Abstract Gripping to smooth and wavy substrates, such as naturally occurring ice, presents a challenge for climbing robots in the field. Existing ice anchoring solutions require either substantial initial surface compression force (drilling; at least 50 Newtons) or require large energy expenditure (thermal picks; almost 1000 Joules). We present an anchoring mechanism capable of attaching to ice with lower initial surface compression force and lower energy consumption compared to drill-based or melt-based methods. The system leverages surface fracture caused by dynamic impacts with axes – inspired by mountaineers – to create indentations for grasping. A model describes the indentation depth, recoil energy, and surface compression force required for anchoring success, each as a function of impact energy. An integrated dual-ax gripper system successfully generates usable indents with as low as 8.3 Newtons of initial surface compression force and 8 Joules of combined mechanical potential energy on -14 ∘ C freshwater ice – a result consistent with first-principle model predictions. The gripper then successfully holds its own weight on steep glacier slopes in the field. These results indicate fracture-based grasping approaches are promising for climbing systems on ice. This concept can also apply to other surfaces such as wood, rock, and packed soil.
Galassi et al. (Fri,) studied this question.