Design and analysis of 4SRRR legged wall-climbing robot

Currently, manual detection of wall welds and surface microcracks on ships and oil tanks is not only inefficient but also potentially hazardous. This study proposes a 4SRRR legged wall-climbing robot with redundant actuation, designed to accommodate the characteristics of permeable materials, to address this issue. First, the robot's gait is examined, followed by a thorough examination of its stability on both vertical and horizontal surfaces. For vertical surfaces, a statics analysis is conducted to prevent the risk of falling, whereas, for horizontal surfaces, the margin of stability is evaluated. To determine the required degrees of freedom for the robot to complete its assigned tasks, the screw theory is applied. The De-navit-Hartenberg (D-H) method is then used to analyze the forward and inverse kinematics of the robot. In addition, the La-grange balance method is used to analyze the swing leg's dynamics. A control algorithm for impedance is developed for situations in which the swinging leg collides with the ground. A prototype is then designed and tested to assess the wall-climbing performance and the efficacy of the impedance control strategy when the swinging leg experiences an impact. This research seeks to provide a solid theoretical foundation and technical support for the engineering application of wall-climbing robots, thereby enhancing the efficiency and safety of wall weld and surface microcrack detection processes in ships and oil tanks.