Enhanced Acoustic Adhesion Enabling Agile and Small Wall-Climbing Robot Design With Anisotropic Origami Structure.

Small inspection robots are highly desirable for detecting damage within confined spaces. By vibrating a disk on a surface, a thin air layer with negative pressure-known as acoustic adhesion-is generated, which offers a strategy for creating compact yet strongly climbing robots. However, it is highly sensitive to disturbances. Any transmitted vibrations or improper torque can compromise the robot's airtightness, causing it to fall. This fatal flaw has hindered the development of reliable acoustic climbing robots. Here, we present a 28 g, 50 mm inspection robot capable of navigating vertical walls (8 cm/s) and ceilings (20 cm/s) while carrying a 100 g payload. We decouple vibration and load effects using a ring connection, approximately doubling the adhesion. Moreover, an anisotropic origami spring is designed to maintain close contact between the disk and the substrate, ensuring durable, robust adhesion. By combining acoustic adhesion with optimized structural designs, we overcome two major challenges: failure from vibration coupling and demanding assembly. Our robot thereby achieves high mobility and a large payload capacity. We demonstrate the robot's agility and intelligence through maze navigation and inspection of real blades, in which it autonomously adjusts its path. This work offers a potential solution for in-situ damage detection.