DraBot Is a Soft Robotic Dragonfly That Can Monitor the Environment

Electronics-free robot uses air pressure, microarchitectures and self-healing hydrogels to watch for changes in pH, temperature and oil.

Cabe Atwell
3 years agoRobotics
The DraBot monitors changes in pH levels, temperatures and oils using air pressure, microarchitectures and self-healing hydrogels. (📷: Duke University)

Engineers at Duke University have developed a soft robotic dragonfly, void of internal electronics capable of skimming on water and monitoring environmental conditions, such as pH levels, temperature, and the presence of oil. The robot’s functions could be the foundation to develop more advanced, autonomous robots designed to monitor changes in the environment. Soft robotics is an emerging research area that focuses on innovative designs using compliant materials, such as hydrogels and elastomers. These soft materials allow robots to explore constrained spaces where traditional robots can’t navigate efficiently.

The engineers built the 2.25-inch long DraBot (Dragonfly Robot) by pouring silicon into an aluminum mold, then baking it. Soft lithography is then used to create interior air channels connected to flexible tubing. The robot functions by pumping air pressure into its wings, where microchannels then carry that air to the front part of the wing. The air then escapes through micro-holes at the rear edge of each wing. If both wings are down, the airflow is blocked, and the robot remains stationary, but if the wings are up, the air pressure moves the robot forward. Under each of the back wings are balloon-based actuators, and when they are inflated, the wings curl into an upward position. By changing the amount of air pressure in each actuator, the engineers can tell the robot where to move.

The sensing properties come in the form of the hydrogel the engineers used to paint the DraBot’s wings, which is responsive to changes in the water’s pH levels. If the water becomes acidic, one side of the front wings will fuse to the back, causing the robot to fly in circles. When the pH returns to normal, then the wings will unfuse, and the robot will return to routine flight. The hydrogel also has repair capabilities, so if the robot becomes damaged, it can then self-repair and resume its mission.

The engineers also doped the wings with a temperature-sensitive material, which changes color in the presence of oil as it interacts with the wings and turns red to yellow when the temperature rises. As mentioned earlier, the engineers created the DraBot as a proof-of-concept and plan to outfit future revisions with a propellant to untether the robot from its flexible tubing. They also plan to outfit the robot with miniature cameras and solid-state hardware for more precise data collection.

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