conducted to analyze the locomotion of the spatial mechanism. The hydrodynamic model based on the blade element theory is established to estimate the swimming performance of the designed mechanism. The peak thrust (approximately 0.2 N) is dramatically larger than the minimum drag (-0.023 N) observed in the experiment which increases the efficiency of the prototype's swimming.