Duke University engineers have developed a completely soft dragonfly-shaped robot designed to slide across the water’s surface and react to environmental conditions. The robot, called DraBot, is totally free of electronics and reacts to environmental conditions such as pH, temperature or the presence of oil. The researchers believe that the proof-of-principle demonstration unit may be the precursor to a more advanced, long-range autonomous environmental robot capable of monitoring a range of problems.
The project researchers started by designing a soft robot based on a fly. After several iterations, the researchers established themselves in the form of a dragonfly designed with a network of internal microchannels allowing it to be controlled by means of air pressure. The robot’s body is about 2.25 inches long and 1.4 inches wide.
The robot’s body was created by pouring silicon into an aluminum mold and then roasting it. Internal channels were created using smooth lithography and were connected with flexible silicone tubes. The researchers were challenged to make DraBot respond to air pressure controls over long distances using automatic actuators without any electronic devices.
DraBot works by controlling the air pressure that enters your wings. The microchannel squeezes air into the front wings, from where it escapes through a series of holes aimed at the rear wings. When the rear wings are lowered, the air flow is blocked and the DraBot remains stationary. When both wings are raised, DraBot moves forward.
The team also designed balloon actuators under each rear wing close to the robot’s body. When they are inflated, the balloons cause the wings to move upwards, allowing the controllers to tell the robot where to go. The wings are painted with a self-curing hydrogel that makes them sensitive to changes in the pH of the water.
When the water is acidic, a front wing merges with the rear wing, causing the robot to rotate in a circle instead of traveling in a straight line. When the pH returns to normal, the fused wings separate and the bot responds to commands. The researchers also placed sponges on the robot that will absorb the oil and change color, indicating its presence. DraBot’s wings also change from red to yellow if the water is too hot.