Experimental investigation on climbing robot using rotation-flow adsorption unit

Traditional climbing robots that use vacuum suckers have some technical problems, e.g., inability to climb coarse walls, frictional resistance and abrasion of suckers, and poor obstacle-surmounting ability. In this study, a new negative pressure adsorption mechanism is applied to the design of a climbing robot. This mechanism generates and maintains negative pressure and adsorption force by using the air's rotational inertia effect; therefore, the structure incorporating this mechanism is called the rotational-flow adsorption unit. The most important characteristic of the adsorption unit is that it can function without being in contact with the wall, which fundamentally solves these technical problems associated with traditional climbing robots. In this study, we designed a square-shaped rotational-flow adsorption unit to improve the robot's load ability (18% increase in the adsorption force) and designed a soft skirt structure to improve the robot's obstacle-surmounting ability (e.g., passing through 15-mm-high bulges). Finally, we fabricated a prototype of the climbing robot and tested it on several actual walls (extremely coarse wall, wall containing deep groove, and wall containing large bulges). The test results show that our prototype robot can move stably on coarse walls and can pass over large grooves and bulges easily.