Many studies have examined the design,fabrication and characteristics of gecko-inspired adhesives,but applied research on gecko-inspired surfaces in humanoid dexterous hands is relatively scarce.Here,a wedged slanted ...Many studies have examined the design,fabrication and characteristics of gecko-inspired adhesives,but applied research on gecko-inspired surfaces in humanoid dexterous hands is relatively scarce.Here,a wedged slanted structure with a curved substrate suitable for humanoid dexterous fingers was designed and manufactured via ultraprecision machining and replica molding.The adhesion and friction properties of the wedged slanted structure show obvious anisotropic characteristics in the gripping and releasing directions,and the influence of structural parameters and motion parameters on the adhesion and friction was systematically studied.The humanoid dexterous fingers with gecko-inspired surfaces greatly increased the grasping force limit(increase to 4.02 times)based on the grasping of measuring cups with different volumes of water and improved the grasping stability based on the picking up of smooth steel balls of different diameters.This study shows that this process,based on ultraprecision machining and replica molding,is a green,high-efficiency,and low-cost method to fabricate large-area biomimetic surfaces that has potential applications in dexterous humanoid hands to improve grasping ability,stability and adaptability.展开更多
Soft grippers are key manipulation tools for robotics and end effectors for securely grasping objects of various shapes and sizes on demand.However,critical challenges,including self-adaptive grasping to curved surfac...Soft grippers are key manipulation tools for robotics and end effectors for securely grasping objects of various shapes and sizes on demand.However,critical challenges,including self-adaptive grasping to curved surfaces and monitoring the contact state,remain.Here,a gecko-inspired curved flexible surface adaptive gripper(CSAG),which consists of a variable-bending pneumatic actuator,a triboelectric sensor(T-sensor),and a gecko-inspired microwedge adhesive,is proposed.The contact-sensitive triboelectric sensor can sense the critical contact state of objects to trigger a variable-bending pneumatic actuator with sufficient shear loading for the geckoinspired microwedge adhesive.A set of experiments are implemented to verify that the proposed soft gripper can adaptively grasp diverse curved objects,including quail eggs,cans,shuttlecocks,expanding objects with varying volumes(such as balloons,the range of diameter variation is 20-115 mm),and spherical acrylic cylinders(20-40 mm)at low pressures(20-25 kPa)with a maximum weight of 37 g.Additionally,the tracking and grasping of a moving ball is demonstrated via a mean-shift algorithm based on image recognition coupled with coordination tracking of a robotic arm.The soft gripper provides a new paradigm to achieve switchable grasping of curved flexible surfaces,which broadens future applications for versatile unstructured human‒robot‒environment interactions,such as adaptive robots and medical devices.展开更多
Geckos can efficiently navigate complex terrains due to their multi-level adhesive system that is present on their toes.The setae are responsible for the gecko’s extraordinary adhesion and have garnered wide attentio...Geckos can efficiently navigate complex terrains due to their multi-level adhesive system that is present on their toes.The setae are responsible for the gecko’s extraordinary adhesion and have garnered wide attention from the scientific community.The majority of the reported works in the literature that have dealt with the peeling models mainly focus on the gecko hierarchical adhesive system,with limited attention given to investigating the influence of gecko toe structure on the detachment.Along these lines,to gain a deeper understanding of the rapid and effortless detachment abilities of gecko toes,the peeling behavior of gecko toes on vertical surfaces was primarily investigated in this work.More specifically,the detachment time of a single toe on a smooth acrylic plate was measured to be 0.41±0.21 s.Moreover,it was observed that the toe assumed a"U"-shaped structure upon complete detachment.Additionally,Finite Element Analysis(FEA)models for three different types of gecko toes were developed to simulate both the displacement-peel and the moment-peel modes.Increasing the segmentation of the adhesive layer led to a gradual decrease in the resultant force,as well as the normal and tangential components.Lastly,a gecko-inspired toe model was constructed and powered by Shape Memory Alloy(SMA).A systematic comparison between the vertical drag separation and the outward flip separation was also conducted.From our analysis,it was clearly demonstrated that outward peel separation significantly necessitated the reduction of the peeling force,thus confirming the advantageous nature of the outward motion in gecko toe detachment.Our data not only contribute to a deeper understanding of the gecko detachment behavior but also offer valuable insights for the advancement of the wall-climbing robot feet.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2018YFB1305300)the National Natural Science Foundation of China(Grant Nos.61733001,61873039,U1713215,U1913211,and U2013602)the China Postdoctoral Science Foundation(Grant No.2021M690017)。
文摘Many studies have examined the design,fabrication and characteristics of gecko-inspired adhesives,but applied research on gecko-inspired surfaces in humanoid dexterous hands is relatively scarce.Here,a wedged slanted structure with a curved substrate suitable for humanoid dexterous fingers was designed and manufactured via ultraprecision machining and replica molding.The adhesion and friction properties of the wedged slanted structure show obvious anisotropic characteristics in the gripping and releasing directions,and the influence of structural parameters and motion parameters on the adhesion and friction was systematically studied.The humanoid dexterous fingers with gecko-inspired surfaces greatly increased the grasping force limit(increase to 4.02 times)based on the grasping of measuring cups with different volumes of water and improved the grasping stability based on the picking up of smooth steel balls of different diameters.This study shows that this process,based on ultraprecision machining and replica molding,is a green,high-efficiency,and low-cost method to fabricate large-area biomimetic surfaces that has potential applications in dexterous humanoid hands to improve grasping ability,stability and adaptability.
基金supported by the National Natural Science Foundation of China(No.52075264).
文摘Soft grippers are key manipulation tools for robotics and end effectors for securely grasping objects of various shapes and sizes on demand.However,critical challenges,including self-adaptive grasping to curved surfaces and monitoring the contact state,remain.Here,a gecko-inspired curved flexible surface adaptive gripper(CSAG),which consists of a variable-bending pneumatic actuator,a triboelectric sensor(T-sensor),and a gecko-inspired microwedge adhesive,is proposed.The contact-sensitive triboelectric sensor can sense the critical contact state of objects to trigger a variable-bending pneumatic actuator with sufficient shear loading for the geckoinspired microwedge adhesive.A set of experiments are implemented to verify that the proposed soft gripper can adaptively grasp diverse curved objects,including quail eggs,cans,shuttlecocks,expanding objects with varying volumes(such as balloons,the range of diameter variation is 20-115 mm),and spherical acrylic cylinders(20-40 mm)at low pressures(20-25 kPa)with a maximum weight of 37 g.Additionally,the tracking and grasping of a moving ball is demonstrated via a mean-shift algorithm based on image recognition coupled with coordination tracking of a robotic arm.The soft gripper provides a new paradigm to achieve switchable grasping of curved flexible surfaces,which broadens future applications for versatile unstructured human‒robot‒environment interactions,such as adaptive robots and medical devices.
基金Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structures,1005-IZD23002-25Aihong Ji,National Natural Science Foundation of China,51861135306,Aihong Ji,51875281Aihong Ji,Nanjing University of Aeronautics and Astronautics Doctoral Student Short-Term Overseas Visiting Program,230304DF05,Qingfei Han.
文摘Geckos can efficiently navigate complex terrains due to their multi-level adhesive system that is present on their toes.The setae are responsible for the gecko’s extraordinary adhesion and have garnered wide attention from the scientific community.The majority of the reported works in the literature that have dealt with the peeling models mainly focus on the gecko hierarchical adhesive system,with limited attention given to investigating the influence of gecko toe structure on the detachment.Along these lines,to gain a deeper understanding of the rapid and effortless detachment abilities of gecko toes,the peeling behavior of gecko toes on vertical surfaces was primarily investigated in this work.More specifically,the detachment time of a single toe on a smooth acrylic plate was measured to be 0.41±0.21 s.Moreover,it was observed that the toe assumed a"U"-shaped structure upon complete detachment.Additionally,Finite Element Analysis(FEA)models for three different types of gecko toes were developed to simulate both the displacement-peel and the moment-peel modes.Increasing the segmentation of the adhesive layer led to a gradual decrease in the resultant force,as well as the normal and tangential components.Lastly,a gecko-inspired toe model was constructed and powered by Shape Memory Alloy(SMA).A systematic comparison between the vertical drag separation and the outward flip separation was also conducted.From our analysis,it was clearly demonstrated that outward peel separation significantly necessitated the reduction of the peeling force,thus confirming the advantageous nature of the outward motion in gecko toe detachment.Our data not only contribute to a deeper understanding of the gecko detachment behavior but also offer valuable insights for the advancement of the wall-climbing robot feet.
