Rotating Water Rings Give Vacuum Grippers Spider-Man-Like Suction on Even Rough Surfaces
Capable of holding researchers as they climb a rough wall, the "zero-pressure difference" grippers show real potential.
Researchers from Zhejiang University have demonstrated a zero-pressure difference (ZPD) wall-climbing robot, designed to provide Spider-Man-like adhesion to even rough and texture surfaces.
Using vacuum suction to adhere a robot to a surface isn't a new concept, but it is one which has several limitations — the biggest of which is that it only really works on very smooth surfaces, such as glass. When the same system is used to climb a rough surface, the vacuum leaks out where a seal cannot be made - and the robot plummets to the ground.
The zero-pressure difference (ZPD) system developed at Zhejiang University claims to solve that problem. By place rings of water which rotate at high speeds between the surface and the suction cup, the gaps between the cup and a texture surface are filled — and, the researchers say, the robot can maintain its grip. The result is a system which is said to be more energy efficient, smaller, and lighter than traditional vacuum suction graspers yet also suited to a wider variety of surfaces.
"There are many applications of our design, but we think the wall-climbing robot will be the most useful," says Xin Li, who co-authored the paper with Kaige Shi. "Compared to other wall-climbing robots, the robot with our ZPD-based suction unit achieves surprising improvement in performance."
The pair created three proof-of-concept robot systems to demonstrate the design: A robotic capable of gripping and manipulating objects; a hexapod wall-climbing robot; and, impressively, a wall-climbing device inspired by Spider-Man's abilities.
There is only one real drawback at present: using the system requires a lot of water. "The next step in this research is to cut down the water consumption," Li explains. "If the water consumption can be reduced, the suction unit will work for a very long time with little water so that the wall-climbing robot could carry its own water instead of being connected to a supply."
The paper has been published in the journal Physics of Fluids, and is available under open access terms.