What Inspired the Concept?
The research team at KAIST, led by Professor Hyun Myung, had two key aims:
- To find a way to explore areas of potential new energy sources. Coalbed methane, buried methane gas, and rare earth elements have until now required highly advanced drilling technologies, and this has stood in the way of such materials providing an economically-viable replacement to existing energy sources (such as petroleum and coal).
- To enable exploration and sampling in extreme regions of space. To achieve this, the team at KAIST took inspiration from two remarkable features found in the African mole-rat and the European mole.
The African mole-rat’s teeth have immense crushing power. So much so that the animal has the ability to dig a hole with 48 times more force than its body weight. Meanwhile, the European mole’s shoulder blade (i.e. its scapula—see diagram below) enables it to create powerful rotational force required for debris removal and soil excavation.
The research team hoped that, by mimicking these mammalian characteristics, they could create a robot with the drilling power and movement required to work quickly, accurately, and economically in extreme environments.
A diagram that depicts the biological structure of the European mole and the Korea Advanced Institute of Science and Technology’s (KAIST) researchers biomimetic design of their robot’s ‘forelimbs’. Image Credit: KAIST.
What Does the Mole-Inspired Robot Consist Of?
According to the research team, the Mole-bot, at only 25 centimetres wide, 84 centimetres long, and weighing only 26 kilograms, can excavate three times faster than conventional models, all while achieving six times higher directional accuracy. This has been made possible by its three mole-inspired parts, covered below.
An Expandable Drilling Part
To achieve an excavation tool with powerful torque, the robot’s drill imitates the crushing power and chiselling ability of a mole-rat's teeth. In addition, the drilling part has been carefully designed so that it doesn’t collide with the robot’s forelimbs, enabling both parts to work concurrently.
Two Powerful Forelimbs
The forelimbs are for the robot to remove debris during the drilling process. The Mole-bot’s forelimbs have an embedded muscle feature that mimics the mole’s scapula. This enables the robot to convert linear motion into powerful rotational force and excavate soil at speed.
An Elongated Waist
The waist of the robot was designed to enable it to change direction by 360 degrees. The ability to be inclinable on all sides enables the robot to achieve directional drilling (i.e. non-vertical drilling) even in confined spaces.
The Engineering Potential of the Development
Its many above features are just the beginning of KAIST’s engineering accomplishments. The research team has also developed and applied new sensor systems and algorithms to enable them to identify the mole-inspired robot’s position and orientation. The system uses graph-based, three-dimensional SLAM (simultaneous localisation and mapping) technology that is aligned with the Earth’s magnetic field sequence. The result is a robot that can achieve 3D autonomous navigation underground.
A close-up of the biomimetic Mole-bot, designed to explore space and underground resources. Image Credit: KAIST.
Indeed, the development by KAIST’s research team is an exciting one for unmanned exploration in the underground environment. Previous attempts in these challenging environments have been unsuccessful: consider that wireless communication is insufficient due to the surrounding rocks and soil, and vision and laser sensors are hampered by the narrow and dark environment. What’s more, conventional drilling processes use environmentally-unfriendly mud compounds to remove debris. The Mole-bot saves costs on labour, requires no additional pipelines, and is kinder to the environment.
The Korea Advanced Institute of Science and Technology research team claims that the Mole-bot will be able to explore new resources more efficiently while also delivering economic efficiency. According to Technavio’s market research, the directional drilling market is expected to grow by $4.36 billion by 2023. With such demand, the development of technology like the Mole-bot, which can help to expand the use of untapped resources, is vital and could have a very positive impact on the robotics market.