Optimized Design of the Main Structure of a Wall-Climbing Robot for Bridge Detection Based on Negative Pressure Adsorption

To address the challenging task of inspecting hard-to-reach areas, such as high piers and the bottom of bridges, the paper developed a wall-climbing robot for bridge disease detection based on negative pressure adsorption. For the robot's own adsorption stability, this paper established and derived a formula for calculating the adsorption force index under conditions of anti-slip and anti-overturning, based on which the minimum adsorption force required by the robot to achieve stable wall adsorption at all angles was determined. The results show that to ensure the reliable operation of the robot, the adsorption module needs to provide 53.0 N adsorption force. The preliminary design of the centrifugal impeller was formulated based on empirical principles, followed by fluid mechanics simulation and response surface optimization of the impeller basin using Fluent. An evaluation function, comprising adsorption force and torque, was established to optimize the impeller design parameters to maximize the comprehensive evaluation function value of the adsorption module. Compared to the initial design scheme, the optimized design achieved a 3.4% increase in the evaluation function value while maintaining stability. Taking into consideration the aerodynamic performance of the chamber along with the topology optimization results, topology optimization of the negative pressure chamber was performed. The structure and arrangement of reinforcing ribs inside the chamber were obtained, with the reinforcing ribs connected to the wheel support arm designed in " 八"-shaped and linear hollow structures. This optimization reduced the maximum vertical displacement of the negative pressure chamber to 18.5% of the original model, with a minimal increase in mass of 16.9%. It shows that the precise layout effect of the strengthening rib is obvious, and the vertical deformation is successfully controlled within a reasonable range. Finally, a prototype was constructed using UTR6180 photosensitive resin and 3D printing technology, with approximate dimensions of 300 mm×280 mm×15 mm and a mass of approximately 1.15 kg. The performance test of the prototype was conducted under various working conditions, demonstrating that the wall-climbing robot can stably adsorb and move on various bridge walls without slipping or drifting.