A Variable Curvature Model for Multi-Backbone Continuum Robots to Account for Inter-Segment Coupling and External Disturbance

Chen, Yuyang; Wu, Baibo; Jin, Jiabin; Xu, Kai

doi:10.1109/lra.2021.3058925

Cited by 30 publications

(12 citation statements)

References 29 publications

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“…By applying the Cosserat rod theory, Jones et al [27] introduced a variable curvature model for computing the shape configuration of a continuum robot in 3-D space. Considering inter-subsegment coupling and external disturbance, Chen et al [28] proposed a variable curvature model for quasi continuum robots. Deformation of the manipulator can be determined by using force-torque balance equations.…”

Section: Introductionmentioning

confidence: 99%

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Zheng 郑,

Ding 丁,

Liu 刘

et al. 2024

Chinese Phys. B

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Continuum robots with high flexibility and compliance have the capability to operate in confined and cluttered environments. To enhance the load capacity while maintaining robot dexterity, we propose a novel non-constant subsegment stiffness (NSS) structure for tendon-driven quasi continuum robots (TDQCR) comprising rigid-flexible coupling subsegments. Aiming at real-time control applications, we present a novel static-to-kinematic modeling approach to gain a comprehensive understanding of the TDQCR model. The analytical subsegment-based kinematics for the multisection manipulator is derived based on screw theory and product of exponentials formula, and the static model considering gravity loading, actuation loading, robot constitutive laws is established. Additionally, the effect of tension attenuation caused by routing channel friction is considered in the robot statics, resulting in improved model accuracy. The root mean square (RMS) error between the outputs of the static model and the experimental system is less than 1.63% of the arm length (0.5 m). By employing the proposed static model, a mapping of bending angles between the configuration space and the subsegment space is established. Furthermore, motion control experiments are conducted on our TDQCR system, and the results demonstrate the effectiveness of the static-to-kinematic model.

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Section: Introductionmentioning

confidence: 99%

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Zheng 郑,

Ding 丁,

Liu 刘

et al. 2024

Chinese Phys. B

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“…Biological systems are always providing a source of inspiration for engineers, making a new class of robotic paradigms, which are referred to as continuum robots. [ 1 ] Compared with traditional robots composed of rigid links and joints, continuum robots featured with both softness and compliance exhibit reduced complexity in interactions with the environment in application scenarios, such as minimally invasive surgery, [ 2 ] environment exploration, [ 3 ] and safe human–robot interaction. [ 4 ] As a promising candidate for constructing safe human‐centered robots, continuum robots are shifting the mechanical design of intelligent machines from the sole use of rigid materials toward the use of compliant materials.…”

Section: Introductionmentioning

confidence: 99%

Bioinspired Continuum Robots with Programmable Stiffness by Harnessing Phase Change Materials

Zhang¹,

Wang²,

Chen³

et al. 2023

Adv Materials Technologies

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are referred to as continuum robots. [1] Compared with traditional robots composed of rigid links and joints, continuum robots featured with both softness and compliance exhibit reduced complexity in interactions with the environment in application scenarios, such as minimally invasive surgery, [2] environment exploration, [3] and safe human-robot interaction. [4] As a promising candidate for constructing safe human-centered robots, continuum robots are shifting the mechanical design of intelligent machines from the sole use of rigid materials toward the use of compliant materials. [5] However, these robots are challenged by the inherent contradiction between softness and load-bearing capacity when dealing with stress application scenarios, since the carrying capacity of compliant materials is much worse than that of rigid materials. [6] Aiming at this inherent challenge in existing continuum robots, a hybrid robotic system that combines both soft and rigid materials may figure out the contradiction between the structural stiffness and shape adaption capability. [7] Tensegrity structures, created by Fuller, may provide a novel paradigm for the continuum robotic design. [8] The combination of rigid components and high softness endows this structure with desirable characteristics found in both classically rigid and Continuum robots offer significant advantages over traditional ones in some specific scenarios, such as urban search and rescue, minimally invasive surgery, and inspection of cluttered environments. However, motions and/or operations of existing continuum robots always suffer from those limitations in varying curvature interaction scenarios because of the homogeneity and singleness of the structural stiffness. Herein, inspired by the mechanism of an elephant trunk for regulating local stiffness, a three-segment continuum robot constructed by tensegrity structure, which relies on a stiffness tunable material, with its Young's modulus switchable between 1.79 and 271.62 MPa to achieve the robotic stiffness programmable characteristics, is proposed. For predicting the robotic configuration with varying stiffness distribution, a mechanical model based on the framework of the finite element method is derived. Theoretical predictions reveal that the curvature of each segment can be regulated by programming stiffness of the smart materials; therefore, the customizable design can offer an effective route for real-time robotic interactions. By evaluating motion characteristics, stiffness performance, and conformal interaction capability, the experimental results demonstrate that the robot can freely regulate the configuration on-demand, which may provide a foundation for the application of continuum robots with programmable stiffness for interacting with unstructured environments.

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“…[ 1,2 ] Compared to conventional robots composed of rigid links and joints, continuum robots, which can be characterized by their continuous core structure, known as backbone, have higher versatility, [ 3 ] greater security, [ 4 ] and stronger adaptability. [ 5 ] Hence, they can potentially be used in a variety of applications such as research and rescue, [ 6 ] minimally invasive surgery, [ 7 ] and planetary exploration. [ 8 ] Compliant grasping has recently become another interesting application for continuum robots when interacting with complex environments as well as humans.…”

Section: Introductionmentioning

confidence: 99%

Versatile Like a Seahorse Tail: A Bio‐Inspired Programmable Continuum Robot For Conformal Grasping

Zhang¹,

Hu²,

Li³

et al. 2022

Advanced Intelligent Systems

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Compliant grasping is an important function of continuum robots that interact with humans and/or unpredictable environments. However, the existing robots often have cross‐sections that remain constant along their length. This causes the robots to exhibit poor grasping ability, especially when dealing with objects with diverse curvatures. Here, inspired by the high adaptability of seahorse tails in grasping, a cable‐driven continuum robot with tapered tensegrity, capable of conformally grasping objects with various curvatures is proposed. To characterize the effects of tapering on robotic kinematics, a mechanical model is derived using a multi‐body dynamic framework for both predicting the configuration and developing a control strategy for cables. Theoretical predictions indicate that the curvature of each unit can be regulated by altering the length of the cables, allowing the robot to conform to objects with curvatures ranging from 1.48 to 28.21 m−1. Further, a continuum robot is employed, and the control strategy that can be used for grasping floating objects when the curvature of the objects is used as the input is tested. The robotic design, which presents an example of embedded physical intelligence, can inspire in situ characterization techniques for collecting floating contaminants.

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A Variable Curvature Model for Multi-Backbone Continuum Robots to Account for Inter-Segment Coupling and External Disturbance

Cited by 30 publications

References 29 publications

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Bioinspired Continuum Robots with Programmable Stiffness by Harnessing Phase Change Materials

Versatile Like a Seahorse Tail: A Bio‐Inspired Programmable Continuum Robot For Conformal Grasping

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