Mechanism design and experiment verification of a mole-inspired robot burrowing with incisors

With the growing demand for underground resources, traditional drilling equipment faces significant limitations in soil environments. In recent years, bionic burrowing robots have attracted increasing research attention for their potential advantages in miniaturization, adaptability, and low energy consumption, although their development is still in the early exploratory stage. This study presents a mole-inspired robot designed based on the remarkable burrowing capability of the naked mole-rat (Heterocephalus glaber), which uses its incisors to break soil and limbs to propel itself forward. The incisor mechanism of the robot achieves a single-degree-of-freedom (DOF) occlusion via a gear drive and linkage transmission system. To analyze the relationship between the incisor tip force and the servo output torque, a mechanical model based on the principle of virtual work and virtual displacement is established, and its accuracy is validated through physical experiments. The leg mechanism employs a Chebyshev-parallelogram composite linkage configuration to achieve single-DOF forward-backward leg motion. To ensure optimal kinematic performance, the leg kinematics are analyzed, and the leg link lengths are optimized through foot-end trajectory planning. Finally, a prototype was developed and tested in soils with varying moisture contents. The experimental results verify the proposed design methodology and mechanical model, confirming the feasibility and effectiveness of the mole-inspired incisor-limb coordination strategy for autonomous burrowing.