Bio-Inspired Mole-Like Drilling Robot

New natural resources, such rare earth elements, are being explored due to the development of electronic instruments. Also, new drilling systems for planetary exploration are in demand. Current technologies of drilling are bulky, not suitable for shallow depths and soft grounds, and remove excavated soil by non-ecologically friendly ways. One way to overcome the limitations of previous systems is to use mechanisms that mimic animals with excavation habits.

A recent paper suggests a robot which simulates the structure and behaviour of a mole. The most useful properties of two species are used together: a mole-rat’s teeth and jaw and a European mole’s forelimb structure.

Image credit: Junseok Lee, Christian Tirtawardhana, and Hyun Myung, arXiv:2008.12229

An expandable drill bit mimics the mole-rat incisors and jaw. A wheel mechanism allows continuous drilling simultaneously with the expanding of the blades. The excavated soil is being removed by a mechanism inspired by the anatomy of humeral rotation diggers.

Interests in exploration of new energy resources are increasing due to the exhaustion of existing resources. To explore new energy sources, various studies have been conducted to improve the drilling performance of drilling equipment for deep and strong ground. However, with better performance, the modern drilling equipment is bulky and, furthermore, has become inconvenient in both installation and operation, for it takes complex procedures for complex terrains. Moreover, environmental issues are also a concern because of the excessive use of mud and slurry to remove excavated soil. To overcome these limitations, a mechanism that combines an expandable drill bit and link structure to simulate the function of the teeth and forelimbs of a mole is proposed. In this paper, the proposed expandable drill bit simplifies the complexity and high number of degrees of freedom of the animal head. In addition, a debris removal mechanism mimicking a shoulder structure and forefoot movement is proposed. For efficient debris removal, the proposed mechanism enables the simultaneous rotation and expanding/folding motions of the drill bit by using a single actuator. The performance of the proposed system is evaluated by dynamic simulations and experiments.