Modular continuum robots possess significant versatility across various scenarios;however,conventional assembling methods typically rely on linear connection between modules.This limitation can impede the robotic inte...Modular continuum robots possess significant versatility across various scenarios;however,conventional assembling methods typically rely on linear connection between modules.This limitation can impede the robotic interaction capabilities,especially in specific engineering applications.Herein,inspired by the assembling pattern between the femur and tibia in a human knee,we proposed a multidirectional assembling strategy.This strategy encompasses linear,oblique,and orthogonal connections,allowing a two-module continuum robot to undergo in-situ reconfiguration into three distinct initial configurations.To anticipate the final configuration resulting from diverse assembling patterns,we employed the positional formulation finite element framework to establish a mechanical model,and the theoretical results reveal that our customizable strategy can offer an effective route for robotic interactions.We showcased diverse assembling patterns for coping with interaction requirements.The experimental results indicate that our modular continuum robot not only reconfigures its initial profile in situ but also enables on-demand regulation of the final configuration.These capabilities provide a foundation for the future development of modular continuum robots,enabling them to be adaptable to diverse environments,particularly in unstructured surroundings.展开更多
Tendon-driven continuum robots achieve continuous deformations through the contraction of tendons embedded inside the robotic arms.For some continuum robots,the constant curvature assumption-based kinematic modeling c...Tendon-driven continuum robots achieve continuous deformations through the contraction of tendons embedded inside the robotic arms.For some continuum robots,the constant curvature assumption-based kinematic modeling can be accurate and effective.While for other cases,such as soft robots or robot-environment interactions,the constant curvature assumption can be inaccurate.To model the complex deformation of continuum robots,the geometrically exact beam theory(may also be called the Cosserat rod theory)has been used to develop computational mechanics models.Different from previous computational models that used finite difference schemes for the spatial discretization,here we develop a three-dimensional geometrically exact beam theory-based finite element model for tendon-driven continuum robots.Several numerical examples are presented to show the accuracy,efficiency,and applicability of our new computational model for tendon-driven continuum robots.展开更多
The inherent compliance of continuum robots holds great promise in the fields of soft manipulation and safe human–robot interaction.This compliance reduces the risk of damage to the manipulated object and its surroun...The inherent compliance of continuum robots holds great promise in the fields of soft manipulation and safe human–robot interaction.This compliance reduces the risk of damage to the manipulated object and its surroundings.However,continuum robots possess theoretically infinite degrees of freedom,and this high flexibility usually leads to complex deformations when subjected to external forces and positional constraints.Describing these complex deformations is the main challenge in modeling continuum robots.In this study,we investigated a novel variable curvature modeling method for continuum robots,considering external forces and positional constraints.The robot configuration curve is described using the developed mechanical model,and then the robot is fitted to the curve.A ten-section continuum robot prototype with a length of 1 m was developed in order to validate the model.The feasibility and accuracy of the model were verified by the ability of the robot to reach target points and track complex trajectories with a load.This work was able to serve as a new perspective for the design analysis and motion control of continuum robots.展开更多
This study addresses the challenges of tendon-driven continuum robots in terms of high-performance joint design,high-accuracy and-efficiency mechanical modeling,and inverse kinetostatic-based control.First,a general d...This study addresses the challenges of tendon-driven continuum robots in terms of high-performance joint design,high-accuracy and-efficiency mechanical modeling,and inverse kinetostatic-based control.First,a general design framework for rigid–flexible coupled continuum robots is proposed inspired by the Freedom and Constraint Topology theory.Based on this framework,a novel claw-type continuum robot with high torsion resistance,high-precision positioning,and excellent anti-buckling performance is developed.Consequently,a novel kinetostatic model named the separated beam equilibrium model(SBEM)is proposed by solving the equilibrium equations for each unit individually rather than recursively,which achieves high modeling accuracy and efficiency.Finally,an iterative inverse kinetostatic-based control method involving mechanic factors is proposed.Comparative experimental results demonstrate that the claw-type continuum robot outperforms the twin-pivot continuum robot in terms of torsion resistance by more than 300 times.Moreover,the SBEM achieves high morphology estimation accuracy with errors less than 2.91%of manipulator length and high efficiency with more than 20 times improvement for computation reduction compared with the conventional chained beam constraint model.Furthermore,the iterative inverse kinetostatic model-based control obtains a tip error less than 3.70%of manipulator length by only using the open-loop method.The proposed design,modeling,and control method exhibits vast potential for continuum robots when tackling challenging tasks such as inspection,maintenance,and medical surgery in confined and unstructured environments including engine flow paths,nuclear conduits,and human body cavities.展开更多
Magnetic soft continuum robots(MSCRs)integrate remote and untethered actuation capability and inherent biocompatible nature of magnetic fields with the compliance of soft components,holding significant potential in bi...Magnetic soft continuum robots(MSCRs)integrate remote and untethered actuation capability and inherent biocompatible nature of magnetic fields with the compliance of soft components,holding significant potential in biomedical applications.Among various MSCRs,hard-magnetic soft continuum robots(hMSCRs),leveraging materials with hard-magnetic properties,have attracted increasing attention due to their programmable magnetization and large reversible deformations.This review summarizes recent progress in hMSCRs,focusing on the modeling,design,and biomedical applications.First,we introduce fundamental characteristics,actuation mechanisms,and constitutive modeling frameworks of hard-magnetic soft materials.Then,we discuss several typical static and dynamic modeling approaches for two primary categories of hMSCRs:permanent magnet-based and magnetic particle-based systems.Next,design strategies emphasizing structural versatility and functionality are then presented for both types of hMSCRs.Finally,representative biomedical applications in navigation and endoscopy are highlighted,underscoring the transformative potential of hMSCR technologies in clinical practice.展开更多
Tendon-driven continuum robots(TDCR)are widely used in various engineering disciplines due to their exceptional flexibility and dexterity.However,their complex structure often leads to significant manufacturing costs ...Tendon-driven continuum robots(TDCR)are widely used in various engineering disciplines due to their exceptional flexibility and dexterity.However,their complex structure often leads to significant manufacturing costs and lengthy prototyping cycles.To cope with this problem,we propose a fused-deposition-modeling-printable(FDM-printable)TDCR structure design using a serial S-shaped backbone,which enables planar bending motion with minimized plastic deformation.A kinematic model for the proposed TDCR structure based on the pseudo-rigid-body model(PRBM)approach is developed.Experimental results have revealed that the proposed kinematic model can effectively predict the bending motion under certain tendon forces.In addition,analyses of mechanical hysteresis and factors influencing bending stiffness are conducted.Finally,A three-finger gripper is fabricated to demonstrate a possible application of the proposed TDCR structure.展开更多
Parallel continuum robots(PCRs) have attracted increasing attention in the robotics community due to their simplicity in structure,inherence with compliance, and easiness of realization. Over the past decade, a variet...Parallel continuum robots(PCRs) have attracted increasing attention in the robotics community due to their simplicity in structure,inherence with compliance, and easiness of realization. Over the past decade, a variety of novel designs have been reported to enrich their diversity. However, there is a lack of systematic review of these emerging robots. To this end, this paper conducts a comprehensive survey on the mechanism design, kinetostatic modeling and analysis, and performance evaluation. For these robots, kinetostatic modeling plays a fundamental role throughout the design, analysis, and control stages. A systematic review of the existing approaches for kinetostatic modeling and analysis is provided, and a comparison is made to distinguish their differences. As well, a classification is made according to the characteristics of structure and actuation. In addition, performance evaluation on the workspace, stability, and singularity is also overviewed. Finally, the scenarios of potential applications are elaborated, and future research prospects are discussed. We believe that the information provided in this paper will be particularly useful for those who are interested in PCRs.展开更多
This paper presents a continuum manipulator inspired by the anatomical characteristics of the elephant trunk.Specifically,the manipulator mimics the conoid profile of the elephant trunk,which helps to enhance its stre...This paper presents a continuum manipulator inspired by the anatomical characteristics of the elephant trunk.Specifically,the manipulator mimics the conoid profile of the elephant trunk,which helps to enhance its strength.The design features two concentric parts:inner pneumatically actuated bellows and an outer tendon-driven helical spring.The tendons control the omnidirectional bending of the manipulator,while the fusion of the pneumatic bellows with the tendon-driven spring results in an antagonistic actuation mechanism that provides the manipulator with variable stiffness and extensibility.This paper presents a new design for extensible manipulator and analyzes its stiffness and motion characteristics.Experimental results are consistent with theoretical analysis,thereby demonstrating the validity of the theoretical approach and the versatile practical mechanical properties of the continuum manipulator.The impressive extensibility and variable stiffness of the manipulator were further demonstrated by performing a pin-hole assembly task.展开更多
Continuum robots,which are characterized by high length-to-diameter ratios and flexible structures,show great potential for various applications in confined and irregular environments.Due to the combination of motion ...Continuum robots,which are characterized by high length-to-diameter ratios and flexible structures,show great potential for various applications in confined and irregular environments.Due to the combination of motion modes,the existence of multiple solutions,and the presence of complex obstacle constraints,motion planning for these robots is highly challenging.To tackle the challenges of online and flexible operation for continuum robots,we propose a flexible head-following motion planning method that is suitable for scalable and bendable continuum robots.Firstly,we establish a piecewise constant curvature(PCC)kinematic model for scalable and bendable continuum robots.The article proposes an adaptive auxiliary points model and a method for updating key nodes in head-following motion to enhance the precise tracking capability for paths with different curvatures.Additionally,the article integrates the strategy for adjusting the posture of local joints of the robot into the head-following motion planning method,which is beneficial for achieving safe obstacle avoidance in local areas.The article concludes by presenting the results of multiple sets of motion simulation experiments and prototype experiments.The study demonstrates that the algorithm presented in this paper effectively navigates and adjusts posture to avoid obstacles,meeting the real-time demands of online operations.The average time for a single-step solution is 4.41×10^(-5) s,and the average tracking accuracy forcircular paths is 7.8928mm.展开更多
In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aero-engines.The cable-driven continuum robot(CDCR)with twin-pivot compliant mechanisms,which is enabled with flexib...In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aero-engines.The cable-driven continuum robot(CDCR)with twin-pivot compliant mechanisms,which is enabled with flexible deformation capability and confined space accessibility,has emerged as a novel tool that aims to promote the development of intelligence and efficiency for in-situ aero-engine maintenance.The high-fidelity model that describes the kinematic and morphology of CDCR lays the foundation for the accurate operation and control for in-situ maintenance.However,this model was not well addressed in previous literature.In this study,a general kinetostatic modeling and morphology characterization methodology that comprehensively contains the effects of cable-hole friction,gravity,and payloads is proposed for the CDCR with twin-pivot compliant mechanisms.First,a novel cable-hole friction model with the variable friction coefficient and adaptive friction direction criterion is proposed through structure optimization and kinematic parameter analysis.Second,the cable-hole friction,all-component gravities,deflection-induced center-of-gravity shift of compliant joints,and payloads are all considered to deduce a comprehensive kinetostatic model enabled with the capacity of accurate morphology characterization for CDCR.Finally,a compact continuum robot system is integrated to experimentally validate the proposed kinetostatic model and the concept of in-situ aero-engine maintenance.Results indicate that the proposed model precisely predicts the morphology of CDCR and outperforms conventional models.The compact continuum robot system could be considered a novel solution to perform in-situ maintenance tasks of aero-engines in an invasive manner.展开更多
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-const...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 structure for tendon-driven quasi continuum robots(TDQCRs) 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, and 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 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.展开更多
Continuum robot is a new type of biomimetic robot,which realizes the motion by bending some parts of its body.So its path planning becomes more difficult even compared with hyper-redundant robots.In this paper a circu...Continuum robot is a new type of biomimetic robot,which realizes the motion by bending some parts of its body.So its path planning becomes more difficult even compared with hyper-redundant robots.In this paper a circular arc spline interpolating method is proposed for the robot shape description,and a new two-stage position-selectable-updating particle swarm optimization(TPPSO)algorithm is put forward to solve this path planning problem.The algorithm decomposes the standard PSO velocity’s single-step updating formula into twostage multi-point updating,specifically adopting three points as candidates and selecting the best one as the updated position in the first half stage,and similarly taking seven points as candidates and selecting the best one as the final position in the last half stage.This scheme refines and widens each particle’s searching trajectory,increases the updating speed of the individual best,and improves the converging speed and precision.Aiming at the optimization objective to minimize the sum of all the motion displacements of every segmental points and all the axial stretching or contracting displacements of every segment,the TPPSO algorithm is used to solve the path planning problem.The detailed solution procedure is presented.Numerical examples of five path planning cases show that the proposed algorithm is simple,robust,and efficient.展开更多
Continuum robots actuated by flexible rods have large potential applications,such as detection and operation tasks in confined environments,since the push and pull actuation of flexible rods withstand tension and comp...Continuum robots actuated by flexible rods have large potential applications,such as detection and operation tasks in confined environments,since the push and pull actuation of flexible rods withstand tension and compressive force,and increase the structure's rigidity.In this paper,a generalized kinetostatics model for multi-module and multi-segment continuum robots considering the effect of friction based on the Cosserat rod theory is established.Then,the model is applied to a two-module rod-driven continuum robot with winding ropes to analyze its deformation and load characteristics.Four different in-plane configurations under the external load term as S1,S2,C1,and C2 are defined.Taking a bending plane as an example,the tip deformation along thex-axis of these shapes is simulated and compared,which shows that the load capacity of C1 and C2 is generally larger than that of S1 and S2.Furthermore,the deformation experiments and simulations show that the maximum error ratio without external loads relative to the total length is no more than 3%,and it is no more than 4.7%under the external load.The established kinetostatics model is proven sufficient to accurately analyze the rod-driven continuum robot with the consideration of internal friction.展开更多
A novel continuum robot for colonoscopy is presented.The aim is to develop a robot for colonoscopywhich can provide the same functions as conventional colonoscope,but much less pain and discomfort forpatient.In contra...A novel continuum robot for colonoscopy is presented.The aim is to develop a robot for colonoscopywhich can provide the same functions as conventional colonoscope,but much less pain and discomfort forpatient.In contrast to traditional rigid-link robot,the robot features a continuous backbone with nojoints.The continuum robot is 300 mm in total length and 12 mm in diameter that is less than the averagediameter of human colon(20 mm).The robot has a total of 4 DOF(degrees of freedom)and is actuatedremotely by 6 hybrid step motors through super-elastic NiTi wires.Its shape can be changed with highdexterity,therefore ensuring its adaptability to the tortuous shape of human colon.The mechanical struc-ture,kinematics and DSP-based control system are discussed; prototype experiments are carried out tovalidate the kinematics model and to show the motion performances.展开更多
We proposed a method for shape sensing using a few multicore fiber Bragg grating (FBG) sensors ina single-port continuum surgical robot (CSR). The traditional method of utilizing a forward kinematic model tocalculate t...We proposed a method for shape sensing using a few multicore fiber Bragg grating (FBG) sensors ina single-port continuum surgical robot (CSR). The traditional method of utilizing a forward kinematic model tocalculate the shape of a single-port CSR is limited by the accuracy of the model. If FBG sensors are used forshape sensing, their accuracy will be affected by their number, especially in long and flexible CSRs. A fusionmethod based on an extended Kalman filter (EKF) was proposed to solve this problem. Shape reconstructionwas performed using the CSR forward kinematic model and FBG sensors, and the two results were fused usingan EKF. The CSR reconstruction method adopted the incremental form of the forward kinematic model, whilethe FBG sensor method adopted the discrete arc-segment assumption method. The fusion method can eliminatethe inaccuracy of the kinematic model and obtain more accurate shape reconstruction results using only a smallnumber of FBG sensors. We validated our algorithm through experiments on multiple bending shapes underdifferent load conditions. The results show that our method significantly outperformed the traditional methodsin terms of robustness and effectiveness.展开更多
In this paper, the authors present a new control strategy for continuous backbone （continuum） ＂trunk and tentacle＂ robots. Control of this emerging new class of robots has proved difficult due to the inherent comp...In this paper, the authors present a new control strategy for continuous backbone （continuum） ＂trunk and tentacle＂ robots. Control of this emerging new class of robots has proved difficult due to the inherent complexity of their dynamics. Using a recently established full dynamic model, the authors introduce a new nonlinear model-based control strategy for continuum robots. The approach is applicable to continuum robots which can extend/contract as well as bend throughout their structure. Results are illustrated using the mathematical model of a three-section, six-degree of freedom planar continuum robot.展开更多
Continuum robots,characterized by their simplicity,softness,and flexibility,hold significant promise for applications in the field of minimally invasive surgery.Nevertheless,the majority of existing continuum robots a...Continuum robots,characterized by their simplicity,softness,and flexibility,hold significant promise for applications in the field of minimally invasive surgery.Nevertheless,the majority of existing continuum robots are plagued by issues such as a single stiffness property and restricted operation space.To address these challenges,we have engineered a multistiffness nested cooperative magnetic continuum robot grounded in low melting point alloy(LMPA).The core components of this innovative robot are an orientator and a tracker.By integrating neodymium magnets within the orientator,the robot can effectively respond to the external magnetic field,thereby endowing it with a navigation capability.Furthermore,through precisely adjusting the phase and amplitude of the waveforms generated by the signal generator along the X,Y,and Z axes,the Helmholtz coils can produce programmable and controllable magnetic fields.This enables the robot to map out diverse paths,including the typical L-shaped,S-shaped,and U-shaped trajectories.Functionally,when equipped with a shape memory alloy(SMA)gripper,the robot can move steadily and precisely grasp objects within complex passages.This remarkable performance strongly attests to the robot's potential application value in industrial inspection,minimally invasive surgery,and other relevant fields.展开更多
Magnetic continuum robots(MCRs)have garnered substantial attention as a new class of flexible robotic systems capable of navigating complex and confined spaces with remarkable dexterity.By combining continuous,deforma...Magnetic continuum robots(MCRs)have garnered substantial attention as a new class of flexible robotic systems capable of navigating complex and confined spaces with remarkable dexterity.By combining continuous,deformable structures with remotely applied magnetic fields,MCRs achieve contactless,remote manipulation,making them well‐suited for medical ap-plications.This review introduces recent advances in MCR research,focusing on design principles,structural configurations,and control strategies.Various MCR designs and structures,including those integrated with permanent magnets,magnetic matter,ferromagnetic sphere,and micro coil,are discussed.Furthermore,different magnetic actuation platforms are intro-duced,and the level of MCR automation is classified based on control strategies.Key intelligent manipulation capabilities of MCRs,including navigation,delivery,printing,grasping,imaging,and sensing are explored.Finally,future development pri-orities and directions are identified to provide insights for advancing intelligent robotic systems.展开更多
The design and analysis of continuum robots have consistently been a prominent research focus in the field of mechanics.However,portable continuum robots with minimal spatial occupancy,which have great potential for a...The design and analysis of continuum robots have consistently been a prominent research focus in the field of mechanics.However,portable continuum robots with minimal spatial occupancy,which have great potential for applications such as search and rescue,are scarcely available.This paper presents a novel helical-coiled multi-segment flexible continuum robot featuring helical deployment and compact design,with an integrated framework for structural design,kinematic modeling,and experimental validation.The design of the helical-coiled multi-segment flexible continuum robot for unstructured environment detection,including a flexible body,an actuation module,a feed module,and a sensing module,is presented systematically.Kinematic models of both single-and multisegment continuum robots were established based on the constant curvature model to analyze the parameter mapping relationship from the end-effector position and orientation to the driving inputs.Furthermore,the feedforward motion of the robot was examined,and an uncoiling strategy based on S-curve compensation was employed to complete the kinematic analysis.Finally,the accuracy of the kinematic model considering the active uncoiling feed motion was validated through experimental analysis,demonstrating the motion characteristics of the continuum robot.Altogether,this study provides a framework for the design and analysis of helical-coiled continuum robots.展开更多
The traditionally articulated manipulator had a single control method,and the limited motion trajectory space was unsuitable for working in an unstructured environment.This paper introduces a control method and optimi...The traditionally articulated manipulator had a single control method,and the limited motion trajectory space was unsuitable for working in an unstructured environment.This paper introduces a control method and optimization for a multijoint manipulator Inspired by snakes'curling and stretching motions.First,we analyze the manipulator’s connection mode and motion planning and propose a new motion method.In addition,we calculated the relevant positions and angles and subdivided the motion of some joints based on the principle of the meta-heuristic algorithm.Ultimately,the manipulator in this mode has a larger workspace and more flexible motion trajectories.The experimental results are consistent with the theoretical analysis,which further proves the feasibility and scalability of the scheme.展开更多
基金supported by the Shenzhen Science and Technology Program(Grant No.20220817165030002,No.GXWD2021B03)National Natural Science Foundation of China(Grant No.52275298 and No.11922203).
文摘Modular continuum robots possess significant versatility across various scenarios;however,conventional assembling methods typically rely on linear connection between modules.This limitation can impede the robotic interaction capabilities,especially in specific engineering applications.Herein,inspired by the assembling pattern between the femur and tibia in a human knee,we proposed a multidirectional assembling strategy.This strategy encompasses linear,oblique,and orthogonal connections,allowing a two-module continuum robot to undergo in-situ reconfiguration into three distinct initial configurations.To anticipate the final configuration resulting from diverse assembling patterns,we employed the positional formulation finite element framework to establish a mechanical model,and the theoretical results reveal that our customizable strategy can offer an effective route for robotic interactions.We showcased diverse assembling patterns for coping with interaction requirements.The experimental results indicate that our modular continuum robot not only reconfigures its initial profile in situ but also enables on-demand regulation of the final configuration.These capabilities provide a foundation for the future development of modular continuum robots,enabling them to be adaptable to diverse environments,particularly in unstructured surroundings.
基金support from the National Natural Science Foundation of China(NSFC Grant No.12072143).J.L.acknowledges the funding support from the National Natural Science Foundation of China(NSFC Grant No.12172160).C.C.acknowledges the financial support from the U.S.National Science Foundation(ECCS-2024649).
文摘Tendon-driven continuum robots achieve continuous deformations through the contraction of tendons embedded inside the robotic arms.For some continuum robots,the constant curvature assumption-based kinematic modeling can be accurate and effective.While for other cases,such as soft robots or robot-environment interactions,the constant curvature assumption can be inaccurate.To model the complex deformation of continuum robots,the geometrically exact beam theory(may also be called the Cosserat rod theory)has been used to develop computational mechanics models.Different from previous computational models that used finite difference schemes for the spatial discretization,here we develop a three-dimensional geometrically exact beam theory-based finite element model for tendon-driven continuum robots.Several numerical examples are presented to show the accuracy,efficiency,and applicability of our new computational model for tendon-driven continuum robots.
基金Supported by National Natural Science Foundation of China(Grant Nos.51975566,61821005,U1908214)Key Research Program of Frontier Sciences,CAS,China(Grant No.ZDBS-LY-JSC011).
文摘The inherent compliance of continuum robots holds great promise in the fields of soft manipulation and safe human–robot interaction.This compliance reduces the risk of damage to the manipulated object and its surroundings.However,continuum robots possess theoretically infinite degrees of freedom,and this high flexibility usually leads to complex deformations when subjected to external forces and positional constraints.Describing these complex deformations is the main challenge in modeling continuum robots.In this study,we investigated a novel variable curvature modeling method for continuum robots,considering external forces and positional constraints.The robot configuration curve is described using the developed mechanical model,and then the robot is fitted to the curve.A ten-section continuum robot prototype with a length of 1 m was developed in order to validate the model.The feasibility and accuracy of the model were verified by the ability of the robot to reach target points and track complex trajectories with a load.This work was able to serve as a new perspective for the design analysis and motion control of continuum robots.
基金supported by the National Natural Science Foundation of China(Grant Nos.52475129,52105117,and 52375125).
文摘This study addresses the challenges of tendon-driven continuum robots in terms of high-performance joint design,high-accuracy and-efficiency mechanical modeling,and inverse kinetostatic-based control.First,a general design framework for rigid–flexible coupled continuum robots is proposed inspired by the Freedom and Constraint Topology theory.Based on this framework,a novel claw-type continuum robot with high torsion resistance,high-precision positioning,and excellent anti-buckling performance is developed.Consequently,a novel kinetostatic model named the separated beam equilibrium model(SBEM)is proposed by solving the equilibrium equations for each unit individually rather than recursively,which achieves high modeling accuracy and efficiency.Finally,an iterative inverse kinetostatic-based control method involving mechanic factors is proposed.Comparative experimental results demonstrate that the claw-type continuum robot outperforms the twin-pivot continuum robot in terms of torsion resistance by more than 300 times.Moreover,the SBEM achieves high morphology estimation accuracy with errors less than 2.91%of manipulator length and high efficiency with more than 20 times improvement for computation reduction compared with the conventional chained beam constraint model.Furthermore,the iterative inverse kinetostatic model-based control obtains a tip error less than 3.70%of manipulator length by only using the open-loop method.The proposed design,modeling,and control method exhibits vast potential for continuum robots when tackling challenging tasks such as inspection,maintenance,and medical surgery in confined and unstructured environments including engine flow paths,nuclear conduits,and human body cavities.
基金supported by the National Natural Science Foundation of China(Grant No.12272369)the support from the Opening Fund of State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment(Grant No.GZ24105)。
文摘Magnetic soft continuum robots(MSCRs)integrate remote and untethered actuation capability and inherent biocompatible nature of magnetic fields with the compliance of soft components,holding significant potential in biomedical applications.Among various MSCRs,hard-magnetic soft continuum robots(hMSCRs),leveraging materials with hard-magnetic properties,have attracted increasing attention due to their programmable magnetization and large reversible deformations.This review summarizes recent progress in hMSCRs,focusing on the modeling,design,and biomedical applications.First,we introduce fundamental characteristics,actuation mechanisms,and constitutive modeling frameworks of hard-magnetic soft materials.Then,we discuss several typical static and dynamic modeling approaches for two primary categories of hMSCRs:permanent magnet-based and magnetic particle-based systems.Next,design strategies emphasizing structural versatility and functionality are then presented for both types of hMSCRs.Finally,representative biomedical applications in navigation and endoscopy are highlighted,underscoring the transformative potential of hMSCR technologies in clinical practice.
基金supported by the teaching funding of TUM School of Engineering and Design.
文摘Tendon-driven continuum robots(TDCR)are widely used in various engineering disciplines due to their exceptional flexibility and dexterity.However,their complex structure often leads to significant manufacturing costs and lengthy prototyping cycles.To cope with this problem,we propose a fused-deposition-modeling-printable(FDM-printable)TDCR structure design using a serial S-shaped backbone,which enables planar bending motion with minimized plastic deformation.A kinematic model for the proposed TDCR structure based on the pseudo-rigid-body model(PRBM)approach is developed.Experimental results have revealed that the proposed kinematic model can effectively predict the bending motion under certain tendon forces.In addition,analyses of mechanical hysteresis and factors influencing bending stiffness are conducted.Finally,A three-finger gripper is fabricated to demonstrate a possible application of the proposed TDCR structure.
基金supported by the National Key R&D Program of China(Grant No. 2022YFB4701200)the National Natural Science Foundation of China(NSFC)(Grant Nos. 52022056 and 51875334)the Innovation Foundation of the Manufacturing Engineering Technology Research Center of Commercial Aircraft Corporation of China(Grant No. COMAC-SFGS-2023-41)。
文摘Parallel continuum robots(PCRs) have attracted increasing attention in the robotics community due to their simplicity in structure,inherence with compliance, and easiness of realization. Over the past decade, a variety of novel designs have been reported to enrich their diversity. However, there is a lack of systematic review of these emerging robots. To this end, this paper conducts a comprehensive survey on the mechanism design, kinetostatic modeling and analysis, and performance evaluation. For these robots, kinetostatic modeling plays a fundamental role throughout the design, analysis, and control stages. A systematic review of the existing approaches for kinetostatic modeling and analysis is provided, and a comparison is made to distinguish their differences. As well, a classification is made according to the characteristics of structure and actuation. In addition, performance evaluation on the workspace, stability, and singularity is also overviewed. Finally, the scenarios of potential applications are elaborated, and future research prospects are discussed. We believe that the information provided in this paper will be particularly useful for those who are interested in PCRs.
基金supported by the National Key R&D Program of China(No.2018YFB1305400)the Major Research Plan of the National Natural Science Foundation of China(No.92048301)+1 种基金the National Natural Science Foundation of China(No.52025054)the Joint Research Fund between the National Natural Science Foundation of China(NSFC)and Shen Zhen(No.U1713201).
文摘This paper presents a continuum manipulator inspired by the anatomical characteristics of the elephant trunk.Specifically,the manipulator mimics the conoid profile of the elephant trunk,which helps to enhance its strength.The design features two concentric parts:inner pneumatically actuated bellows and an outer tendon-driven helical spring.The tendons control the omnidirectional bending of the manipulator,while the fusion of the pneumatic bellows with the tendon-driven spring results in an antagonistic actuation mechanism that provides the manipulator with variable stiffness and extensibility.This paper presents a new design for extensible manipulator and analyzes its stiffness and motion characteristics.Experimental results are consistent with theoretical analysis,thereby demonstrating the validity of the theoretical approach and the versatile practical mechanical properties of the continuum manipulator.The impressive extensibility and variable stiffness of the manipulator were further demonstrated by performing a pin-hole assembly task.
基金supported in part by the Fundamental Research Funds for the Central Universities,China(DUT22GF301).
文摘Continuum robots,which are characterized by high length-to-diameter ratios and flexible structures,show great potential for various applications in confined and irregular environments.Due to the combination of motion modes,the existence of multiple solutions,and the presence of complex obstacle constraints,motion planning for these robots is highly challenging.To tackle the challenges of online and flexible operation for continuum robots,we propose a flexible head-following motion planning method that is suitable for scalable and bendable continuum robots.Firstly,we establish a piecewise constant curvature(PCC)kinematic model for scalable and bendable continuum robots.The article proposes an adaptive auxiliary points model and a method for updating key nodes in head-following motion to enhance the precise tracking capability for paths with different curvatures.Additionally,the article integrates the strategy for adjusting the posture of local joints of the robot into the head-following motion planning method,which is beneficial for achieving safe obstacle avoidance in local areas.The article concludes by presenting the results of multiple sets of motion simulation experiments and prototype experiments.The study demonstrates that the algorithm presented in this paper effectively navigates and adjusts posture to avoid obstacles,meeting the real-time demands of online operations.The average time for a single-step solution is 4.41×10^(-5) s,and the average tracking accuracy forcircular paths is 7.8928mm.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.52105117,52375125,and 52105118).
文摘In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aero-engines.The cable-driven continuum robot(CDCR)with twin-pivot compliant mechanisms,which is enabled with flexible deformation capability and confined space accessibility,has emerged as a novel tool that aims to promote the development of intelligence and efficiency for in-situ aero-engine maintenance.The high-fidelity model that describes the kinematic and morphology of CDCR lays the foundation for the accurate operation and control for in-situ maintenance.However,this model was not well addressed in previous literature.In this study,a general kinetostatic modeling and morphology characterization methodology that comprehensively contains the effects of cable-hole friction,gravity,and payloads is proposed for the CDCR with twin-pivot compliant mechanisms.First,a novel cable-hole friction model with the variable friction coefficient and adaptive friction direction criterion is proposed through structure optimization and kinematic parameter analysis.Second,the cable-hole friction,all-component gravities,deflection-induced center-of-gravity shift of compliant joints,and payloads are all considered to deduce a comprehensive kinetostatic model enabled with the capacity of accurate morphology characterization for CDCR.Finally,a compact continuum robot system is integrated to experimentally validate the proposed kinetostatic model and the concept of in-situ aero-engine maintenance.Results indicate that the proposed model precisely predicts the morphology of CDCR and outperforms conventional models.The compact continuum robot system could be considered a novel solution to perform in-situ maintenance tasks of aero-engines in an invasive manner.
基金Project supported by the National Natural Science Foundation of China (Grant No.61973167)the Jiangsu Funding Program for Excellent Postdoctoral Talent。
文摘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 structure for tendon-driven quasi continuum robots(TDQCRs) 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, and 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 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.
基金Supported by the Fundamental Research Funds for the Central Universities(Grant No.DL09CB02)the Heilongjiang Province Natural Science Fund(Grant No.E201013)
文摘Continuum robot is a new type of biomimetic robot,which realizes the motion by bending some parts of its body.So its path planning becomes more difficult even compared with hyper-redundant robots.In this paper a circular arc spline interpolating method is proposed for the robot shape description,and a new two-stage position-selectable-updating particle swarm optimization(TPPSO)algorithm is put forward to solve this path planning problem.The algorithm decomposes the standard PSO velocity’s single-step updating formula into twostage multi-point updating,specifically adopting three points as candidates and selecting the best one as the updated position in the first half stage,and similarly taking seven points as candidates and selecting the best one as the final position in the last half stage.This scheme refines and widens each particle’s searching trajectory,increases the updating speed of the individual best,and improves the converging speed and precision.Aiming at the optimization objective to minimize the sum of all the motion displacements of every segmental points and all the axial stretching or contracting displacements of every segment,the TPPSO algorithm is used to solve the path planning problem.The detailed solution procedure is presented.Numerical examples of five path planning cases show that the proposed algorithm is simple,robust,and efficient.
基金Supported by National Natural Science Foundation of China(Grant No.51875033)Fundamental Research Funds for the Central Universities of China(Grant No.2021YJS137).
文摘Continuum robots actuated by flexible rods have large potential applications,such as detection and operation tasks in confined environments,since the push and pull actuation of flexible rods withstand tension and compressive force,and increase the structure's rigidity.In this paper,a generalized kinetostatics model for multi-module and multi-segment continuum robots considering the effect of friction based on the Cosserat rod theory is established.Then,the model is applied to a two-module rod-driven continuum robot with winding ropes to analyze its deformation and load characteristics.Four different in-plane configurations under the external load term as S1,S2,C1,and C2 are defined.Taking a bending plane as an example,the tip deformation along thex-axis of these shapes is simulated and compared,which shows that the load capacity of C1 and C2 is generally larger than that of S1 and S2.Furthermore,the deformation experiments and simulations show that the maximum error ratio without external loads relative to the total length is no more than 3%,and it is no more than 4.7%under the external load.The established kinetostatics model is proven sufficient to accurately analyze the rod-driven continuum robot with the consideration of internal friction.
基金Supported by the High Technology Research Development Programme of China (No. 2007AA042105)the Program for Changjiang Scholars and Innovative Research Team in University (IRT0423)
文摘A novel continuum robot for colonoscopy is presented.The aim is to develop a robot for colonoscopywhich can provide the same functions as conventional colonoscope,but much less pain and discomfort forpatient.In contrast to traditional rigid-link robot,the robot features a continuous backbone with nojoints.The continuum robot is 300 mm in total length and 12 mm in diameter that is less than the averagediameter of human colon(20 mm).The robot has a total of 4 DOF(degrees of freedom)and is actuatedremotely by 6 hybrid step motors through super-elastic NiTi wires.Its shape can be changed with highdexterity,therefore ensuring its adaptability to the tortuous shape of human colon.The mechanical struc-ture,kinematics and DSP-based control system are discussed; prototype experiments are carried out tovalidate the kinematics model and to show the motion performances.
基金the National Natural Science Foundation of China(Nos.61873257 and U20A20195)the Project of Natural Science Foundation of Liaoning Province(No.2021-MS-033)the Foundation of Millions of Talents Project of the Department of Human Resources and Social Security of Liaoning Province(No.2021921037)。
文摘We proposed a method for shape sensing using a few multicore fiber Bragg grating (FBG) sensors ina single-port continuum surgical robot (CSR). The traditional method of utilizing a forward kinematic model tocalculate the shape of a single-port CSR is limited by the accuracy of the model. If FBG sensors are used forshape sensing, their accuracy will be affected by their number, especially in long and flexible CSRs. A fusionmethod based on an extended Kalman filter (EKF) was proposed to solve this problem. Shape reconstructionwas performed using the CSR forward kinematic model and FBG sensors, and the two results were fused usingan EKF. The CSR reconstruction method adopted the incremental form of the forward kinematic model, whilethe FBG sensor method adopted the discrete arc-segment assumption method. The fusion method can eliminatethe inaccuracy of the kinematic model and obtain more accurate shape reconstruction results using only a smallnumber of FBG sensors. We validated our algorithm through experiments on multiple bending shapes underdifferent load conditions. The results show that our method significantly outperformed the traditional methodsin terms of robustness and effectiveness.
文摘In this paper, the authors present a new control strategy for continuous backbone （continuum） ＂trunk and tentacle＂ robots. Control of this emerging new class of robots has proved difficult due to the inherent complexity of their dynamics. Using a recently established full dynamic model, the authors introduce a new nonlinear model-based control strategy for continuum robots. The approach is applicable to continuum robots which can extend/contract as well as bend throughout their structure. Results are illustrated using the mathematical model of a three-section, six-degree of freedom planar continuum robot.
基金supported by the National Key R&D Program of China(Grant No.2024YFB4707300)the National Natural Science Foundation of China(Grant No.62273289)+3 种基金the Youth Innovation Science and Technology Support Program of Shandong Province(Grant No.2022KJ274)the Shandong Provincial Natural Science Foundation(Grant No.ZR2024MF007)the Fundamental Research Projects of Science&Technology Innovation and Development Plan in Yantai City(Grant No.2024JCYJ050)the Graduate Innovation Foundation of Yantai University。
文摘Continuum robots,characterized by their simplicity,softness,and flexibility,hold significant promise for applications in the field of minimally invasive surgery.Nevertheless,the majority of existing continuum robots are plagued by issues such as a single stiffness property and restricted operation space.To address these challenges,we have engineered a multistiffness nested cooperative magnetic continuum robot grounded in low melting point alloy(LMPA).The core components of this innovative robot are an orientator and a tracker.By integrating neodymium magnets within the orientator,the robot can effectively respond to the external magnetic field,thereby endowing it with a navigation capability.Furthermore,through precisely adjusting the phase and amplitude of the waveforms generated by the signal generator along the X,Y,and Z axes,the Helmholtz coils can produce programmable and controllable magnetic fields.This enables the robot to map out diverse paths,including the typical L-shaped,S-shaped,and U-shaped trajectories.Functionally,when equipped with a shape memory alloy(SMA)gripper,the robot can move steadily and precisely grasp objects within complex passages.This remarkable performance strongly attests to the robot's potential application value in industrial inspection,minimally invasive surgery,and other relevant fields.
基金support from the National Natural Science Foundation of China(No.52205590)the Natural Science Foundation of Jiangsu Province(No.BK20220834)+2 种基金the Start‐up Research Fund of Southeast University(No.RF1028623098)the Taihu Lake Innovation Fund for the School of Future Technology of Southeast Universityin part by SIAT‐CUHK Joint Laboratory of Robotics and Intelligent Systems.
文摘Magnetic continuum robots(MCRs)have garnered substantial attention as a new class of flexible robotic systems capable of navigating complex and confined spaces with remarkable dexterity.By combining continuous,deformable structures with remotely applied magnetic fields,MCRs achieve contactless,remote manipulation,making them well‐suited for medical ap-plications.This review introduces recent advances in MCR research,focusing on design principles,structural configurations,and control strategies.Various MCR designs and structures,including those integrated with permanent magnets,magnetic matter,ferromagnetic sphere,and micro coil,are discussed.Furthermore,different magnetic actuation platforms are intro-duced,and the level of MCR automation is classified based on control strategies.Key intelligent manipulation capabilities of MCRs,including navigation,delivery,printing,grasping,imaging,and sensing are explored.Finally,future development pri-orities and directions are identified to provide insights for advancing intelligent robotic systems.
基金Supported by National Natural Science Foundation of China(Grant Nos.52305003,52175019)National Key R&D Program of China(Grant No.2023YFD2001100)+2 种基金Beijing Natural Science Foundation(Grant No.L222038)Beijing Nova Programme Interdisciplinary Cooperation Project(Grant No.20240484699)Project“Vice President of Science and Technology”of Changping District of Beijing.
文摘The design and analysis of continuum robots have consistently been a prominent research focus in the field of mechanics.However,portable continuum robots with minimal spatial occupancy,which have great potential for applications such as search and rescue,are scarcely available.This paper presents a novel helical-coiled multi-segment flexible continuum robot featuring helical deployment and compact design,with an integrated framework for structural design,kinematic modeling,and experimental validation.The design of the helical-coiled multi-segment flexible continuum robot for unstructured environment detection,including a flexible body,an actuation module,a feed module,and a sensing module,is presented systematically.Kinematic models of both single-and multisegment continuum robots were established based on the constant curvature model to analyze the parameter mapping relationship from the end-effector position and orientation to the driving inputs.Furthermore,the feedforward motion of the robot was examined,and an uncoiling strategy based on S-curve compensation was employed to complete the kinematic analysis.Finally,the accuracy of the kinematic model considering the active uncoiling feed motion was validated through experimental analysis,demonstrating the motion characteristics of the continuum robot.Altogether,this study provides a framework for the design and analysis of helical-coiled continuum robots.
基金funded by the National Natural Science Foundation of China under Grant 51875531“Pioneer”and“Leading Goose”R&D Program of Zhejiang under Grant 2022C02057.
文摘The traditionally articulated manipulator had a single control method,and the limited motion trajectory space was unsuitable for working in an unstructured environment.This paper introduces a control method and optimization for a multijoint manipulator Inspired by snakes'curling and stretching motions.First,we analyze the manipulator’s connection mode and motion planning and propose a new motion method.In addition,we calculated the relevant positions and angles and subdivided the motion of some joints based on the principle of the meta-heuristic algorithm.Ultimately,the manipulator in this mode has a larger workspace and more flexible motion trajectories.The experimental results are consistent with the theoretical analysis,which further proves the feasibility and scalability of the scheme.
