Research on the Design of Variable Stiffness Adhesive Feet and Cooperative Crawling Mechanism for Soft Bionic Gecko-Inspired Wall-Climbing Robots

Abstract

Gecko-inspired soft robots offer unique advantages for confined-space operations. Here, we introduce a soft climbing robot designed for tasks such as spacecraft inspection and disaster response. Unlike conventional attachment mechanisms relying on claws, suction-based adhesion, or electromagnetic components, the proposed system integrates polyurethane-based dry adhesive footpads, which passively adapt to a wide range of surfaces and require no external power. A key innovation of this work is the incorporation of variable stiffness footpads capable of actively tuning their mechanical properties in response to surface interaction demands, thereby optimizing both attachment stability and detachment efficiency during locomotion. Experimental characterization indicates that these footpads achieve an adhesion-to-detachment force ratio of 11:77, demonstrating a favorable balance between strong attachment and reliable release. Furthermore, the robot integrates a bioinspired crawling mechanism that synchronizes limb actuation with the deformation of a flexible spine structure, effectively enhancing propulsion and maneuverability across irregular terrain. Validation experiments conducted on diverse surface types confirm the robot’s environmental adaptability and highlight its potential for deployment in constrained, unstructured, and dynamically changing operational contexts.