A new concept and technologies of multi-legged underwater robot for high tidal current environment

In this paper, we present a new concept of multi-legged seabed robot for high tidal current environment. The robot moves on seabed by walking with 4 or 6 legs which is different moving mechanism from the existing underwater thrust system such as screw or Caterpillar. The main concept to endure the high current is utilization of hydrodynamic forces acting on the body and legs. The advantage of this concept is that the robot is able to have high stability in positioning as well as that the robot is less disturbs the seabed environment than other thrust system. In order to optimize the configuration of the leg with respect to tidal current, an optimization problem is formulated. And a simplified model of hydrostatic and hydrodynamic forces acting on the legs is presented. Presented model can be used for optimization of body and leg configurations, and for drag-optimal path planning of legs. Because the shape of leg is a main factor to the hydro dynamic forces, a design of slender leg is also presented in this paper.