Design and Integration of a Novel Spatial Articulated Robotic Tail

In nature, tails are a key feature in numerous animals that help stabilize, maneuver, manipulate, and/or propel. However, prior research on robotic tails has focused on limited degree of freedom (DOF), pendulum-like structures designed for a single function. This paper presents a novel robotic tail system capable of spatial motion to generate spatial loading. The roll-revolute-revolute robotic tail (R3RT) is a serpentine robotic structure with a roll-DOF at the tail base, and two independently actuated coplanar bending segments composed of several links connected by parallel revolute joints. A dynamic model of the tail is presented, along with considerations for sensing the robot's state and controlling the tail. The inertial loading capabilities of the tail are analyzed using the dynamics model and experimentally validated using an integrated prototype of the R3RT to present loading analysis and the performance benefits of tail articulation. Results of the analysis are promising and indicate clear directions for improvement in a future work.

I. Introduction

In Nature, tails assist propulsion, stabilization, maneuvering, and manipulation. However, other than undulating or swimming snake robots, the focus has been on leg design and control to propel, maneuver, and stabilize. By offsetting some maneuvering and stabilization functions to a tail, the leg design and control complexity can be reduced.