Adhesion Characteristics of a Vortex-Generated Negative Pressure Suction Cup for Wall-Climbing Robots

This study investigates an air-based, vortex-driven, noncontact suction device for wall-climbing robots through theoretical analysis, computational fluid dynamics (CFD) simulations, and experiments. An engineering model is derived to describe the mean pressure distribution in the suction gap and to separate the totally normal force into a pressure-differential component and an impeller-induced thrust component. CFD simulations using the shear stress transport k-omega turbulence model quantify the effects of rotational speed, diameter of the negative pressure chamber, height of the negative pressure chamber, and suction gap. The suction force increases nonlinearly with rotational speed and diameter of the negative pressure chamber, while it exhibits a clear optimum with respect to height of the negative pressure chamber and suction gap. Experimental measurements validate the numerical trends and support the proposed mechanism, with a maximum relative deviation within 15%. The results provide design-oriented guidance for parameter selection and performance optimization.