Researchers Xin Li and Kaige Shai have created a suction unit that allows robots, and maybe one day humans, to walk on walls.
A wall-climbing robot uses the zero-pressure difference method to form suction. Source: Xin Li and Kaige Shi
To enable the robots to scale walls of various textures, the researchers created a zero-pressure difference (ZPD) method for the suction unit. Traditional vacuum suction methods cannot maintain suction on rough surfaces. When these units encounter rough surfaces, they experience vacuum leakage, which leads to suction failure.
The ZPD method overcomes this challenge by using a high-speed rotating water ring between the surface and the suction cup. This maintains the vacuum between the surface and the device. The centrifugal force of the rotating water eliminates the pressure difference at the boundary of the vacuum, maintaining high vacuum pressure inside the suction cup. The ZPD suction unit is lighter, smaller and more energy-efficient than traditional units.
The team tested the ZPD unit with three suction sizes and applications: on a robotic arm to grip and handle objects, on a hexapod wall-climbing robot and on a Spider-man-like climbing device.
The team said that their next step with the unit is to cut down on water consumption.
A paper on the new unit was published in Physics of Fluids.
