Generally speaking, robotic grippers are designed to handle specific objects. This is ideal for assembly lines, where every object the robot interacts with is exactly the same size and shape. But what if a more flexible solution is required? What if a robot needs to sort through a random pile of junk — like, say, a conveyor belt ferrying rubbish into a recycling plant? In such a scenario, a single-purpose gripper wouldn’t do the trick.
Enter: the FlexShapeGripper from Festo. Inspired by the manner in which a chameleon’s tongue grabs its prey, the gripper uses a soft, fluid-filled silicone bag in lieu of a mechanical claw. This allows it to grab a wide range of different objects by doing little more than changing the volume of fluid inside the gripper’s tip. Check out the video below to see it in action:
The gripper consists of two chambers: an interior one filled with compressed air, and a water-filled exterior chamber that encloses it. During the gripping procedure, the robotic arm guides the gripper toward the object until it touches the silicone cap. At this point, a pneumatic piston moves back and vents the internal air chamber, causing the water-filled silicone tip to curl inward. While this happens, the handling system gently guides the gripper further toward the object, allowing the silicone cap to better wrap itself around a the object, resulting in a tighter fit.
This approach has a number of advantages. First of all, the silicone tip is elastic enough that it can adapt to fit a wide range of different geometries, allowing the gripper to work regardless of an object’s shape, and even to pick up multiple objects at once. Second, the high-static friction of the silicone creates a strong, slip-free holding force. Once an object is in the robot’s clutches, no additional energy is required to maintain the grip.
Fitted with such a novel extremity, a robot arm could pick up nearly anything: keys, credit cards, ball bearings — you name it. As long as the object’s surface isn’t too broad for the gripper head to wrap around, the FlexShapeGripper should be able to snag it.
Pretty brilliant, right?