Dynamic Modeling and Stability Analysis of a Leech-Inspired Wall-Climbing Robot

To meet the requirements for defect inspection in spent nuclear fuel (SNF) dry storage systems, this paper proposes a leech-inspired wall-climbing robot. The robot employs a parallel mechanism composed of two suction cups, three flexible screws (corrugated tubes), and two fixed plates, this configuration enables peristaltic locomotion and large-span transitions across intersecting wall surfaces. Based on the mechanical configuration and locomotion modes, a suction stability criterion is derived for different cases, and a dynamic model is further developed. Experiments are carried out in a simulated inspection environment to validate the proposed approach. The results show that the robot can move stably in confined spaces and can negotiate transitions between different wall surfaces with a large span.