A Creeping Snake-like Robot with Partial Actuation

Enlightened by the creeping gait of natural snakes, snake-like robots swing joints side to side at similar tracks for generating propelling forces. However, it is not always essential to control all joints of a snake-like robot to realize the creeping gait. Therefore, in this paper, a creeping snake-like robot with partially actuated joints has been investigated, towards reducing the redundancy caused by full actuation. Essentially, this approach is composed of the following two concepts: 1) joint equipped with torsion spring mechanism bridges the passive joint to generate rhythm oscillation, and 2) harmonic joint trajectories assist the robot in generating more efficient locomotion. We hereafter demonstrated that the actuated joint dominates passive dynamics of the system, which contributes to overall motion. Meanwhile, different spring stiffness affects the motion performance. Additionally, the interaction between robot and environment through Coulomb friction has been considered to reveal the contributing factors that assist the snake-like robot to yield better locomotion performance.