According tomedia New Atlas, although there are already power suckers that allow people or robots to climb walls, they can only work on smooth surfaces. However, chinese scientists have now developed a system that adheres to rough surfaces by rotating water. The technique, known as “zero pressure differential” (ZPD), was developed by a Zhejiang University research team led by Li Wei and Shi Kaige.
It still contains a soft rubber cup, but each cup contains a circle of water that rotates at high speed along the outer edge of the cup and is located at the boundary between the cup and the rough surface applied. The resulting inertial force creates a pressure gradient that allows a high vacuum to be maintained in the center of the vacuum area of the cup, while maintaining the pressure at the boundary equal to atmospheric pressure.
In a conventional power suction, because of the large pressure difference at the boundary, the vacuum will easily leak and fall when placed on a surface that is not completely smooth. However, because this difference is eliminated in the new system, no such leak occurs regardless of how textured the surface is. Moreover, the additional function required for ZPD is that much less power is required to maintain a given suction force than conventional systems. The entire unit is also smaller and lighter than the traditional model.
So far, three sizes of ZPD cups have been successfully tested on robotic arms that can grip objects, “Spider-Man” devices that allow people to climb walls, and six-foot climbing robots. The latter aroused people’s interest.
“Compared to other climbing robots, robots with our ZPD-based suction cup units have achieved a surprising improvement in performance, ” Li said. “The next step in this study is to reduce water consumption. If water consumption can be reduced, the suction cup unit will work for a long time with a small amount of water so that the rock-climbing robot can carry water on its own instead of connecting to the power supply. “
A paper on the study was recently published in the journal Physics of Fluids.