Abstract: Tough environments such as swamps and shoals deserve a snake-like robot to have better adaptability to the environments. After deep investigation of the latest researches on amphibious snake-like robot, a new amphibious snake-like robot is developed. The robot is composed of 9 waterproofed modular universal units and has smooth motion ability on ground and in water. A simplified Serpenoid curve is used to generate the serpentine gait, which is the basic two-dimensional gait of snake-like robots. Combining the basic motions on two perpendicular planes, the horizontal plane and the vertical plane, diverse gaits can be got through a heuristic three-dimensional gait generation method, including the lateral serpentine gait, the S-shape rolling gait, and the helical rolling gait, among which the S-shape rolling gait on the ground and helical rolling gait in the water are newly found. The robot’s motion ability on the ground and in the water is also validated by experiments. The results of the gait performance analysis obtained must be useful for the position and posture control of the robot in amphibious environments.

Key words: Amphibious snake-like robot, Gait control, Serpenoid curve, Snake-like robot