Unified Approach to the Motion Design for a Snake Robot Negotiating Complicated Pipe Structures

Abstract

A unified method for designing the motion of a snake robot negotiating complicated pipe structures is presented. Such robots moving inside pipes must deal with various “obstacles,” such as junctions, bends, diameter changes, shears, and blockages. To surmount these obstacles, we propose a method that enables the robot to adapt to multiple pipe structures in a unified way. This method also applies to motion that is necessary to pass between the inside and the outside of a pipe. We designed the target form of the snake robot using two helices connected by an arbitrary shape. This method can be applied to various obstacles by designing a part of the target form specifically for given obstacles. The robot negotiates obstacles under shift control by employing a rolling motion. Considering the slip between the robot and the pipe, the model expands the method to cover cases where two helices have different properties. We demonstrated the effectiveness of the proposed method in various experiments.

Gait Generation Method of Snake Robot Based on Main Characteristic Curve Fitting

“…It is difficult to analytically represent complex target forms of snake robots. Using the method proposed in [ 12 ] can avoid the problem that the torsion tends to infinity, but the obtained target curve configuration analytic function is complicated. Therefore, it is necessary to come up with a method that can obtain the target curve that is easy to analyze, as well as to avoid the situation that the curvature, , or torsion, , and torsion, , is infinite.…”

“…Yamada mathematically modeled the target curve based on the Frenet-Serret reference frame, decomposed the curvature into the corresponding axis directions of the yaw and pitch joints on the backbone, and deduced the rotation angles of each joint of the snake robot [ 10 ]. Furthermore, adaptation to the environment is achieved by combining torque feedback with motion planning using this approximation method [ 11 , 12 ]. When the curvature and torsion of the target curve are known, it is easy to obtain the joint angle of the snake robot.…”

Editorial: Biological and Robotic Inter-Limb Coordination

“…Starting with a snake-like robot, Inazawa et al (2021) proposed a unified model-based method for designing the motion of a robot to deal with complicated pipe structures. The central control with a model considering slippage between robot and pipe coordinates the connected pitch-axis and yaw-axis joints of the robot body.…”

S-shaped rolling gait designed using curve transformations of a snake robot for climbing on a bifurcated pipe

“…Rollinson and Choset [4] used a compliance controller to direct a snake robot to automatically adapt to the shape of the fork, but this method can only be used for climbing inside pipes. [5][6][7] proposed methods for achieving climbing motion along curved pipes by designing target curves. However, the solution strategies mentioned in [3][4][5][6][7] can be applied only to climbing inside pipes.…”