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
Using a generalized quasi-continuum method,we characterize the post-buckling morphologies and energetics of thick multi-walled carbon nanotubes(MWCNTs)under uniaxial compression.Our simulations identify for the first ...Using a generalized quasi-continuum method,we characterize the post-buckling morphologies and energetics of thick multi-walled carbon nanotubes(MWCNTs)under uniaxial compression.Our simulations identify for the first time evolving post-buckling morphologies,ranging from asymmetric periodic rippling to a helical diamond pattern.We attribute the evolving morphologies to the coordinated buckling of the constituent shells.The post-buckling morphologies result in significantly reduced effective moduli that are strongly dependent on the aspect ratio.Our simulation results provide fundamental principles to guide the future design of high-performance,MWCNT-based nanodevices.展开更多
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We gratefully acknowledge support from the National Science Foundation(NSF)grants under Awards Nos.0826841 and 0600642(Clark V.Cooper,program manager)and K.J.H.acknowledges NSF financial support under Grant Nos.CMMI 09-52565 and CMMI 09-06361.
文摘Using a generalized quasi-continuum method,we characterize the post-buckling morphologies and energetics of thick multi-walled carbon nanotubes(MWCNTs)under uniaxial compression.Our simulations identify for the first time evolving post-buckling morphologies,ranging from asymmetric periodic rippling to a helical diamond pattern.We attribute the evolving morphologies to the coordinated buckling of the constituent shells.The post-buckling morphologies result in significantly reduced effective moduli that are strongly dependent on the aspect ratio.Our simulation results provide fundamental principles to guide the future design of high-performance,MWCNT-based nanodevices.
