A wall-climbing robot using gecko-inspired dry adhesives and underactuated modular connecting mechanism

This paper proposes the design, fabrication, and testing of a wall-climbing robot (WCR) using gecko-inspired dry adhesives. The robot consists of two tank-like modules, which utilize adhesive timing belts for locomotion and adhesion. A single module is firstly optimized in design to maximize the adhesive force. Then, an under-actuated compliant mechanism is designed to connect two modules. The robot mimics not only the gecko's multiscale adhesive structures but also its multiscale bio-adjustment mechanism. Inspired by the gecko's digital behavior, the robot can performs gripping-in and furling out motions to adjust preloading forces for each module on surfaces sloped from 0 to 180 degrees with respect to the level, via the under-actuated compliant mechanism. The robot's prototype is manufactured using 3Dprinting. Dry adhesives with pillar-patterned surface are fabricated. The adhesives then form a layer and cover the exterior surface of the flexible belts. Testing performances show that the robot can achieve stable scaling on the wall and ceiling with adjustable contact force, as well as the terrain-compatibility for surface transitioning.