Citation

Chen G, Ti X, Shi L, Hu H. J. Intell. Robotic Syst. 2022; 104(4): e65.

Copyright

(Copyright © 2022, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1007/s10846-022-01610-7

PMID

unavailable

Abstract

The exploration of underwater narrow space is of great significance to study the phenomena, process and laws of life in the ocean. The existing underwater robots are not suitable for the underwater narrow area exploration. Beavers use the hind limbs with webfeet to provide power for flexible movement and possess certain underwater operation ability. In this study, based on the bionic prototype of beaver hind limb, the system structure of beaver-like hind limb is designed, and the paddling motion of beaver-like hind limb is realized by combining servos with rope drive. On this basis, the concept of swimming gait is proposed, and swimming process of beavers with one leg and two legs is analyzed, and the movement sequence of various joints and parts in the swimming is studied. Then, the joint angle data of beavers from the video are obtained and a nonlinear oscillation swimming controller based on Fourier technology is proposed to plan the bionic swimming trajectory of the beaver. Further, the swimming efficiency of the beaver-like hind limb is analyzed, and a model of the swimming efficiency is proposed, which can provide a basis for evaluating its swimming effect. Finally, an experimental platform for the swimming of the beaver-like hind limb is set up, and bionic and reconstruction of the swimming gaits are generated by the nonlinear oscillation swimming controller, and the swimming experiment is carried out. The results show that the propulsion efficiencies of the alternate and synchronous bionic gait are 0.5 × 10−3 and 0.6 × 10−3, higher than those of the generated gaits which are 0.2 × 10−3 and 0.3 × 10−3. This verifies the rationality of the beaver swimming, and lays a theoretical foundation for the swimming realization of the beaver-like hind limb, which provides theoretical support for us to further understand the swimming mechanism of the beaver.

Language: en

Keywords

Beaver-like robot; Hind limb; Swimming efficiency; Swimming gait; Swimming trajectory planning; Underwater narrow space exploration