From slow-motion machines inspired by sloths to others that explode from the water and soar into the air like flying fish, robots mimic the behavior of real-world creatures. Potentially interesting when monitoring the environment. A new Duke University innovation is another interesting example, chasing a dragonfly gliding over water and checking for oil spills, high acidity and other anomalies, and doing so without any electronic devices on board.
DraBot, as it has been named, follows several other nature-inspired air-powered robots, including runners like cheetahs, turtles walk and swimming like jellyfish.
Just 2.25 inches (5.7 cm) long, this soft robot has an internal network of microchannels connected to a flexible silicone tube, pumping air into its wings to escape through holes in the back to push robot on water. The inflatable actuator can be used to lower the blades later on, in case the airflow is blocked and the DraBot remains at rest. In this way, the team can control which wing goes up and down, and thus the direction of the robot.
“Getting DraBot to respond to long-distance air pressure controls using only self-actuators without any electronics is very difficult,” said team member Ung Hyun Ko. “That is definitely the most challenging part.”
To fit their new robot for environmental monitoring, the team turned to using a self-healing hydrogel they had created in a previous research project. The material reacts to changes in acidity by forming new bonds within itself, which are then reversed when the pH returns to normal. The team coated DraBot’s wings with hydrogels, making one fore and one rear fuse as it enters highly acidic water.
This means that when the DraBot encounters a higher pH, it spins in circles instead of moving in a straight line. When these pH levels normalize, the fused wings split off and the DraBot can be properly controlled again.
The team also incorporated sponges into DraBot and doped its wings with materials that react with temperature. As it moves through the water and meets oil on its surface, the sponge soaks up the oil and changes color. When the water temperature is abnormally high, the wing changes from red to yellow. This can allow DraBot to glide over water and both detect and clean off oil spills, while also showing signs of bleaching of coral reefs or blooming algae through changes in water temperature. Meanwhile, high pH levels can also reveal acidified water threatens marine life, including coral reefs.
From here on, the team hopes to make some improvements to DraBot. Mounting it with an onboard pusher would eliminate the need for silicon tubes, while it imagined adding cameras and sensors to further expand its environmental monitoring capabilities.
“Instead of using air pressure to control the wings, I can imagine using some kind of synthetic biology to generate energy,” said team member Shyni Varghese. “It’s a completely different field from the one I work in, so we’ll have to talk to some potential contributors to see what might happen. But it’s part of the joy of working on an interdisciplinary project like this.
The video below shows DraBot in action, while the research is published in the journal Advanced intelligent system.
Soft robot “DraBot” Looking for environmental problems
Source: Duke University