WASHINGTON — Harvard engineers developed a tiny robot with sticky feet that could climb up, down and all around in narrow, complex space.
The study published on Wednesday in the journal Science Robotics reported the 1.48-gram micro-robot with electro-adhesive foot pads, origami ankle joints, and specially engineered walking gait which allow it to climb on vertical and upside-down conductive surfaces like the inside walls of a commercial jet engine.
“They could one day enable non-invasive inspection of hard-to-reach areas of large machines, saving companies time and money and making those machines safer,” said the study’s first author Sebastien de Rivaz, a former Research Fellow at Harvard who now works at Apple.
The researchers equipped the foot pad with a polyimide-insulated copper electrode to generate electrostatic forces between the pads and the conductive surface.
The foot pads can be easily released and re-engaged by switching the electric field on and off, which operates at a voltage similar to that required to move the robot’s legs, enough to keep the robot from sliding down or falling off, according to the study.
Also, the pads are flexible, allowing the robot to climb on curved or uneven surfaces.
They also created origami-like ankle joints that can rotate in three dimensions to compensate for rotations of its legs as it walks, ensuring its orientation.
The robot has a special walking pattern with three foot pads always touching the surface during the leg-swinging.
Tested on vertical and inverted surfaces, it was able to achieve more than 100 steps in a row without detaching, according to the study.
The robot can also walk around a curved, inverted section in a jet engine. A jet engine has about 25,000 individual parts and cannot be inspected without taking the machine apart.
The research is aimed to build an army of robots capable of climbing inside parts of jet engines that are inaccessible to human workers.
In addition, because the robot’s payload capacity is greater than its own weight, making it possible to carry a power supply, electronics and sensors to inspect its environments.
It is the “first and most convincing step” showing the possibility of a centimeter-scale climbing robot and it could be used in the future to “explore any sort of infrastructure, including buildings, pipes, engines, generators,” said the study’s corresponding author Robert Wood at Harvard University.