Leg-Pattern Modeling for Swimming of Underwater Walking Robot Considering Hydrodynamic Forces

The needs for underwater robots increased to explore and develop ocean resources safely and efficiently. Traditionally propeller-based ROVs(Remotely Operated Vehicles) and AUVs(Autonomous Unmanned Vehicles) have been used for ocean exploration and development. However, over the past decade, a new type of underwater robot that uses legs has emerged. These robots offer advantages such as stable movement over uneven or complex sea floor terrains and minimizing ecosystem disruption. However, due to legged locomotion, they have slower movement speeds compared to traditional underwater robots. To overcome this limitation, a swimming function using legs has been introduced. This paper aims to discuss the design of the swimming motion for underwater legged robots. Additionally, we define the hydrodynamic resistance that occurs due to swimming with legs underwater and calculate it to determine the thrust generated during swimming.