Theoretical and Experimental Study and Design Method of Blade Height of a Rotational-Flow Suction Unit in a Wall-Climbing Robot

Abstract

A wall-climbing robot that uses a rotational-flow suction unit to be non-contact-absorbed onto walls can climb rough walls and overstep obstacles. In the rotational-flow suction unit, the air driven by the blades rotates at a high speed within a chamber, thereby creating and maintaining a negative pressure distribution. This study is focused on the modeling and design of the blade height. First, a theoretical model of the rotation flow, containing two important parameters (i.e., blade height Hb and clearance h), was established and verified experimentally. Furthermore, the computational fluid dynamics (CFD) method was applied to illustrate the secondary flow relative to the blades, revealing that it gives rise to a nonlinear velocity distribution. It was found that an increase in the blade height greatly improves the F–h characteristics; in addition, the relationship between the power consumption and suction force (E˙−F curve) is mainly determined by the clearance h instead of the blade height Hb. Based on these findings, we propose a design method for determining the suitable blade height. According to the characteristic load curves of the suction units (i.e., the T–ω curves) and the motor characteristics, suitable blades can be selected to match the motor operation (i.e., nominal operating state).

CREST: A low energy consumption wall climbing robot with passive impactive negative pressure adhesion

“…Commonly used adhesion methods in WCR including magnetic [10][11][12], electrostatic [13,14], grippers [15,16], bio-inspired [17][18][19][20][21][22][23][24][25], as well as negative pressure [9,[26][27][28][29][30][31][32][33][34][35][36][37][38][39]. One commonly used method is magnetic adhesion, employing permanent magnets [10], electromagnets [11], or a hybrid adhesion with permanent and electromagnets [12] to adhere to metallic surfaces.…”

A heavy-load wall-climbing robot for bridge concrete structures inspection

“…The bionic adhesion inspired by animals such as geckos requires the adhered surface to have a high degree of cleanliness. Electrostatic adhesion technology currently struggles to provide sufficient adhesion force to support the weight of inspection device (Fang et al, 2022). There are no published literatures on the application of robots using related adhesion technologies in bridge inspection.…”

Design and optimization of wall-climbing robot impeller by genetic algorithm based on computational fluid dynamics and kriging model

“…Computational fluid dynamics simulation (CFD) and other methods can be used to analyze, improve and optimize the adsorption device more conveniently 26 . Chen studied the blade vortex's theoretical model, modeled the rotating blade's height, analyzed the secondary flow of the blade by the CFD method, and proposed a blade design method based on the characteristics of the motor 27 . Fallah performed numerical calculations and CFD analysis on the wall-climbing robot designed by his vortex current adsorption to obtain the optimal data and designed a new negative pressure cavity structure 28 .…”