Concentric Push–Pull Robots: Planar Modeling and Design

Oliver-Butler, Kaitlin; Childs, Jake A.; Daniel, Adam; Rucker, D. Caleb

doi:10.1109/tro.2021.3104249

Cited by 18 publications

(12 citation statements)

References 40 publications

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“…Alternative designs with helical pre-curvature [51] or patterned tubes [52,53] improve performance, and hybrid designs with features from both concentric tube and tendon-driven robots have been recently developed. [54,55]…”

Section: Concentric Tube Robotsmentioning

confidence: 99%

Continuum Robots: An Overview

Russo

Sadati

Dong

et al. 2023

Advanced Intelligent Systems

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When thinking of robots, the image that immediately springs to mind is either an android, designed to resemble human beings and mimic their behavior, or an industrial manipulator, for example, a large machine of rigid steel working in an assembly line. However, robotic systems of multiple forms have been developed to carry out the most diverse tasks, with designs that evolved from readily available structures, such as vehicles, or inspired by nature. In the last decade, more and more bioinspired designs have been enabled by advances in computer science, materials, and manufacturing. Among them, continuum robots, inspired by snakes, trunks, and tendrils, are characterized by a compliant backbone capable of continuous bending, whose shape (configuration, i.e., position and orientation along the backbone curve) is controlled by applying loads through onboard "intrinsic" actuators (e.g., pneumatics or hydraulics) or transmission elements (e.g., tendons, rods, or compliant tubes) that are pushed/pulled from an extremity of the backbone ("extrinsic actuation"). These robots have flexible bodies with a high length to cross-section diameter ratio and are uniquely suited to tasks that require the deployment of tools or sensors with a long reach into tortuous and narrow paths. [1] Continuum robots were first developed in the 1960s [2] and rose to prominence in the late 1990s, [3] when they were often called elephant trunk, [4] tentacle/tendril, [5] or flexible [6] manipulators. Whereas other robots were characterized by intrinsic actuation and larger sizes, research on continuum robots first focused on miniaturization for medical applications, [7,8] leading to extrinsic actuation to enable leaner designs. Recently, continuum robots have been developed for a wider range of applications, including manufacturing, aerospace, search and rescue, and nuclear. In such scenarios, the infinite degrees of freedom (DoFs) of these slender robots enable inspection and intervention in areas that cannot be accessed by conventional robots (e.g., tunnels [9] and gas turbines [10] ).An exhaustive literature search (see Appendix) outlines a surging interest in continuum robots, with a 19.6% average annual growth in publications between 2012 and 2021 (continuum robot search on Web of Science). Three main topics can be observed in recent literature surveys, listed in Table 1. DesignTendon-driven and concentric tube robots are predominant in surveys, but they are not the only design solutions. [18] This richer literature can be attributed to intense research effort toward medical and other small-scale applications when compared to larger-scale tasks (e.g., manipulation) where intrinsic actuation is advantageous.

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Section: Concentric Tube Robotsmentioning

confidence: 99%

Continuum Robots: An Overview

Russo

Sadati

Dong

et al. 2023

Advanced Intelligent Systems

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“…Throughout this work, we assume that the length of each link is fixed, while the bending can be actively controlled. We further assume, that bending occurs in arcs with a constant curvature, which is a common assumption for a variety of actuation methods ( Webster III and Jones, 2010 ), e.g., utilizing tendons ( Rao et al., 2021 ), multi-backbones ( Simaan et al., 2004 ), push-pull rods ( Oliver-Butler et al., 2021 ), polymer actuators ( Moghadam et al., 2015 ) or pneumatic actuators ( Garcia et al., 2020 ; 2021 ). We do not consider additional methods of actuation, such as translating or rotating the bases of the continuum links, a practice often done in PCR with passively deforming links.…”

Section: Planar 3-dof Pcr Designsmentioning

confidence: 99%

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

2023

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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.

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“…They were all met except one: the earlier prototype of the bending segment failed to sustain a transversal force of 1 N. This section describes a structural optimisation conducted to maximise the force that can be delivered at the end of a flexible instrument shaft without buckling or reaching superelasticity. Oliver-Butler et al 22 conducted an optimisation for single-sided cut-outs but only optimising the cut-out depth to maximise the bending segment stiffness.…”

Section: Bending Segment Structural Optimisationmentioning

confidence: 99%

Design and modelling of an anisotropic continuum robot end-effector for single-port access surgery suturing

Vandebroek

Legrand

Vercauteren

et al. 2023

Advances in Mechanical Engineering

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Single port access surgery has brought many advantages and new challenges to the field of minimally invasive surgery. In principle, many of these challenges can be addressed through robotics. Continuum robots in particular have seen a surge in interest in recent years for their miniaturisation potential. However, many applications with these robots have been developed for contactless or low-force tasks. This paper tackles several barriers to high-force tasks with continuum robots such as suturing for Open Spina Bifida repair. A novel continuum robot end-effector is proposed. The end-effector is composed of a distal bending segment and hybrid gripper. First, the novel hybrid gripper specifically designed for continuum robots is introduced. The hybrid gripper can function both as a general surgical gripper and as a needle driver while overall keeping the required input force limited. Second, an optimisation of the continuum structure of the distal bending segment is conducted. The objective of this optimisation is to sustain high tip forces – required by the said high-force contact tasks – while keeping deformations acceptable. Third, a quasi-static model that predicts the coupled effect of bending and gripping is derived. This model predicts the deformation of the continuum structure that is induced by the gripping action itself. It could hence be used to compensate for such deformation and establish a stable grip with the otherwise flexible instruments. Finally, experiments are conducted to validate the new designs and the model. The hybrid gripper has a diameter of [Formula: see text] mm, a length of [Formula: see text] mm and can hold securely a needle with a [Formula: see text] N input force, outputting a [Formula: see text] N gripping force. The optimised bending segment is validated for Open Spina Bifida suture: it can bend freely up to 90° and it can support a [Formula: see text] N tip load up to a 35° bending angle. The bending and gripper model error varies between 1% and 14.55%, yielding useful results to predict the shape of the bending segment and potentially compensate for the disturbance created by actuating the gripper.

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Concentric Push–Pull Robots: Planar Modeling and Design

Cited by 18 publications

References 40 publications

Continuum Robots: An Overview

Continuum Robots: An Overview

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

Design and modelling of an anisotropic continuum robot end-effector for single-port access surgery suturing

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