Reversible Adhesive Bio-Toe with Hierarchical Structure Inspired by Gecko

Area of Science:

• Biomimetics and Bionic Engineering
• Adhesion Science
• Robotics and Mechanical Engineering

Background:

• Adhesive animals exhibit sophisticated hierarchical feet and reversible adhesion for locomotion.
• Understanding the structure-function relationship of biological adhesion is crucial for bionic applications.

Purpose of the Study:

• To investigate the reversible adhesion/release behavior and structural properties of gecko toes.
• To design and analyze a hierarchical adhesive bionic toe (bio-toe) for reversible adhesion.

Main Methods:

• Developed a hierarchical adhesive bionic toe with elastic actuators and bionic lamellae.
• Created mathematical and finite element models for nonlinear deformation and adhesive contact.
• Conducted experimental tests to evaluate adhesive behavior and mechanical properties.

Main Results:

• The bio-toe's bending curvature, linear with pressure, allows controllable adaptation to various objects.
• Tabular bio-lamellae achieved 60% contact rate with low squeeze force and ±10° tilt tolerance.
• Upward bending under negative pressure ensured 100% successful release.
• The bio-toe exhibited a high shear adhesion to preload ratio (~12), exceeding existing units.

Conclusions:

• The hierarchical bionic toe demonstrates excellent adaptability, load capacity, and reversible adhesion.
• The bio-toe shows significant potential for integration into robot grippers and wall-climbing robots.
• This bio-inspired adhesive toe has broad applications in space, defense, industry, and daily life.