Air pressure makes the tentacles bend
A rigid robot changes position at joints: motors turn hinges, and the resulting force is concentrated where its hard parts meet an object. A pneumatic soft robot moves differently. Pneumatic means powered by pressurized air. Air enters channels inside a flexible silicone body; as a chamber expands, it pushes the material into a curve. Arrange the chambers so one side lengthens more than the other, and the whole finger curls.
Because the silicone itself bends, the gripper has no stiff hinge that must line up with a coral branch. Its tentacles can conform as they make contact, spreading the touch across a larger, softer area rather than pinching at a single point. That difference matters for coral, whose delicate structures can be damaged by a hard, concentrated grip.
Inspired by the way jellyfish move
The design takes a cue from jellyfish muscles, which produce movement through flexible tissue rather than rigid skeletal joints. In the robotic version, air pressure supplies the actuation—the force that causes motion—and the shape of the internal air chambers determines how the tentacle bends. Adjusting pressure lets the gripper curl around an irregular form without requiring a separate mechanical hinge for every change in direction.
This approach trades the precise, forceful control of a rigid arm for compliance: the device can give and adapt when it meets an uneven surface. For fragile coral, that is the point. The robot’s ability to wrap around a branch is useful only if its contact stays gentle enough not to crush it.
