Generalized Singularity Analysis of Snake-Like Robot

Abstract

The purpose of this paper is to elucidate a generalized singularity analysis of a snake-like robot. The generalized analysis is denoted as analysis of singularity of a model which defines all designable parameters such as the link length and/or the position of the passive wheel as arbitrary variables. The denotation is a key point for a novelty of this study. This paper addresses the above new model denotation, while previous studies have defined the designable parameters as unique one. This difference makes the singularity analysis difficult substantively. To overcome this issue, an analysis method using redundancy of the snake-like robot is proposed. The proposed method contributes to simplify singularity analysis concerned with the designable parameters. The singular configurations of both the model including side-slipping and the one with non side-slipping are analyzed. As the results of the analysis, we show two contributions. The first contribution is that a singular configuration depends on designable parameters such as link length as well as state values such as relative angles. The second contribution is that the singular configuration is characterized by the axials of the passive wheels of all non side-slipping link. This paper proves that the singular configuration is identified as following two conditions even if the designable parameters are chosen as different variables and the model includes side-slipping link. One is that the axials of passive wheels of all non side-slipping links intersect at a common point. Another one is that axials of passive wheels of all non side-slipping links are parallel.

Special Feature on Advanced Mobile Robotics

“…Zhang et al [46] analyzed head-raising motion of the snake robot, which is related to the angle sequences of roll, pitch and yaw. Another snake-like robot and its analysis was presented by Nansai et al [47]. Singular configuration analysis was provided in the work.…”

A Nonholonomic Model and Complete Controllability of a Three-Link Wheeled Snake Robot

“…It is well known that, when one chooses the angles between the platforms as controls, "singular" configurations [65,70,71] appear in the multilink systems. When the robot passes through these configurations, the constraint reactions begin to increase without bound, which results in the nonholonomic model becoming inapplicable.…”