Micro-robots inspired by the insect world

These tiny marvels, mirroring a mini-bug and a water strider, represent the pinnacle of micro-robotic development in terms of size, weight, and speed. The advent of such robots opens up new horizons for their application in fields ranging from artificial pollination and search and rescue operations to environmental surveillance, micro-manufacturing, and robot-assisted medical procedures.

Published in the Proceedings of the IEEE Robotics and Automation Society's International Conference on Intelligent Robots and Systems, the findings highlight the robots' impressive specifications. The mini-bug tips the scales at a mere eight milligrams, while the water strider boasts a weight of 55 milligrams. Both robots are capable of speeds up to six millimetres per second, a notable achievement in the micro-robotic landscape, albeit still trailing behind their natural counterparts. For context, an ant, weighing up to five milligrams, can scurry at nearly a meter per second.

Conor Trygstad, a PhD candidate in the School of Mechanical and Materials Engineering and the study's lead author, emphasises the significance of the robots' miniature actuators as being the smallest and quickest of their kind, and are the result of innovative fabrication techniques that have scaled them down to less than a milligram. Néstor O. Pérez-Arancibia, Flaherty Associate Professor in Engineering and project leader, underlines the actuators' pivotal role, utilising shape memory alloys that shift shape upon heating, thereby propelling the robots without traditional motors or moving parts.

This technology leverages shape memory alloys' capacity to remember and revert to their original form. Unlike conventional robotics movement, which relies on bulkier mechanisms, the WSU team's robots employ two slender wires of a shape memory alloy. These wires, merely 1/1000 of an inch in diameter, can be heated and cooled swiftly with minimal electrical current, enabling the robots to mimic biological motion with their fins or legs at rates up to 40 times per second. In early testing, the actuators demonstrated the ability to lift over 150 times their own weight.

The minimal power requirements of the shape memory alloy (SMA) system mark a departure from the energy demands of traditional robotic mobility solutions. This efficiency could herald new possibilities for micro-robotic applications where power conservation is crucial.

Trygstad observed water striders' efficient rowing movements, which his robotic counterpart seeks to emulate. The team is not only looking to refine the water strider robot's motion for enhanced speed but also exploring the development of robots capable of navigating both atop and just below water surfaces. The goal is to achieve full autonomy for these robots, potentially through the use of tiny batteries or catalytic combustion, freeing them from tethered power sources.

The inspiration drawn from animals is prevalent in many areas of industry with various instances of the natural world serving as a muse for technological innovation.

From the development octopus-inspired camouflage or gloves, to spiders inspiring microelectronic production and intelligence gathering ‘dogs’, these stories highlight a trend of harnessing biological principles to solve engineering challenges. Such biomimicry not only enriches our technological repertoire but also fosters a deeper appreciation for the natural world's ingenuity.

As micro-robotics continues to advance, it's evident that even the smallest of creatures in our ecosystems are inspiring some of the biggest leaps in engineering and technology.