Study on the Interaction between Soil and the Five-Claw Combination of a Mole Using the Discrete Element Method

Area of Science:

• Biomechanics
• Soil Mechanics
• Robotics

Background:

• Moles possess highly efficient five-clawed hands for digging.
• Detailed understanding of soil-claw interaction is limited.
• This knowledge gap hinders the design of efficient soil-engaging tools.

Purpose of the Study:

• To simulate the soil cutting process of a mole's five-claw combination.
• To analyze the interaction between soil and the five-claw structure.
• To inform the design of novel soil-engaging tools that minimize soil resistance.

Main Methods:

• Utilized the discrete element method (DEM) for simulation.
• Modeled the horizontal movement of the five-claw combination in a soil bin.
• Measured soil forces (draught, vertical) and soil failure (rupture distance ratio) at varying rake angles and speeds.

Main Results:

• Draught and vertical forces showed nonlinear variation with rake angle (10-90°) and linear changes with speed (1-5 m/s).
• Soil rupture distance ratio followed a quadric function of rake angle, with minimal speed dependency.
• The five-claw combination demonstrated a 19.6% lower soil rupture distance ratio than simple blades, indicating reduced soil failure.

Conclusions:

• The five-claw combination effectively reduces soil failure and resistance compared to simple blades.
• Optimal performance, balancing draught and vertical forces, was achieved at a 30° rake angle.
• Findings provide insights for designing biomimetic, low-resistance soil-engaging tools.