Experimental research and floating gait planning of crablike robot

Hai-Long Wang,Gang Wang,Qi-Feng Zhang,Qi-Yan Tian,Yun-Long Fan,Xing-Ya Yan

doi:10.1177/1687814020904853

Abstract

In order to improve the swimming performance of a paddle-propelled crablike robot, the sequence and parameters of swimming gait are planned according to the bionic swimming mechanism. Based on the bionic prototype of Portunus trituberculatus, the structure scheme of a leg–paddle hybrid driven robot is proposed with the functions of walking on land, crawling on seabed, and swimming underwater. By analyzing the underwater propulsion mechanism of single paddle and hydrodynamic performance of double paddles cooperatively propulsion, four direct swimming gaits are planned and the corresponding attitude changes are theoretically analyzed. Then, the numerical simulation and direct swimming experiments are carried out to verify the effectiveness of proposed gaits and correctness of force analysis. In alternate swimming gait of lift-based mode, the robot swims forward in a rolling attitude, with an advantage of the minimum water resistance and the optimum swimming velocity and efficiency. The influence of flapping frequency and relative phases of paddles on the swimming velocity shows the trend of raise first and then fall.

Highlights

The shoal between ocean and land has attracted increasing attention for scientists who devote themselves to scientific research, environmental monitoring, and energy exploration, which can promote the development of shoal operating robots.[1,2] The driving form of shoal operating robot can be divided into single type and combination type.[3]
The leg–paddle hybrid driving crablike robot is proposed in this article by taking Portunus trituberculatus as bionic prototype, combining the leg’s crawling mode and paddle’s flapping mode, by which the robot can walk on land or seabed and swimming underwater
In order to study the influence of phase difference DfBP between feathering motion and flapping motion in lift-based mode on propulsion performance of swimming paddle, the following motion parameters are set for numerical simulation, which are U = 0.2 m/s, DfTCA = 358, and DfCBA = 408

Summary

Introduction

The shoal between ocean and land has attracted increasing attention for scientists who devote themselves to scientific research, environmental monitoring, and energy exploration, which can promote the development of shoal operating robots.[1,2] The driving form of shoal operating robot can be divided into single type and combination type.[3]. In order to study the influence of phase difference DfBP between feathering motion and flapping motion in lift-based mode on propulsion performance of swimming paddle, the following motion parameters are set for numerical simulation, which are U = 0.2 m/s, DfTCA = 358, and DfCBA = 408. Comparing the speed curves of the two gaits, the average speed of alternate gait is higher than that of synergy gait at the same flapping frequency except for f = 1.2 Hz. The reason is that the additional pitching moment is produced due to the interaction between swimming paddle and water in synergy gait, which results in a pitching movement. At the same flapping frequency, the average speed of alternate gait is higher than that of synergy gait

Declaration of conflicting interests

Conclusion