A roller skating mode-based amphibious spherical robot

A father-son robot system is developed to implement complicated underwater operations. In order to move from the land to the water and work underwater automatically, the amphibious father robot has the quadruped walking actuation mode and the water-jet actuation mode. However, the walking velocity on land is limited by the complex conditions and the quadruped walking actuation mode is not suitable for the movement on the ramp. This paper proposes a new roller skating actuation mode for the amphibious father robot to improve the movement performance on the even terrains and ramp. Four passive wheels are installed on the four legs of the robot. Two structures of the father robot in roller skating mode are designed with different installation methods of the wheels. Two sliding gaits are proposed for each structure. Then the sliding experiments were carried out on the even terrain and a slope respectively to evaluate the performance of the robot. From the results, the robot has a higher sliding performance in the second structure. At a control frequency of 5.56 Hz, we get a maximum sliding velocity of 37.5 cm/s.