Scientists at the University of Bristol’s Bristol Robotics Laboratory revealed the development of a robot that promises to revolutionise mobility and exploration.

The Tetraflex, a tetrahedron-shaped robot equipped with flexible piping, is capable of navigating the most challenging terrains and transporting delicate cargo, opening up a world of possibilities for applications ranging from disaster response to ecological surveying.

“The robot is composed of soft struts connected by rigid nodes. Each strut is formed of an airtight rubber bellow and the length of the strut can be controlled by varying the air pressure within the bellow,” explained Peter Wharton of the School of Engineering, Mathematics and Technology at the University of Bristol, and lead author of the study. 

"Higher pressures cause the bellow to extend, and lower pressures cause it to contract. By controlling the pressure in each bellow simultaneously we can control the robot shape and size change,” he added in a statement.

What truly sets Tetraflex apart is its ability to locomote in a variety of ways, including rolling and crawling, thanks to the dynamic control of its soft struts. This adaptability makes it suitable for manoeuvring through confined environments, such as disaster-stricken areas, conducting oil rig inspections, or exploring extraterrestrial terrain. 

The Tetraflex also possesses the capability to encase and transport fragile payloads, potentially aiding ecological surveys or nuclear decommissioning. 

Pioneering versatility in robotics

The Tetraflex's soft-strut design is the key to its extraordinary versatility. The Tetraflex assumes different shapes and sizes by altering the lengths of its struts, facilitating rolling, crawling, or even enveloping and transporting objects.

“I would say that these capabilities are a natural consequence of working with such a versatile structure and we hope that other interesting capabilities can be developed in the future,” saids Wharton.

"The most exciting aspect of this study for me is the versatility of Tetraflex and how we might be able to use these robots to explore challenging terrain and achieve tasks in areas humans cannot access. The multiple gaits available to Tetraflex and object transport capability show this versatility well."

The Tetraflex's versatility was recently demonstrated when the team entered an earlier version of the robot in the RoboSoft 2022 Locomotion Competition in Edinburgh, where it secured third place. The robot gracefully showcased its ability to move over sandy terrain, traverse small gaps, and navigate around obstacles. 

Tetraflex, the shape-changing multipurpose robot. Image: Peter Wharton

The road ahead for Tetraflex

Having explored the locomotion and object transport capabilities of Tetraflex, the research team now plans to take it to the next level by integrating machine learning algorithms. These algorithms will empower Tetraflex to further refine its movement patterns and optimise existing ones.

"There could be some really creative and effective ways of moving around or interacting with the environment that we haven't yet discovered," said Wharton. 

The findings of the research team can be found in this paper published in IEEE Robotics and Automation Letters.