Design Considerations and Redundancy Resolution for Variable Geometry Continuum Robots

Abah, Colette; Orekhov, Andrew L.; Simaan, Nabil

doi:10.1109/icra.2018.8460722

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…Compared with the existing variable-diameter mechanisms by an angled scissor mechanism [39], a shape memory alloy actuator [40], and McKibben water hydraulic artificial muscles [46], the newly proposed double pyramid deployable mechanism has stronger structural stability. This variable-diameter method has the advantages of faster, more stable, and higher accuracy.…”

Section: Discussionmentioning

confidence: 99%

“…j 0 T(α, β, γ) and j 0 T(s, k, ϕ) are the kinematic equation of j parallel drive units expressed by Euler angles (α j , β j , γ j ) and arc parameters (s j , k j , ϕ j ), respectively. The solved s j , k j , and ϕ j are brought into the forward solution equation (39), and the tip trajectories of the robot are simulated by MATLAB, as shown in figure 7. It can be seen that the simulated tip points of the three-section are on the defined trajectory, which verifies the correctness of the inverse kinematics solution method.…”

Section: Multisection Inverse Kinematicsmentioning

confidence: 99%

“…so that they can quickly change their structural size like flexible biological organs in the operating environment is a key challenge in the field of robotics. Abah et al [39] proposed a variable-diameter conceptual design for multi-backbone continuum robots by an angulated scissor mechanism. Laschi et al [40] designed a soft robot arm inspired by octopuses which can achieve diameter reduction by transverse actuators made of shape memory alloy.…”

Section: Introductionmentioning

confidence: 99%

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Design and kinematic of a dexterous bioinspired elephant trunk robot with variable diameter

et al. 2022

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How to further improve the dexterity of continuum robots so that they can quickly change their structural size like flexible biological organs is a key challenge in the field of robotics. To tackle this dexterity challenge, this paper proposes a soft-rigid coupled bioinspired elephant trunk robot with variable diameter, which is enabled by combining a soft motion mechanism with a novel rigid variable-diameter mechanism (double pyramid deployable mechanism). The integration of these two mechanisms has produced three significant beneficial effects: i) The coexistence of multi-degree-of-freedom motion capability and variable size function greatly improves the dexterity of the elephant trunk robot. ii) The motion refinement can be improved by structural amplification, making up for the low resolution of soft actuators. iii) Its stiffness can be increased by enlarging its diameter, while its reachable workspace can be increased by decreasing its diameter. Thus, the elephant trunk robot can optimize its performance when facing different tasks by opening and closing the rigid variable-diameter mechanism. Further, we established a kinematic model of the elephant trunk robot by the structure discretization method and the principle of mechanism equivalence, and experimentally verified its reasonableness. The demonstration experiments show that the elephant trunk robot has good flexibility. This work provides a new variable diameter configuration for continuum robots, and presents a method of how to analyze the kinematics of continuum mechanisms using rigid mechanism theory.

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Section: Discussionmentioning

confidence: 99%

Section: Multisection Inverse Kinematicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design and kinematic of a dexterous bioinspired elephant trunk robot with variable diameter

et al. 2022

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“…Mechanical Design: A continuum robot can tune its stiffness by varying its diameter with a reconfigurable mechanism; [75] locking tendons along the backbone; [76] integrating a movable stiffer element into the backbone; [77,78] or exploiting an anisotropic distribution of the flexural stiffness of the structure. [79]…”

Section: Stiffening Solutionsmentioning

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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“…For example, controllers for hyper-redundant robots have been developed that simultaneously command both end effector pose and backbone shape (Chirikjian and Burdick 1994, 1995). Redundancy resolution has also been used to reduce actuation forces of tendon-actuated (Camarillo et al 2008; Yip and Camarillo 2014) and variable diameter continuum robots (Abah et al 2018), avoid buckling in multi-backbone continuum robots (Simaan 2005), improve stability in magnetically controlled continuum catheters (Edelmann et al 2017), avoid joint limits in multi-backbone robots (Bajo et al 2012) and robots with multiple rolling joints (Berthet-Rayne et al 2018), and reduce visual occlusion of the endoscope field of view during surgery (Sarli and Simaan 2017).…”

Section: Introductionmentioning

confidence: 99%

Exceeding traditional curvature limits of concentric tube robots through redundancy resolution

Anderson,

Hendrick,

Rox

et al. 2023

The International Journal of Robotics Research

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Understanding elastic instability has been a recent focus of concentric tube robot research. Modeling advances have enabled prediction of when instabilities will occur and produced metrics for the stability of the robot during use. In this paper, we show how these metrics can be used to resolve redundancy to avoid elastic instability, opening the door for the practical use of higher curvature designs than have previously been possible. We demonstrate the effectiveness of the approach using a three-tube robot that is stabilized by redundancy resolution when following trajectories that would otherwise result in elastic instabilities. We also show that it is stabilized when teleoperated in ways that otherwise produce elastic instabilities. Lastly, we show that the redundancy resolution framework presented here can be applied to other control objectives useful for surgical robots, such as maximizing or minimizing compliance in desired directions.

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Design Considerations and Redundancy Resolution for Variable Geometry Continuum Robots

Cited by 7 publications

References 18 publications

Design and kinematic of a dexterous bioinspired elephant trunk robot with variable diameter

Design and kinematic of a dexterous bioinspired elephant trunk robot with variable diameter

Continuum Robots: An Overview

Exceeding traditional curvature limits of concentric tube robots through redundancy resolution

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