A Multimodal Dual-Segment Soft Robot With Ground-to-Ceiling Transition

Although various soft robots with remarkable mobility have been developed, enabling a single robot to achieve multi-terrain locomotion with transitions across ground, vertical walls, and ceilings remains a formidable challenge. This paper presents a multimodal dual-segment soft robot capable of omnidirectional terrestrial locomotion, vertical climbing and ceiling crawling, and smooth inter-surface transitioning. The robot's wall and ceiling locomotion ability is realized through improved segment design featuring lightweight construction, enhanced deformability and load capacity, whereas its transitional capability is facilitated by coordinated dual-segmental gaits and compensation of gravity-induced deformation. Through cross-sectional improvement, the redesigned segment demonstrates enhanced bending capability with a maximum bending angle exceeding 180<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>, achieving a 105% workspace expansion compared to the baseline design. Experimental characterization reveals performance metrics of the robot: a maximum terrestrial velocity of 33.2 mm/s, angular turning rate of 30<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>/s, and transition capability while carrying 50 g payload. Furthermore, we demonstrate the robot's practical utility by integrating an onboard camera to successfully execute multi-surface inspection tasks in confined space and aircraft wing cavity, validating its potential for deployment in real-world unstructured environments.