Singularity analysis of 3-DOF planar parallel continuum robots with constant curvature links

Abstract

This paper presents the singularity analysis of 3-DOF planar parallel continuum robots (PCR) with three identical legs. Each of the legs contains two passive conventional rigid 1-DOF joints and one actuated planar continuum link, which bends with a constant curvature. All possible PCR architectures featuring such legs are enumerated and the kinematic velocity equations are provided for each of them. Afterwards, a singularity analysis is conducted based on the obtained Jacobian matrices, providing a geometrical understanding of singularity occurences. It is shown that while loci and occurrences of type II singularities are mostly analogous to conventional parallel kinematic mechanisms (PKM), type I singularity occurences for the PCR studied in this work are quite different from conventional PKM and less geometrically intuitive. The study provided in this paper can promote further investigations on planar parallel continuum robots, such as structural design and control.

Tendon-Driven Continuum Robots for Aerial Manipulation—A Survey of Fabrication Methods

“…Generally, these robots can suffer from performance issues, such as an inability to move in certain directions, and lack the required accuracy and stiffness [127][128][129]. Singularity issues in continuum robots are investigated across various types, including TDCRs [130,131], CTR [132] and parallel continuum robots [127,133]. Since singularity is more of a design and modeling-oriented problem, and the primary focus is on the fabrication aspects of TDCRs, this paper does not cover a detailed discussion on continuum robot singularities.…”

Continuum robot state estimation using Gaussian process regression on SE(3)

“…Related work envisions systems consisting of multiple collaborative continuum robots that can join together during operation to form coupled, parallel assemblies, adjusting their kinematic properties to benefit from an increased stiffness or precision [16], [17]. To date, research on both parallel and collaborative continuum robots is mostly concerned with their kinematic, static and dynamic modeling [18], [6], [19], and the characterization of their properties, such as manipulability and compliance [7], [15], reachable workspace [20], singularity conditions [21], [22] and stability [23]. Additionally, novel designs are investigated, with examples ranging from reconfigurable mechanisms [24] to structures featuring additional constraints [25], [26], [27].…”