Design of a heavy-duty tracked wall-climbing robot with liftable suction modules and static zero-radius steering

Purpose This paper addresses two key limitations of heavy-duty tracked wall-climbing robots using negative-pressure adhesion: suction-cup “lip curling,” which induces air leakage on contact, and the difficulty of steering in confined vertical spaces. Design/methodology/approach An integrated mechanical design is proposed, featuring a liftable suction module to prevent premature edge contact and a static lift-and-rotation mechanism for zero-radius steering. A static stability model is developed to derive the vacuum-pressure safety threshold (η = 3). A 50 kg full-scale prototype is built and tested on a vertical wooden panel, which provides a conservative baseline for anti-slip verification due to its lower friction coefficient than rough concrete. Findings The liftable mechanism suppresses suction-cup lip curling and maintains sealing integrity. A full-scale 50 kg prototype achieved stable vertical climbing at an average speed of approximately 20 mm/s and performed repeatable static on-the-spot steering with a mean rotation angle of about 11° per cycle under payloads up to 10 kg. During operation, the vacuum pressure generally remained at or below the theoretical safety threshold of −63.4 kPa (gauge); brief transients observed during steering-module handover did not cause slip or loss of adhesion. Originality/value The proposed liftable adhesion and static steering concept offers a practical structural solution for heavy-duty wall-climbing robots. The structure–model–experiment framework and prototype provide a useful reference for inspection and maintenance of large-scale infrastructure such as wind-turbine blades and cement facades.