Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko

The agile locomotion of adhesive animals is mainly attributed to their sophisticated hierarchical feet and reversible adhesion motility. Their structure–function relationship is an urgent issue to be solved to understand biologic adhesive systems and the design of bionic applications. In this study,...

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Main Authors: Liuwei Wang, Zhouyi Wang, Bingcheng Wang, Qingsong Yuan, Zhiyuan Weng, Zhendong Dai
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:Biomimetics
Subjects:
Online Access:https://www.mdpi.com/2313-7673/8/1/40
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author Liuwei Wang
Zhouyi Wang
Bingcheng Wang
Qingsong Yuan
Zhiyuan Weng
Zhendong Dai
author_facet Liuwei Wang
Zhouyi Wang
Bingcheng Wang
Qingsong Yuan
Zhiyuan Weng
Zhendong Dai
author_sort Liuwei Wang
collection DOAJ
description The agile locomotion of adhesive animals is mainly attributed to their sophisticated hierarchical feet and reversible adhesion motility. Their structure–function relationship is an urgent issue to be solved to understand biologic adhesive systems and the design of bionic applications. In this study, the reversible adhesion/release behavior and structural properties of gecko toes were investigated, and a hierarchical adhesive bionic toe (bio-toe) consisting of an upper elastic actuator as the supporting/driving layer and lower bionic lamellae (bio-lamellae) as the adhesive layer was designed, which can adhere to and release from targets reversibly when driven by bi-directional pressure. A mathematical model of the nonlinear deformation and a finite element model of the adhesive contact of the bio-toe were developed. Meanwhile, combined with experimental tests, the effects of the structure and actuation on the adhesive behavior and mechanical properties of the bio-toe were investigated. The research found that (1) the bending curvature of the bio-toe, which is approximately linear with pressure, enables the bio-toe to adapt to a wide range of objects controllably; (2) the tabular bio-lamella could achieve a contact rate of 60% with a low squeeze contact of less than 0.5 N despite a ±10° tilt in contact posture; (3) the upward bending of the bio-toe under negative pressure provided sufficient rebounding force for a 100% success rate of release; (4) the ratio of shear adhesion force to preload of the bio-toe with tabular bio-lamellae reaches approximately 12, which is higher than that of most existing adhesion units and frictional gripping units. The bio-toe shows good adaptability, load capacity, and reversibility of adhesion when applied as the basic adhesive unit in a robot gripper and wall-climbing robot. Finally, the proposed reversible adhesive bio-toe with a hierarchical structure has great potential for application in space, defense, industry, and daily life.
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spelling doaj.art-3e24b8119c684f6aa6520dba33e5df422023-11-17T09:49:25ZengMDPI AGBiomimetics2313-76732023-01-01814010.3390/biomimetics8010040Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by GeckoLiuwei Wang0Zhouyi Wang1Bingcheng Wang2Qingsong Yuan3Zhiyuan Weng4Zhendong Dai5College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaCollege of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaCollege of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaCollege of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaCollege of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaCollege of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaThe agile locomotion of adhesive animals is mainly attributed to their sophisticated hierarchical feet and reversible adhesion motility. Their structure–function relationship is an urgent issue to be solved to understand biologic adhesive systems and the design of bionic applications. In this study, the reversible adhesion/release behavior and structural properties of gecko toes were investigated, and a hierarchical adhesive bionic toe (bio-toe) consisting of an upper elastic actuator as the supporting/driving layer and lower bionic lamellae (bio-lamellae) as the adhesive layer was designed, which can adhere to and release from targets reversibly when driven by bi-directional pressure. A mathematical model of the nonlinear deformation and a finite element model of the adhesive contact of the bio-toe were developed. Meanwhile, combined with experimental tests, the effects of the structure and actuation on the adhesive behavior and mechanical properties of the bio-toe were investigated. The research found that (1) the bending curvature of the bio-toe, which is approximately linear with pressure, enables the bio-toe to adapt to a wide range of objects controllably; (2) the tabular bio-lamella could achieve a contact rate of 60% with a low squeeze contact of less than 0.5 N despite a ±10° tilt in contact posture; (3) the upward bending of the bio-toe under negative pressure provided sufficient rebounding force for a 100% success rate of release; (4) the ratio of shear adhesion force to preload of the bio-toe with tabular bio-lamellae reaches approximately 12, which is higher than that of most existing adhesion units and frictional gripping units. The bio-toe shows good adaptability, load capacity, and reversibility of adhesion when applied as the basic adhesive unit in a robot gripper and wall-climbing robot. Finally, the proposed reversible adhesive bio-toe with a hierarchical structure has great potential for application in space, defense, industry, and daily life.https://www.mdpi.com/2313-7673/8/1/40bio-toereversible adhesionhierarchical structuregecko
spellingShingle Liuwei Wang
Zhouyi Wang
Bingcheng Wang
Qingsong Yuan
Zhiyuan Weng
Zhendong Dai
Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko
Biomimetics
bio-toe
reversible adhesion
hierarchical structure
gecko
title Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko
title_full Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko
title_fullStr Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko
title_full_unstemmed Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko
title_short Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko
title_sort reversible adhesive bio toe with hierarchical structure inspired by gecko
topic bio-toe
reversible adhesion
hierarchical structure
gecko
url https://www.mdpi.com/2313-7673/8/1/40
work_keys_str_mv AT liuweiwang reversibleadhesivebiotoewithhierarchicalstructureinspiredbygecko
AT zhouyiwang reversibleadhesivebiotoewithhierarchicalstructureinspiredbygecko
AT bingchengwang reversibleadhesivebiotoewithhierarchicalstructureinspiredbygecko
AT qingsongyuan reversibleadhesivebiotoewithhierarchicalstructureinspiredbygecko
AT zhiyuanweng reversibleadhesivebiotoewithhierarchicalstructureinspiredbygecko
AT zhendongdai reversibleadhesivebiotoewithhierarchicalstructureinspiredbygecko