Efficiency on snake robot locomotion with constant and variable bending angles

Serpentine motion is the most commonly seen locomotion style for snakes. Hirose proposed his famous kinematic equation to describe the serpentine motion which is widely used in the locomotion of snake-like robots. Based on the equation, the serpentine motion has constant amplitude of bending angles for the whole length of a snake. However, based on the observation of a real snake, the bending angle seems to be variable throughout the body. Variable bending angle models are therefore proposed in this paper to study the efficiency of the snake motions. The results show that cases with variable bending angles achieve better motion efficiency than the case with constant bending angles as described in the Hirose equation.