Designing passive stability in mountain goat-inspired robotic feet through situated heuristics

Abstract This paper explores the mechanical intelligence of a mountain goat-type hoof designed for passive dynamic slip resistance on inclined natural surfaces. We hypothesised that specific hoof features can be tuned to leverage sloped terrain characteristics to reduce slip. We took a situated heuristics-based approach to iteratively design the hoof, conducting multiple experiments in an Alpine-type environment. Results show that combining surface geometry, material, and direction-dependent compliance in various degrees of freedom is key to reducing slip. Indoor tests across slope angles and loads show that stick-slip events correlate with reduced slip distance following a forced slip from rest. Additionally, tests on different slope surfaces showed that the passive slip dynamics also depend on the mechanical properties of the slope itself. Overall, these results affirm that a situated heuristics-based design approach effectively builds mechanical intelligence in a robot, enabling it to optimise interactions with its environment for improved slip resistance.